Java/Development Class/Hash Code
Содержание
- 1 A hash-code generator and a collection of static hash-code generation methods.
- 2 An implementation of the HMACT64 keyed hashing algorithm
- 3 A very efficient java hash algorithm, based on the BuzHash algoritm
- 4 Computing hash codes
- 5 Easy implementation of hashCode
- 6 Get hash code for primitive data types
- 7 Gets the hash code of an object returning zero when the object is null
- 8 Hash 32 String
- 9 Hash 64 String
- 10 Hash Code Builder
- 11 HashCode generation
- 12 MD5 hash generator
- 13 MD5 hashing: Encodes a string
- 14 MD5 String
- 15 Null Safe Hash Code
- 16 Return as hash code for the given object
- 17 Secure Hash
- 18 Unify Hash
A hash-code generator and a collection of static hash-code generation methods.
<source lang="java">
/*
* JBoss, Home of Professional Open Source * Copyright 2005, JBoss Inc., and individual contributors as indicated * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */
import java.io.Serializable; /**
* A hash-code generator and a collection of static hash-code generation * methods. * * @version $Revision: 2800 $ * @author */
@SuppressWarnings("unchecked") public final class HashCode implements Serializable, Cloneable, Comparable {
/** The serialVersionUID */
private static final long serialVersionUID = 2391396931740264021L;
/** Hashcode for a "null" value. */
private static final int NULL_HASHCODE = 0;
/** Hashcode for a "true" boolean */
private static final int TRUE_HASHCODE = 1231; // completely arbitrary
/** Hashcode for a "false" boolean */
private static final int FALSE_HASHCODE = 1237; // completely arbitrary
/** The hash-code value. */
private int value;
/**
* Construct a new HashCode using the given int as the
* base value.
*
* @param value
* int to use as the base value.
*/
public HashCode(final int value) {
this.value = value;
}
/**
* Construct a new HashCode.
*/
public HashCode() {
this(0);
}
/**
* Add the hash-code of the given value.
*
* @param b
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final boolean b) {
value ^= generate(b);
return this;
}
/**
* Add the hash-code of the given value.
*
* @param n
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final byte n) {
value ^= n;
return this;
}
/**
* Add the hash-code of the given value.
*
* @param n
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final char n) {
value ^= n;
return this;
}
/**
* Add the hash-code of the given value.
*
* @param n
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final short n) {
value ^= n;
return this;
}
/**
* Add the hash-code of the given value.
*
* @param n
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final int n) {
value ^= n;
return this;
}
/**
* Add the hash-code of the given value.
*
* @param n
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final long n) {
value ^= generate(n);
return this;
}
/**
* Add the hash-code of the given value.
*
* @param f
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final float f) {
value ^= generate(f);
return this;
}
/**
* Add the hash-code of the given value.
*
* @param f
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final double f) {
value ^= generate(f);
return this;
}
/**
* Add the hash-code of the given object.
*
* @param obj
* Value to get hash-code from.
* @return This HashCode.
*/
public HashCode add(final Object obj) {
value ^= generate(obj);
return this;
}
/**
* Get the hash-code.
*
* @return Hash-code.
*/
public int hashCode() {
return value;
}
/**
* Compares this object with the specified int for order.
*
* @param other
* Value to compare with.
* @return A negative integer, zero, or a positive integer as this object is
* less than, equal to, or greater than the specified object.
*/
public int compareTo(final int other) {
return (value < other) ? -1 : (value == other) ? 0 : 1;
}
/**
* Compares this object with the specified object for order.
*
* @param obj
* Value to compare with.
* @return A negative integer, zero, or a positive integer as this object is
* less than, equal to, or greater than the specified object.
*
* @throws ClassCastException
* Object is not a HashCode.
*/
public int compareTo(final Object obj) throws ClassCastException {
HashCode hashCode = (HashCode) obj;
return compareTo(hashCode.value);
}
/**
* Test the equality of this HashCode and another object.
*
* @param obj
* Object to test equality with.
* @return True if object is equal.
*/
public boolean equals(final Object obj) {
if (obj == this)
return true;
if (obj != null && obj.getClass() == getClass()) {
return value == ((HashCode) obj).value;
}
return false;
}
/**
* Return a string representation of this HashCode.
*
* @return A string representation of this HashCode.
*/
public String toString() {
return String.valueOf(value);
}
/**
* Return a cloned copy of this HashCode.
*
* @return Cloned HashCode.
*/
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new InternalError();
}
}
// ///////////////////////////////////////////////////////////////////////
// Generation Methods //
// ///////////////////////////////////////////////////////////////////////
/**
* Generate a hash code for a boolean value.
*
* @param value
* Boolean value to generate hash code from.
* @return Hash code.
*/
public static int generate(final boolean value) {
return value ? TRUE_HASHCODE : FALSE_HASHCODE;
}
/**
* Generate a hash code for a long value.
*
* @param value
* Long value to generate hash code from.
* @return Hash code.
*/
public static int generate(final long value) {
return (int) (value ^ (value >> 32));
}
/**
* Generate a hash code for a double value.
*
* @param value
* Double value to generate hash code from.
* @return Hash code.
*/
public static int generate(final double value) {
return generate(Double.doubleToLongBits(value));
}
/**
* Generate a hash code for a float value.
*
* @param value
* Float value to generate hash code from.
* @return Hash code.
*/
public static int generate(final float value) {
return Float.floatToIntBits(value);
}
/**
* Generate a hash code for a byte array.
*
* @param bytes
* An array of bytes to generate a hash code from.
* @return Hash code.
*/
public static int generate(final byte[] bytes) {
int hashcode = 0;
for (int i = 0; i < bytes.length; i++) {
hashcode <<= 1;
hashcode ^= bytes[i];
}
return hashcode;
}
/**
* Generate a hash code for an object array.
*
* * Does not handle nested primitive array elements. * * @param array * Array to generate hashcode for. * @param deep * True to traverse elements which are arrays to determine the * elements hash code. * @return Hash code. */ public static int generate(final Object array[], final boolean deep) { int hashcode = 0; for (int i = 0; i < array.length; i++) { if (deep && (array[i] instanceof Object[])) { hashcode ^= generate((Object[]) array[i], true); } else { hashcode ^= array[i].hashCode(); } } return hashcode; } /** * Generate a shallow hash code for an object array. * * @param array * Array to generate hashcode for. * @return Hash code. */ public static int generate(final Object array[]) { return generate(array, false); } /** * Generate a hash code for an object. * * @param obj * Object to generate hashcode for. * @return Hash code. */ public static int generate(final Object obj) { if (obj != null) { return obj.hashCode(); } return NULL_HASHCODE; } } </source>
An implementation of the HMACT64 keyed hashing algorithm
<source lang="java">
/* HMACT64 keyed hashing algorithm
* Copyright (C) 2003 "Eric Glass" <jcifs at samba dot org> * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
import java.security.MessageDigest; /**
* This is an implementation of the HMACT64 keyed hashing algorithm. * HMACT64 is defined by Luke Leighton as a modified HMAC-MD5 (RFC 2104) * in which the key is truncated at 64 bytes (rather than being hashed * via MD5). */
public class HMACT64 extends MessageDigest implements Cloneable {
private static final int BLOCK_LENGTH = 64;
private static final byte IPAD = (byte) 0x36;
private static final byte OPAD = (byte) 0x5c;
private MessageDigest md5;
private byte[] ipad = new byte[BLOCK_LENGTH];
private byte[] opad = new byte[BLOCK_LENGTH];
/**
* Creates an HMACT64 instance which uses the given secret key material.
*
* @param key The key material to use in hashing.
*/
public HMACT64(byte[] key) {
super("HMACT64");
int length = Math.min(key.length, BLOCK_LENGTH);
for (int i = 0; i < length; i++) {
ipad[i] = (byte) (key[i] ^ IPAD);
opad[i] = (byte) (key[i] ^ OPAD);
}
for (int i = length; i < BLOCK_LENGTH; i++) {
ipad[i] = IPAD;
opad[i] = OPAD;
}
try {
md5 = MessageDigest.getInstance("MD5");
} catch (Exception ex) {
throw new IllegalStateException(ex.getMessage());
}
engineReset();
}
private HMACT64(HMACT64 hmac) throws CloneNotSupportedException {
super("HMACT64");
this.ipad = hmac.ipad;
this.opad = hmac.opad;
this.md5 = (MessageDigest) hmac.md5.clone();
}
public Object clone() {
try {
return new HMACT64(this);
} catch (CloneNotSupportedException ex) {
throw new IllegalStateException(ex.getMessage());
}
}
protected byte[] engineDigest() {
byte[] digest = md5.digest();
md5.update(opad);
return md5.digest(digest);
}
protected int engineDigest(byte[] buf, int offset, int len) {
byte[] digest = md5.digest();
md5.update(opad);
md5.update(digest);
try {
return md5.digest(buf, offset, len);
} catch (Exception ex) {
throw new IllegalStateException();
}
}
protected int engineGetDigestLength() {
return md5.getDigestLength();
}
protected void engineReset() {
md5.reset();
md5.update(ipad);
}
protected void engineUpdate(byte b) {
md5.update(b);
}
protected void engineUpdate(byte[] input, int offset, int len) {
md5.update(input, offset, len);
}
}
</source>
A very efficient java hash algorithm, based on the BuzHash algoritm
<source lang="java">
/*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
/**
* A very efficient java hash algorithm, based on the BuzHash algoritm by Robert * Uzgalis (see http://www.serve.net/buz/hash.adt/java.000.html for more * information). BuzHash is Copyright (c)1996 Robert Uzgalis, All Rights * Reserved. Used with kind permission of the author * * @version $Id: HashUtil.java 587751 2007-10-24 02:41:36Z vgritsenko $ */
public final class HashUtil {
private static long initial_hash = 0xe12398c6d9ae3b8aL; // initial values
private static long mix_master[/* 0:255 */] = {
/* 000 */0x4476081a7043a46fL, 0x45768b8a6e7eac19L, 0xebd556c1cf055952L,
/* */0x72ed2da1bf010101L, 0x3ff2030b128e8a64L,
/* 005 */0xcbc330238adcfef2L, 0x737807fe42e20c6cL, 0x74dabaedb1095c58L,
/* */0x968f065c65361d67L, 0xd3f4018ac7a4b199L,
/* 010 */0x954b389b52f24df2L, 0x2f97a9d8d0549327L, 0xb9bea2b49a3b180fL,
/* */0xaf2f42536b21f2ebL, 0x85d991663cff1325L,
/* 015 */0xb9e1260207b575b9L, 0xf3ea88398a23b7e2L, 0xfaf8c83ffbd9091dL,
/* */0x4274fe90834dbdf9L, 0x3f20b157b68d6313L,
/* 020 */0x68b48972b6d06b93L, 0x694837b6eba548afL, 0xeecb51d1acc917c9L,
/* */0xf1c633f02dffbcfaL, 0xa6549ec9d301f3b5L,
/* 025 */0x451dc944f1663592L, 0x446d6acef6ce9e4fL, 0x1c8a5b3013206f02L,
/* */0x5908ca36f2dc50f7L, 0x4fd55d3f3e880a87L,
/* 030 */0xa03a8dbeabbf065dL, 0x3ccbbe078fabcb6dL, 0x1da53a259116f2d0L,
/* */0xfb27a96fcb9af152L, 0x50aba242e85aec09L,
/* 035 */0x24d4e414fc4fc987L, 0x83971844a9ce535eL, 0xc26a3fdeb849398eL,
/* */0xc2380d044d2e70d8L, 0xab418aa8ae19b18fL,
/* 040 */0xd95b6b9247d5ebeaL, 0x8b3b2171fdc60511L, 0xe15cd0ae3fcc44afL,
/* */0x5a4e27f914a68f17L, 0x377bd28ca09aafdcL,
/* 045 */0xbbeb9828594a3294L, 0x7c8df263ae1de1b9L, 0xba0a48a5fd1c1dd0L,
/* */0x57cc1b8818b98ee6L, 0x8c570975d357dabcL,
/* 050 */0x76bdcd6f2e8826aaL, 0x529b15b6ec4055f1L, 0x9147c7a54c34f8a9L,
/* */0x2f96a7728170e402L, 0xe46602f455eca72eL,
/* 055 */0x22834c4dd1bde03fL, 0x2644cf5a25e368ffL, 0x907c6de90b120f4aL,
/* */0xadfe8ba99028f728L, 0xa85199ae14df0433L,
/* 060 */0x2d749b946dd3601eL, 0x76e35457aa052772L, 0x90410bf6e427f736L,
/* */0x536ad04d13e35041L, 0x8cc0d76769b76914L,
/* 065 */0xae0249f6e3b3c01cL, 0x1bdfd075307d6fafL, 0xd8e04f70c221deccL,
/* */0x4ab23622a4281a5dL, 0x37a5613da2fcaba7L,
/* 070 */0x19a56203666d4a9fL, 0x158ffab502c4be93L, 0x0bee714e332ecb2fL,
/* */0x69b71a59f6f74ab0L, 0x0fc7fc622f1dfe8fL,
/* 075 */0x513966de7152a6f9L, 0xc16fae9cc2ea9be7L, 0xb66f0ac586c1899eL,
/* */0x11e124aee3bdefd7L, 0x86cf5a577512901bL,
/* 080 */0x33f33ba6994a1fbdL, 0xde6c4d1d3d47ff0dL, 0x6a99220dc6f78e66L,
/* */0x2dc06ca93e2d25d2L, 0x96413b520134d573L,
/* 085 */0xb4715ce8e1023afaL, 0xe6a75900c8c66c0aL, 0x6448f13ad54c12edL,
/* */0xb9057c28cf6689f0L, 0xf4023daf67f7677aL,
/* 090 */0x877c2650767b9867L, 0xb7ea587dcd5b2341L, 0xc048cf111733f9bcL,
/* */0x112012c15bc867bfL, 0xc95f52b1d9418811L,
/* 095 */0xa47e624ee7499083L, 0x26928606df9b12e8L, 0x5d020462ec3e0928L,
/* */0x8bbde651f6d08914L, 0xd5db83db758e524aL,
/* 100 */0x3105e355c000f455L, 0xdd7fe1b81a786c79L, 0x1f3a818c8e012db1L,
/* */0xd902de819d7b42faL, 0x4200e63325cda5f0L,
/* 105 */0x0e919cdc5fba9220L, 0x5360dd54605a11e1L, 0xa3182d0e6cb23e6cL,
/* */0x13ee462c1b483b87L, 0x1b1b6087b997ee22L,
/* 110 */0x81c36d0b877f7362L, 0xc24879932c1768d4L, 0x1faa756e1673f9adL,
/* */0x61651b24d11fe93dL, 0x30fe3d9304e1cde4L,
/* 115 */0x7be867c750747250L, 0x973e52c7005b5db6L, 0x75d6b699bbaf4817L,
/* */0x25d2a9e97379e196L, 0xe65fb599aca98701L,
/* 120 */0x6ac27960d24bde84L, 0xdfacc04c9fabbcb6L, 0xa46cd07f4a97882bL,
/* */0x652031d8e59a1fd8L, 0x1185bd967ec7ce10L,
/* 125 */0xfc9bd84c6780f244L, 0x0a0c59872f61b3ffL, 0x63885727a1c71c95L,
/* */0x5e88b4390b2d765cL, 0xf0005ccaf988514dL,
/* 130 */0x474e44280a98e840L, 0x32de151c1411bc42L, 0x2c4b86d5aa4482c2L,
/* */0xccd93deb2d9d47daL, 0x3743236ff128a622L,
/* 135 */0x42ed2f2635ba5647L, 0x99c74afd18962dbdL, 0x2d663bb870f6d242L,
/* */0x7912033bc7635d81L, 0xb442862f43753680L,
/* 140 */0x94b1a5400aeaab4cL, 0x5ce285fe810f2220L, 0xe8a7dbe565d9c0b1L,
/* */0x219131af78356c94L, 0x7b3a80d130f27e2fL,
/* 145 */0xbaa5d2859d16b440L, 0x821cfb6935771070L, 0xf68cfb6ee9bc2336L,
/* */0x18244132e935d2fdL, 0x2ed0bda1f4720cffL,
/* 150 */0x4ed48cdf6975173cL, 0xfd37a7a2520e2405L, 0x82c102b2a9e73ce2L,
/* */0xadac6517062623a7L, 0x5a1294d318e26104L,
/* 155 */0xea84fe65c0e4f061L, 0x4f96f8a9464cfee9L, 0x9831dff8ccdc534aL,
/* */0x4ca927cd0f192a14L, 0x030900b294b71649L,
/* 160 */0x644b263b9aeb0675L, 0xa601d4e34647e040L, 0x34d897eb397f1004L,
/* */0xa6101c37f4ec8dfcL, 0xc29d2a8bbfd0006bL,
/* 165 */0xc6b07df8c5b4ed0fL, 0xce1b7d92ba6bccbeL, 0xfa2f99442e03fe1bL,
/* */0xd8863e4c16f0b363L, 0x033b2cccc3392942L,
/* 170 */0x757dc33522d6cf9cL, 0xf07b1ff6ce55fec5L, 0x1569e75f09b40463L,
/* */0xfa33fa08f14a310bL, 0x6eb79aa27bbcf76bL,
/* 175 */0x157061207c249602L, 0x25e5a71fc4e99555L, 0x5df1fe93de625355L,
/* */0x235b56090c1aa55dL, 0xe51068613eaced91L,
/* 180 */0x45bd47b893b9ff1eL, 0x6595e1798d381f2dL, 0xc9b5848cbcdb5ba8L,
/* */0x65985146ff7792bcL, 0x4ab4a17bf05a19a0L,
/* 185 */0xfd94f4ca560ffb0cL, 0xcf9bad581a68fa68L, 0x92b4f0b502b1ce1aL,
/* */0xbcbec0769a610474L, 0x8dbd31ded1a0fecbL,
/* 190 */0xdd1f5ed9f90e8533L, 0x61c1e6a523f84d95L, 0xf24475f383c110c4L,
/* */0xdb2dffa66f90588dL, 0xac06d88e9ee04455L,
/* 195 */0xa215fc47c40504baL, 0x86d7caebfee93369L, 0x9eaec31985804099L,
/* */0x0fba2214abe5d01bL, 0x5a32975a4b3865d6L,
/* 200 */0x8cceebc98a5c108fL, 0x7e12c4589654f2dcL, 0xa49ad49fb0d19772L,
/* */0x3d142dd9c406152bL, 0x9f13589e7be2b8a5L,
/* 205 */0x5e8dbac1892967adL, 0xcc23b93a6308e597L, 0x1ef35f5fe874e16aL,
/* */0x63ae9cc08d2e274fL, 0x5bbabee56007fc05L,
/* 210 */0xabfd72994230fc39L, 0x9d71a13a99144de1L, 0xd9daf5aa8dcc89b3L,
/* */0xe145ec0514161bfdL, 0x143befc2498cd270L,
/* 215 */0xa8e192557dbbd9f8L, 0xcbeda2445628d7d0L, 0x997f0a93205d9ea4L,
/* */0x01014a97f214ebfaL, 0x70c026ffd1ebedafL,
/* 220 */0xf8737b1b3237002fL, 0x8afcbef3147e6e5eL, 0x0e1bb0684483ebd3L,
/* */0x4cbad70ae9b05aa6L, 0xd4a31f523517c363L,
/* 225 */0xdb0f057ae8e9e8a2L, 0x400894a919d89df6L, 0x6a626a9b62defab3L,
/* */0xf907fd7e14f4e201L, 0xe10e4a5657c48f3fL,
/* 230 */0xb17f9f54b8e6e5dcL, 0x6b9e69045fa6d27aL, 0x8b74b6a41dc3078eL,
/* */0x027954d45ca367f9L, 0xd07207b8fdcbb7ccL,
/* 235 */0xf397c47d2f36414bL, 0x05e4e8b11d3a034fL, 0x36adb3f7122d654fL,
/* */0x607d9540eb336078L, 0xb639118e3a8b9600L,
/* 240 */0xd0a406770b5f1484L, 0x3cbee8213ccfb7c6L, 0x467967bb2ff89cf1L,
/* */0xb115fe29609919a6L, 0xba740e6ffa83287eL,
/* 245 */0xb4e51be9b694b7cdL, 0xc9a081c677df5aeaL, 0x2e1fbcd8944508ccL,
/* */0xf626e7895581fbb8L, 0x3ce6e9b5728a05cbL,
/* 250 */0x46e87f2664a31712L, 0x8c1dc526c2f6acfaL, 0x7b4826726e560b10L,
/* */0x2966e0099d8d7ce1L, 0xbb0dd5240d2b2adeL, 0x0d527cc60bbaa936L };
/**
* This is buzhash the hash function on which most other Hash methods are
* built.
*/
private static long buzhash(StringBuffer arg) {
/* Hash StringBuffer */
long h = initial_hash;
for (int i = 0; i < arg.length(); ++i)
h = (h << 1) ^ (h >>> 63) ^ mix_master[(arg.charAt(i) ^ (arg.charAt(i) >>> 8)) & 0xff];
return h;
}
/**
* This is buzhash the hash function on which most other Hash methods are
* built.
*/
private static long buzhash(String arg) {
/* Hash StringBuffer */
long h = initial_hash;
for (int i = 0; i < arg.length(); ++i)
h = (h << 1) ^ (h >>> 63) ^ mix_master[(arg.charAt(i) ^ (arg.charAt(i) >>> 8)) & 0xff];
return h;
}
/**
* Hash a String.
*
* @param arg
* The String to be hashed
* @return The hash for the input.
*/
public static long hash(String arg) {
// Make Hash from String
return buzhash(arg);
}
/**
* Hash a String.
*
* @param arg
* The String represented by the StringBuffer to be hashed
* @return The hash for the input.
*/
public static long hash(StringBuffer arg) {
// Make Hash from StringBuffer
return buzhash(arg);
}
}
</source>
Computing hash codes
<source lang="java">
/*
* JBoss DNA (http://www.jboss.org/dna) * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. Some portions may be licensed * to Red Hat, Inc. under one or more contributor license agreements. * See the AUTHORS.txt file in the distribution for a full listing of * individual contributors. * * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA * is licensed to you under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * JBoss DNA is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */
import java.util.Arrays; /**
* Utilities for easily computing hash codes. The algorithm should generally produce good distributions for use in hash-based * containers or collections, but as expected does always result in repeatable hash codes given the inputs. * @author Randall Hauch */
public class HashCode {
// Prime number used in improving distribution: 1,000,003
private static final int PRIME = 103;
/**
* Compute a combined hash code from the supplied objects. This method always returns 0 if no objects are supplied.
* @param objects the objects that should be used to compute the hash code
* @return the hash code
*/
public static int compute( Object... objects ) {
return compute(0, objects);
}
/**
* Compute a combined hash code from the supplied objects using the supplied seed.
* @param seed a value upon which the hash code will be based; may be 0
* @param objects the objects that should be used to compute the hash code
* @return the hash code
*/
protected static int compute( int seed, Object... objects ) {
if (objects == null || objects.length == 0) {
return seed * HashCode.PRIME;
}
// Compute the hash code for all of the objects ...
int hc = seed;
for (Object object : objects) {
hc = HashCode.PRIME * hc;
if (object instanceof byte[]) {
hc += Arrays.hashCode((byte[])object);
} else if (object instanceof boolean[]) {
hc += Arrays.hashCode((boolean[])object);
} else if (object instanceof short[]) {
hc += Arrays.hashCode((short[])object);
} else if (object instanceof int[]) {
hc += Arrays.hashCode((int[])object);
} else if (object instanceof long[]) {
hc += Arrays.hashCode((long[])object);
} else if (object instanceof float[]) {
hc += Arrays.hashCode((float[])object);
} else if (object instanceof double[]) {
hc += Arrays.hashCode((double[])object);
} else if (object instanceof char[]) {
hc += Arrays.hashCode((char[])object);
} else if (object instanceof Object[]) {
hc += Arrays.hashCode((Object[])object);
} else if (object != null) {
hc += object.hashCode();
}
}
return hc;
}
}
</source>
Easy implementation of hashCode
<source lang="java">
// Copyright (c) 2003-2009, Jodd Team (jodd.org). All Rights Reserved.
/**
* Collected methods which allow easy implementation of*hashCode(). * Based on items #7 and #8 from "Effective Java" book. * <p> * Usage scenario:
* int result = HashCodeUtil.SEED; * result = HashCodeUtil.hash(result, fIsDecrepit); * ... * return result; *
*/
public class HashCode {
/**
* An initial hash code value to which is added contributions from fields.
* Using a non-zero value decreases collisions of hash code values.
*/
public static final int SEED = 173;
public static final int PRIME = 37;
// ---------------------------------------------------------------- boolean
/**
* Calculates hash code for booleans.
*/
public static int hash(int seed, boolean aBoolean) {
return (PRIME * seed) + (aBoolean ? 1231 : 1237);
}
/**
* Calculates hash code for boolean array.
*/
public static int hash(int seed, boolean[] booleanArray) {
if (booleanArray == null) {
return 0;
}
for (boolean aBoolean : booleanArray) {
seed = hash(seed, aBoolean);
}
return seed;
}
/**
* Calculates hash code for boolean array.
*/
public static int hashBooleanArray(int seed, boolean... booleanArray) {
return hash(seed, booleanArray);
}
// ---------------------------------------------------------------- char
/**
* Calculates hash code for chars.
*/
public static int hash(int seed, char aChar) {
return (PRIME * seed) + (int) aChar;
}
/**
* Calculates hash code for char array.
*/
public static int hash(int seed, char[] charArray) {
if (charArray == null) {
return 0;
}
for (char aChar : charArray) {
seed = hash(seed, aChar);
}
return seed;
}
/**
* Calculates hash code for char array.
*/
public static int hashCharArray(int seed, char... charArray) {
return hash(seed, charArray);
}
// ---------------------------------------------------------------- ints
/**
* Calculates hash code for ints.
*/
public static int hash(int seed, int anInt) {
return (PRIME * seed) + anInt;
}
/**
* Calculates hash code for int array.
*/
public static int hash(int seed, int[] intArray) {
if (intArray == null) {
return 0;
}
for (int anInt : intArray) {
seed = hash(seed, anInt);
}
return seed;
}
/**
* Calculates hash code for int array.
*/
public static int hashIntArray(int seed, int... intArray) {
return hash(seed, intArray);
}
/**
* Calculates hash code for short array.
*/
public static int hash(int seed, short[] shortArray) {
if (shortArray == null) {
return 0;
}
for (short aShort : shortArray) {
seed = hash(seed, aShort);
}
return seed;
}
/**
* Calculates hash code for short array.
*/
public static int hashShortArray(int seed, short... shortArray) {
return hash(seed, shortArray);
}
/**
* Calculates hash code for byte array.
*/
public static int hash(int seed, byte[] byteArray) {
if (byteArray == null) {
return 0;
}
for (byte aByte : byteArray) {
seed = hash(seed, aByte);
}
return seed;
}
/**
* Calculates hash code for byte array.
*/
public static int hashByteArray(int seed, byte... byteArray) {
return hash(seed, byteArray);
}
// ---------------------------------------------------------------- long
/**
* Calculates hash code for longs.
*/
public static int hash(int seed, long aLong) {
return (PRIME * seed) + (int) (aLong ^ (aLong >>> 32));
}
/**
* Calculates hash code for long array.
*/
public static int hash(int seed, long[] longArray) {
if (longArray == null) {
return 0;
}
for (long aLong : longArray) {
seed = hash(seed, aLong);
}
return seed;
}
/**
* Calculates hash code for long array.
*/
public static int hashLongArray(int seed, long... longArray) {
return hash(seed, longArray);
}
// ---------------------------------------------------------------- float
/**
* Calculates hash code for floats.
*/
public static int hash(int seed, float aFloat) {
return hash(seed, Float.floatToIntBits(aFloat));
}
/**
* Calculates hash code for float array.
*/
public static int hash(int seed, float[] floatArray) {
if (floatArray == null) {
return 0;
}
for (float aFloat : floatArray) {
seed = hash(seed, aFloat);
}
return seed;
}
/**
* Calculates hash code for float array.
*/
public static int hashFloatArray(int seed, float... floatArray) {
return hash(seed, floatArray);
}
// ---------------------------------------------------------------- double
/**
* Calculates hash code for doubles.
*/
public static int hash(int seed, double aDouble) {
return hash(seed, Double.doubleToLongBits(aDouble));
}
/**
* Calculates hash code for double array.
*/
public static int hash(int seed, double[] doubleArray) {
if (doubleArray == null) {
return 0;
}
for (double aDouble : doubleArray) {
seed = hash(seed, aDouble);
}
return seed;
}
/**
* Calculates hash code for double array.
*/
public static int hashDoubleArray(int seed, double... doubleArray) {
return hash(seed, doubleArray);
}
// ---------------------------------------------------------------- object
/**
* Calculates hash code for Objects. Object is a possibly-null object field, and possibly an array.
* <p>
* If aObject is an array, then each element may be a primitive
* or a possibly-null object.
*/
public static int hash(int seed, Object aObject) {
int result = seed;
if (aObject == null) {
result = hash(result, 0);
} else if (aObject.getClass().isArray() == false) {
result = hash(result, aObject.hashCode());
} else {
Object[] objects = (Object[]) aObject;
int length = objects.length;
for (int idx = 0; idx < length; ++idx) {
result = hash(result, objects[idx]);
}
}
return result;
}
}
</source>
Get hash code for primitive data types
<source lang="java">
import java.lang.reflect.Array; import java.util.Arrays; /*
* Copyright 2002-2007 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
//Revised from springframework /**
* Miscellaneous object utility methods. Mainly for internal use within the * framework; consider Jakarta"s Commons Lang for a more comprehensive suite * of object utilities. * * @author Juergen Hoeller * @author Keith Donald * @author Rod Johnson * @author Rob Harrop * @author Alex Ruiz * @since 19.03.2004 * @see org.apache.rumons.lang.ObjectUtils */
abstract class ObjectUtils {
private static final int INITIAL_HASH = 7;
private static final int MULTIPLIER = 31;
private static final String EMPTY_STRING = "";
private static final String NULL_STRING = "null";
private static final String ARRAY_START = "{";
private static final String ARRAY_END = "}";
private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
private static final String ARRAY_ELEMENT_SEPARATOR = ", ";
/** * Return the same value as{@link Boolean#hashCode()}. * @see Boolean#hashCode() */ public static int hashCode(boolean bool) { return bool ? 1231 : 1237; } /** * Return the same value as{@link Double#hashCode()}. * @see Double#hashCode() */ public static int hashCode(double dbl) { long bits = Double.doubleToLongBits(dbl); return hashCode(bits); } /** * Return the same value as{@link Float#hashCode()}. * @see Float#hashCode() */ public static int hashCode(float flt) { return Float.floatToIntBits(flt); } /** * Return the same value as{@link Long#hashCode()}. * @see Long#hashCode() */ public static int hashCode(long lng) { return (int) (lng ^ (lng >>> 32)); }
}
</source>
Gets the hash code of an object returning zero when the object is null
<source lang="java">
/*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
import java.io.Serializable; /**
* <p>Operations onObject.
**
This class tries to handle null input gracefully.
* An exception will generally not be thrown for a null input.
* Each method documents its behaviour in more detail.
* * @author * @since 1.0 * @version $Id: ObjectUtils.java 594336 2007-11-12 22:54:02Z bayard $ */
public class ObjectUtils {
/***
Singleton used as a null placeholder where
* null has another meaning.
**
For example, in a HashMap the
* {@link java.util.HashMap#get(java.lang.Object)} method returns
* null if the Map contains
* null or if there is no matching key. The
* Null placeholder can be used to distinguish between
* these two cases.
**
Another example is Hashtable, where null
* cannot be stored.
**
This instance is Serializable.
*/ public static final Null NULL = new Null(); /***
ObjectUtils instances should NOT be constructed in
* standard programming. Instead, the class should be used as
* ObjectUtils.defaultIfNull("a","b");.
**
This constructor is public to permit tools that require a JavaBean instance * to operate.
*/
public ObjectUtils() {
super();
}
// Defaulting
//-----------------------------------------------------------------------
/**
* Returns a default value if the object passed is
* null.
**
* ObjectUtils.defaultIfNull(null, null) = null
* ObjectUtils.defaultIfNull(null, "") = ""
* ObjectUtils.defaultIfNull(null, "zz") = "zz"
* ObjectUtils.defaultIfNull("abc", *) = "abc"
* ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE
*
*
* @param object the Object to test, may be null
* @param defaultValue the default value to return, may be null
* @return object if it is not null, defaultValue otherwise
*/
public static Object defaultIfNull(Object object, Object defaultValue) {
return object != null ? object : defaultValue;
}
/**
* Compares two objects for equality, where either one or both
* objects may be null.
**
* ObjectUtils.equals(null, null) = true
* ObjectUtils.equals(null, "") = false
* ObjectUtils.equals("", null) = false
* ObjectUtils.equals("", "") = true
* ObjectUtils.equals(Boolean.TRUE, null) = false
* ObjectUtils.equals(Boolean.TRUE, "true") = false
* ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE) = true
* ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
*
*
* @param object1 the first object, may be null
* @param object2 the second object, may be null
* @return true if the values of both objects are the same
*/
public static boolean equals(Object object1, Object object2) {
if (object1 == object2) {
return true;
}
if ((object1 == null) || (object2 == null)) {
return false;
}
return object1.equals(object2);
}
/**
* Gets the hash code of an object returning zero when the
* object is null.
**
* ObjectUtils.hashCode(null) = 0
* ObjectUtils.hashCode(obj) = obj.hashCode()
*
*
* @param obj the object to obtain the hash code of, may be null
* @return the hash code of the object, or zero if null
* @since 2.1
*/
public static int hashCode(Object obj) {
return (obj == null) ? 0 : obj.hashCode();
}
// Identity ToString
//-----------------------------------------------------------------------
/**
* Gets the toString that would be produced by Object
* if a class did not override toString itself. null
* will return null.
**
* ObjectUtils.identityToString(null) = null
* ObjectUtils.identityToString("") = "java.lang.String@1e23"
* ObjectUtils.identityToString(Boolean.TRUE) = "java.lang.Boolean@7fa"
*
*
* @param object the object to create a toString for, may be
* null
* @return the default toString text, or null if
* null passed in
*/
public static String identityToString(Object object) {
if (object == null) {
return null;
}
StringBuffer buffer = new StringBuffer();
identityToString(buffer, object);
return buffer.toString();
}
/**
* Appends the toString that would be produced by Object
* if a class did not override toString itself. null
* will throw a NullPointerException for either of the two parameters.
**
* ObjectUtils.identityToString(buf, "") = buf.append("java.lang.String@1e23"
* ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa"
* ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")
*
*
* @param buffer the buffer to append to
* @param object the object to create a toString for
* @since 2.4
*/
public static void identityToString(StringBuffer buffer, Object object) {
if (object == null) {
throw new NullPointerException("Cannot get the toString of a null identity");
}
buffer.append(object.getClass().getName())
.append("@")
.append(Integer.toHexString(System.identityHashCode(object)));
}
// ToString //----------------------------------------------------------------------- /***
Gets the toString of an Object returning
* an empty string ("") if null input.
**
* ObjectUtils.toString(null) = ""
* ObjectUtils.toString("") = ""
* ObjectUtils.toString("bat") = "bat"
* ObjectUtils.toString(Boolean.TRUE) = "true"
*
*
* @see StringUtils#defaultString(String)
* @see String#valueOf(Object)
* @param obj the Object to toString, may be null
* @return the passed in Object"s toString, or nullStr if null input
* @since 2.0
*/
public static String toString(Object obj) {
return obj == null ? "" : obj.toString();
}
/**
* Gets the toString of an Object returning
* a specified text if null input.
**
* ObjectUtils.toString(null, null) = null
* ObjectUtils.toString(null, "null") = "null"
* ObjectUtils.toString("", "null") = ""
* ObjectUtils.toString("bat", "null") = "bat"
* ObjectUtils.toString(Boolean.TRUE, "null") = "true"
*
*
* @see StringUtils#defaultString(String,String)
* @see String#valueOf(Object)
* @param obj the Object to toString, may be null
* @param nullStr the String to return if null input, may be null
* @return the passed in Object"s toString, or nullStr if null input
* @since 2.0
*/
public static String toString(Object obj, String nullStr) {
return obj == null ? nullStr : obj.toString();
}
// Null //----------------------------------------------------------------------- /***
Class used as a null placeholder where null
* has another meaning.
**
For example, in a HashMap the
* {@link java.util.HashMap#get(java.lang.Object)} method returns
* null if the Map contains
* null or if there is no matching key. The
* Null placeholder can be used to distinguish between
* these two cases.
**
Another example is Hashtable, where null
* cannot be stored.
*/
public static class Null implements Serializable {
/**
* Required for serialization support. Declare serialization compatibility with Commons Lang 1.0
*
* @see java.io.Serializable
*/
private static final long serialVersionUID = 7092611880189329093L;
/**
* Restricted constructor - singleton.
*/
Null() {
super();
}
/**
* Ensure singleton.
*
* @return the singleton value
*/
private Object readResolve() {
return ObjectUtils.NULL;
}
}
}
</source>
Hash 32 String
<source lang="java">
/*
GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Contact info: lobochief@users.sourceforge.net
- /
import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; public class Strings {
private static final MessageDigest MESSAGE_DIGEST;
public static final String[] EMPTY_ARRAY = new String[0];
static {
MessageDigest md;
try {
md = MessageDigest.getInstance("MD5");
} catch(NoSuchAlgorithmException err) {
throw new IllegalStateException();
}
MESSAGE_DIGEST = md;
}
private static final String HEX_CHARS = "0123456789ABCDEF";
public static String getMD5(String source) {
byte[] bytes;
try {
bytes = source.getBytes("UTF-8");
} catch(java.io.UnsupportedEncodingException ue) {
throw new IllegalStateException(ue);
}
byte[] result;
synchronized(MESSAGE_DIGEST) {
MESSAGE_DIGEST.update(bytes);
result = MESSAGE_DIGEST.digest();
}
char[] resChars = new char[32];
int len = result.length;
for(int i = 0; i < len; i++) {
byte b = result[i];
int lo4 = b & 0x0F;
int hi4 = (b & 0xF0) >> 4;
resChars[i*2] = HEX_CHARS.charAt(hi4);
resChars[i*2 + 1] = HEX_CHARS.charAt(lo4);
}
return new String(resChars);
}
public static String getHash32(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 8);
}
public static String getHash64(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 16);
}
}
</source>
Hash 64 String
<source lang="java">
/*
GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Contact info: lobochief@users.sourceforge.net
- /
import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; public class Strings {
private static final MessageDigest MESSAGE_DIGEST;
public static final String[] EMPTY_ARRAY = new String[0];
static {
MessageDigest md;
try {
md = MessageDigest.getInstance("MD5");
} catch(NoSuchAlgorithmException err) {
throw new IllegalStateException();
}
MESSAGE_DIGEST = md;
}
private static final String HEX_CHARS = "0123456789ABCDEF";
public static String getMD5(String source) {
byte[] bytes;
try {
bytes = source.getBytes("UTF-8");
} catch(java.io.UnsupportedEncodingException ue) {
throw new IllegalStateException(ue);
}
byte[] result;
synchronized(MESSAGE_DIGEST) {
MESSAGE_DIGEST.update(bytes);
result = MESSAGE_DIGEST.digest();
}
char[] resChars = new char[32];
int len = result.length;
for(int i = 0; i < len; i++) {
byte b = result[i];
int lo4 = b & 0x0F;
int hi4 = (b & 0xF0) >> 4;
resChars[i*2] = HEX_CHARS.charAt(hi4);
resChars[i*2 + 1] = HEX_CHARS.charAt(lo4);
}
return new String(resChars);
}
public static String getHash32(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 8);
}
public static String getHash64(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 16);
}
}
</source>
Hash Code Builder
<source lang="java">
/*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
import java.lang.reflect.Field; import java.lang.reflect.Modifier; /**
* HashCode generation routines.
* * This class enables a good hashcode to be built for any class. It follows * the rules laid out in the book Effective Java, by Joshua Bloch. Writing a * good hashCode is actually quite difficult. This class aims to simplify the * process. * <p> * All relevant fields from the object should be included in the hashCode. Derived * fields may be excluded. In general, any field used in the equals method must be * used in the hashCode method. * <p> * To use this class write code as follows: *
* public class Person {
* String name;
* int age;
* boolean isSmoker;
* ...
*
* public int hashCode() {
* // you pick a hard-coded, randomly chosen, non-zero, odd number
* // ideally different for each class
* return new HashCodeBuilder(17, 37).
* append(name).
* append(age).
* append(smoker).
* toHashCode();
* }
* }
*
* <p> * Alternatively, there is a method that uses reflection to determine * the fields to test. Because these fields are usually private, the method, **reflectionHashCode, usesField.setAccessibleto * change the visibility of the fields. This will fail under a security manager, * unless the appropriate permissions are set. It is also slower than testing * explicitly. * <p> * A typical invocation for this method would look like:
* public boolean hashCode(Object o) {
* return HashCodeBuilder.reflectionHashCode(this);
* }
*
* * @author * @version $Id: HashCodeBuilder.java 517121 2007-03-12 07:45:49Z ate $ */
public class HashCodeBuilder {
/**
* Constant to use in building the hashCode
*/
private final int iConstant;
/**
* Running total of the hashCode
*/
private int iTotal = 0;
/**
* Constructor for HashCodeBuilder.
* This constructor uses two hard coded choices for the constants needed
* to build a hashCode.
*/
public HashCodeBuilder()
{
super();
iConstant = 37;
iTotal = 17;
}
/**
* Constructor for HashCodeBuilder.
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber a non-zero, odd number used as the initial value
* @param multiplierNonZeroOddNumber a non-zero, odd number used as the multiplier
* @throws IllegalArgumentException if the number is zero or even
*/
public HashCodeBuilder(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber)
{
super();
if (initialNonZeroOddNumber == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires a non zero initial value");
}
if (initialNonZeroOddNumber % 2 == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires an odd initial value");
}
if (multiplierNonZeroOddNumber == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires a non zero multiplier");
}
if (multiplierNonZeroOddNumber % 2 == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires an odd multiplier");
}
iConstant = multiplierNonZeroOddNumber;
iTotal = initialNonZeroOddNumber;
}
//-------------------------------------------------------------------------
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* Transient members will be not be used, as they are likely derived
* fields, and not part of the value of the object.
* Static fields will not be tested.
* This constructor uses two hard coded choices for the constants needed
* to build a hash code.
*
* @param object the object to create a hash code for
* @return int hash code
* @throws IllegalArgumentException if the object is null
*/
public static int reflectionHashCode(Object object)
{
return reflectionHashCode(object, false);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* If the TestTransients parameter is set to true, transient members will be
* tested, otherwise they are ignored, as they are likely derived fields, and
* not part of the value of the object.
* Static fields will not be tested.
* This constructor uses two hard coded choices for the constants needed
* to build a hash code.
*
* @param object the object to create a hash code for
* @param testTransients whether to include transient fields
* @return int hash code
* @throws IllegalArgumentException if the object is null
*/
public static int reflectionHashCode(Object object, boolean testTransients)
{
return reflectionHashCode(17, 37, object, testTransients);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* Transient members will be not be used, as they are likely derived
* fields, and not part of the value of the object.
* Static fields will not be tested.
* <p>
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber a non-zero, odd number used as the initial value
* @param multiplierNonZeroOddNumber a non-zero, odd number used as the multiplier
* @param object the object to create a hash code for
* @return int hash code
* @throws IllegalArgumentException if the object is null
* @throws IllegalArgumentException if the number is zero or even
*/
public static int reflectionHashCode(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber, Object object)
{
return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, false);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* If the TestTransients parameter is set to true, transient members will be
* tested, otherwise they are ignored, as they are likely derived fields, and
* not part of the value of the object.
* Static fields will not be tested.
* <p>
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber
* @param multiplierNonZeroOddNumber
* @param object the object to create a hash code for
* @param testTransients whether to include transient fields
* @return int hash code
* @throws IllegalArgumentException if the object is null
* @throws IllegalArgumentException if the number is zero or even
*/
public static int reflectionHashCode(
int initialNonZeroOddNumber,
int multiplierNonZeroOddNumber,
Object object,
boolean testTransients)
{
if (object == null)
{
throw new IllegalArgumentException("The object to build a hash code for must not be null");
}
HashCodeBuilder hashCodeBuilder = new HashCodeBuilder(initialNonZeroOddNumber, multiplierNonZeroOddNumber);
Field[] fields = object.getClass().getDeclaredFields();
Field.setAccessible(fields, true);
for (int i = 0; i < fields.length; ++i)
{
Field f = fields[i];
if (testTransients || !Modifier.isTransient(f.getModifiers()))
{
if (!Modifier.isStatic(f.getModifiers()))
{
try
{
hashCodeBuilder.append(f.get(object));
}
catch (IllegalAccessException e)
{
//this can"t happen. Would get a Security exception instead
//throw a runtime exception in case the impossible happens.
throw new InternalError("Unexpected IllegalAccessException");
}
}
}
}
return hashCodeBuilder.toHashCode();
}
//-------------------------------------------------------------------------
/**
* Append a hashCode for an Object.
*
* @param object the object to add to the hashCode
* @return this
*/
public HashCodeBuilder append(Object object)
{
if (object == null)
{
iTotal = iTotal * iConstant;
}
else
{
if (object.getClass().isArray() == false)
{
//the simple case, not an array, just the element
iTotal = iTotal * iConstant + object.hashCode();
}
else
{
//"Switch" on type of array, to dispatch to the correct handler
// This handles multi dimensional arrays
if (object instanceof long[])
{
append((long[]) object);
}
else if (object instanceof int[])
{
append((int[]) object);
}
else if (object instanceof short[])
{
append((short[]) object);
}
else if (object instanceof char[])
{
append((char[]) object);
}
else if (object instanceof byte[])
{
append((byte[]) object);
}
else if (object instanceof double[])
{
append((double[]) object);
}
else if (object instanceof float[])
{
append((float[]) object);
}
else if (object instanceof boolean[])
{
append((boolean[]) object);
}
else
{
// Not an array of primitives
append((Object[]) object);
}
}
}
return this;
}
/**
* Append a hashCode for a long.
*
* @param value the long to add to the hashCode
* @return this
*/
public HashCodeBuilder append(long value)
{
iTotal = iTotal * iConstant + ((int) (value ^ (value >> 32)));
return this;
}
/**
* Append a hashCode for an int.
*
* @param value the int to add to the hashCode
* @return this
*/
public HashCodeBuilder append(int value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a short.
*
* @param value the short to add to the hashCode
* @return this
*/
public HashCodeBuilder append(short value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a char.
*
* @param value the char to add to the hashCode
* @return this
*/
public HashCodeBuilder append(char value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a byte.
*
* @param value the byte to add to the hashCode
* @return this
*/
public HashCodeBuilder append(byte value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a double.
*
* @param value the double to add to the hashCode
* @return this
*/
public HashCodeBuilder append(double value)
{
return append(Double.doubleToLongBits(value));
}
/**
* Append a hashCode for a float.
*
* @param value the float to add to the hashCode
* @return this
*/
public HashCodeBuilder append(float value)
{
iTotal = iTotal * iConstant + Float.floatToIntBits(value);
return this;
}
/**
* Append a hashCode for a long.
*
* @param value the long to add to the hashCode
* @return this
*/
public HashCodeBuilder append(boolean value)
{
iTotal = iTotal * iConstant + (value ? 0 : 1);
return this;
}
/**
* Append a hashCode for an Object array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(Object[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a long array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(long[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for an int array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(int[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a short array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(short[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a char array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(char[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a byte array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(byte[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a double array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(double[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a float array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(float[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a boolean array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(boolean[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Return the computed hashCode
*
* @return int hashCode based on the fields appended
*/
public int toHashCode()
{
return iTotal;
}
}
</source>
HashCode generation
<source lang="java">
/*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
import java.lang.reflect.Field; import java.lang.reflect.Modifier; /**
* HashCode generation routines.
* <p>
* This class enables a good hashcode to be built for any class. It follows
* the rules laid out in the book Effective Java, by Joshua Bloch. Writing a
* good hashCode is actually quite difficult. This class aims to simplify the
* process.
* <p>
* All relevant fields from the object should be included in the hashCode. Derived
* fields may be excluded. In general, any field used in the equals method must be
* used in the hashCode method.
* <p>
* To use this class write code as follows:
*
* public class Person {
* String name;
* int age;
* boolean isSmoker;
* ...
*
* public int hashCode() {
* // you pick a hard-coded, randomly chosen, non-zero, odd number
* // ideally different for each class
* return new HashCodeBuilder(17, 37).
* append(name).
* append(age).
* append(smoker).
* toHashCode();
* }
* }
*
* <p> * Alternatively, there is a method that uses reflection to determine * the fields to test. Because these fields are usually private, the method, **reflectionHashCode, usesField.setAccessibleto * change the visibility of the fields. This will fail under a security manager, * unless the appropriate permissions are set. It is also slower than testing * explicitly. * <p> * A typical invocation for this method would look like:
* public boolean hashCode(Object o) {
* return HashCodeBuilder.reflectionHashCode(this);
* }
*
* * @author * @version $Id: HashCodeBuilder.java 517121 2007-03-12 07:45:49Z ate $ */
public class HashCodeBuilder {
/**
* Constant to use in building the hashCode
*/
private final int iConstant;
/**
* Running total of the hashCode
*/
private int iTotal = 0;
/**
* Constructor for HashCodeBuilder.
* This constructor uses two hard coded choices for the constants needed
* to build a hashCode.
*/
public HashCodeBuilder()
{
super();
iConstant = 37;
iTotal = 17;
}
/**
* Constructor for HashCodeBuilder.
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber a non-zero, odd number used as the initial value
* @param multiplierNonZeroOddNumber a non-zero, odd number used as the multiplier
* @throws IllegalArgumentException if the number is zero or even
*/
public HashCodeBuilder(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber)
{
super();
if (initialNonZeroOddNumber == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires a non zero initial value");
}
if (initialNonZeroOddNumber % 2 == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires an odd initial value");
}
if (multiplierNonZeroOddNumber == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires a non zero multiplier");
}
if (multiplierNonZeroOddNumber % 2 == 0)
{
throw new IllegalArgumentException("HashCodeBuilder requires an odd multiplier");
}
iConstant = multiplierNonZeroOddNumber;
iTotal = initialNonZeroOddNumber;
}
//-------------------------------------------------------------------------
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* Transient members will be not be used, as they are likely derived
* fields, and not part of the value of the object.
* Static fields will not be tested.
* This constructor uses two hard coded choices for the constants needed
* to build a hash code.
*
* @param object the object to create a hash code for
* @return int hash code
* @throws IllegalArgumentException if the object is null
*/
public static int reflectionHashCode(Object object)
{
return reflectionHashCode(object, false);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* If the TestTransients parameter is set to true, transient members will be
* tested, otherwise they are ignored, as they are likely derived fields, and
* not part of the value of the object.
* Static fields will not be tested.
* This constructor uses two hard coded choices for the constants needed
* to build a hash code.
*
* @param object the object to create a hash code for
* @param testTransients whether to include transient fields
* @return int hash code
* @throws IllegalArgumentException if the object is null
*/
public static int reflectionHashCode(Object object, boolean testTransients)
{
return reflectionHashCode(17, 37, object, testTransients);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* Transient members will be not be used, as they are likely derived
* fields, and not part of the value of the object.
* Static fields will not be tested.
* <p>
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber a non-zero, odd number used as the initial value
* @param multiplierNonZeroOddNumber a non-zero, odd number used as the multiplier
* @param object the object to create a hash code for
* @return int hash code
* @throws IllegalArgumentException if the object is null
* @throws IllegalArgumentException if the number is zero or even
*/
public static int reflectionHashCode(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber, Object object)
{
return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, false);
}
/**
* This method uses reflection to build a valid hash code.
* <p>
* It uses Field.setAccessible to gain access to private fields. This means
* that it will throw a security exception if run under a security manger, if
* the permissions are not set up.
* It is also not as efficient as testing explicitly.
* If the TestTransients parameter is set to true, transient members will be
* tested, otherwise they are ignored, as they are likely derived fields, and
* not part of the value of the object.
* Static fields will not be tested.
* <p>
* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally
* these should be different for each class, however this is not vital.
* Prime numbers are preferred, especially for the multiplier.
*
* @param initialNonZeroOddNumber
* @param multiplierNonZeroOddNumber
* @param object the object to create a hash code for
* @param testTransients whether to include transient fields
* @return int hash code
* @throws IllegalArgumentException if the object is null
* @throws IllegalArgumentException if the number is zero or even
*/
public static int reflectionHashCode(
int initialNonZeroOddNumber,
int multiplierNonZeroOddNumber,
Object object,
boolean testTransients)
{
if (object == null)
{
throw new IllegalArgumentException("The object to build a hash code for must not be null");
}
HashCodeBuilder hashCodeBuilder = new HashCodeBuilder(initialNonZeroOddNumber, multiplierNonZeroOddNumber);
Field[] fields = object.getClass().getDeclaredFields();
Field.setAccessible(fields, true);
for (int i = 0; i < fields.length; ++i)
{
Field f = fields[i];
if (testTransients || !Modifier.isTransient(f.getModifiers()))
{
if (!Modifier.isStatic(f.getModifiers()))
{
try
{
hashCodeBuilder.append(f.get(object));
}
catch (IllegalAccessException e)
{
//this can"t happen. Would get a Security exception instead
//throw a runtime exception in case the impossible happens.
throw new InternalError("Unexpected IllegalAccessException");
}
}
}
}
return hashCodeBuilder.toHashCode();
}
//-------------------------------------------------------------------------
/**
* Append a hashCode for an Object.
*
* @param object the object to add to the hashCode
* @return this
*/
public HashCodeBuilder append(Object object)
{
if (object == null)
{
iTotal = iTotal * iConstant;
}
else
{
if (object.getClass().isArray() == false)
{
//the simple case, not an array, just the element
iTotal = iTotal * iConstant + object.hashCode();
}
else
{
//"Switch" on type of array, to dispatch to the correct handler
// This handles multi dimensional arrays
if (object instanceof long[])
{
append((long[]) object);
}
else if (object instanceof int[])
{
append((int[]) object);
}
else if (object instanceof short[])
{
append((short[]) object);
}
else if (object instanceof char[])
{
append((char[]) object);
}
else if (object instanceof byte[])
{
append((byte[]) object);
}
else if (object instanceof double[])
{
append((double[]) object);
}
else if (object instanceof float[])
{
append((float[]) object);
}
else if (object instanceof boolean[])
{
append((boolean[]) object);
}
else
{
// Not an array of primitives
append((Object[]) object);
}
}
}
return this;
}
/**
* Append a hashCode for a long.
*
* @param value the long to add to the hashCode
* @return this
*/
public HashCodeBuilder append(long value)
{
iTotal = iTotal * iConstant + ((int) (value ^ (value >> 32)));
return this;
}
/**
* Append a hashCode for an int.
*
* @param value the int to add to the hashCode
* @return this
*/
public HashCodeBuilder append(int value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a short.
*
* @param value the short to add to the hashCode
* @return this
*/
public HashCodeBuilder append(short value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a char.
*
* @param value the char to add to the hashCode
* @return this
*/
public HashCodeBuilder append(char value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a byte.
*
* @param value the byte to add to the hashCode
* @return this
*/
public HashCodeBuilder append(byte value)
{
iTotal = iTotal * iConstant + value;
return this;
}
/**
* Append a hashCode for a double.
*
* @param value the double to add to the hashCode
* @return this
*/
public HashCodeBuilder append(double value)
{
return append(Double.doubleToLongBits(value));
}
/**
* Append a hashCode for a float.
*
* @param value the float to add to the hashCode
* @return this
*/
public HashCodeBuilder append(float value)
{
iTotal = iTotal * iConstant + Float.floatToIntBits(value);
return this;
}
/**
* Append a hashCode for a long.
*
* @param value the long to add to the hashCode
* @return this
*/
public HashCodeBuilder append(boolean value)
{
iTotal = iTotal * iConstant + (value ? 0 : 1);
return this;
}
/**
* Append a hashCode for an Object array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(Object[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a long array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(long[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for an int array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(int[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a short array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(short[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a char array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(char[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a byte array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(byte[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a double array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(double[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a float array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(float[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Append a hashCode for a boolean array.
*
* @param array the array to add to the hashCode
* @return this
*/
public HashCodeBuilder append(boolean[] array)
{
if (array == null)
{
iTotal = iTotal * iConstant;
}
else
{
for (int i = 0; i < array.length; i++)
{
append(array[i]);
}
}
return this;
}
/**
* Return the computed hashCode
*
* @return int hashCode based on the fields appended
*/
public int toHashCode()
{
return iTotal;
}
}
</source>
MD5 hash generator
<source lang="java">
/*
* written Santeri Paavolainen, Helsinki Finland 1996 * (c) Santeri Paavolainen, Helsinki Finland 1996 * modifications Copyright (C) 2002-2007 Stephen Ostermiller * http://ostermiller.org/contact.pl?regarding=Java+Utilities * Copyright (C) 2007 Stu Thompson stu.rup -at- mailworks.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * See COPYING.TXT for details. * * The original work by Santeri Paavolainen can be found at * http://www.helsinki.fi/~sjpaavol/programs/md5/ * * This Java class has been derived from the RSA Data Security, Inc. MD5 * Message-Digest Algorithm and its reference implementation. */
import java.io.*; /**
* MD5 hash generator. * More information about this class is available from . * <p> * This class takes as input a message of arbitrary length and produces * as output a 128-bit "fingerprint" or "message digest" of the input. * It is conjectured that it is computationally infeasible to produce * two messages having the same message digest, or to produce any * message having a given pre-specified target message digest. The MD5 * algorithm is intended for digital signature applications, where a * large file must be "compressed" in a secure manner before being * encrypted with a private (secret) key under a public-key cryptosystem * such as RSA. * <p> * For more information see RFC1321. * * @see MD5OutputStream * @see MD5InputStream * * @author Santeri Paavolainen http://www.helsinki.fi/~sjpaavol/programs/md5/ * @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities * @since ostermillerutils 1.00.00 */
public class MD5 {
/**
* Class constructor
*
* @since ostermillerutils 1.00.00
*/
public MD5 () {
reset();
}
/**
* Command line program that will take files as arguments
* and output the MD5 sum for each file.
*
* @param args command line arguments
*
* @since ostermillerutils 1.00.00
*/
public static void main (String[] args){
if (args.length == 0){
System.err.println("Please specify a file.");
} else {
for (String element: args) {
try {
System.out.println(MD5.getHashString(new File(element)) + " " + element);
} catch (IOException x){
System.err.println(x.getMessage());
}
}
}
}
/**
* Gets this hash sum as an array of 16 bytes.
*
* @return Array of 16 bytes, the hash of all updated bytes.
*
* @since ostermillerutils 1.00.00
*/
public byte[] getHash() {
if (!finalState.valid) {
finalState.copy(workingState);
long bitCount = finalState.bitCount;
// Compute the number of left over bits
int leftOver = (int) (((bitCount >>> 3)) & 0x3f);
// Compute the amount of padding to add based on number of left over bits.
int padlen = (leftOver < 56) ? (56 - leftOver) : (120 - leftOver);
// add the padding
update(finalState, padding, 0, padlen);
// add the length (computed before padding was added)
update(finalState, encode(bitCount), 0, 8);
finalState.valid = true;
}
// make a copy of the hash before returning it.
return encode(finalState.state, 16);
}
/**
* Returns 32-character hex representation of this hash.
*
* @return String representation of this object"s hash.
*
* @since ostermillerutils 1.00.00
*/
public String getHashString(){
return toHex(this.getHash());
}
/**
* Gets the MD5 hash of the given byte array.
*
* @param b byte array for which an MD5 hash is desired.
* @return Array of 16 bytes, the hash of all updated bytes.
*
* @since ostermillerutils 1.00.00
*/
public static byte[] getHash(byte[] b){
MD5 md5 = new MD5();
md5.update(b);
return md5.getHash();
}
/**
* Gets the MD5 hash of the given byte array.
*
* @param b byte array for which an MD5 hash is desired.
* @return 32-character hex representation the data"s MD5 hash.
*
* @since ostermillerutils 1.00.00
*/
public static String getHashString(byte[] b){
MD5 md5 = new MD5();
md5.update(b);
return md5.getHashString();
}
/**
* Gets the MD5 hash the data on the given InputStream.
*
* @param in byte array for which an MD5 hash is desired.
* @return Array of 16 bytes, the hash of all updated bytes.
* @throws IOException if an I/O error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static byte[] getHash(InputStream in) throws IOException {
MD5 md5 = new MD5();
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1){
md5.update(buffer, read);
}
return md5.getHash();
}
/**
* Gets the MD5 hash the data on the given InputStream.
*
* @param in byte array for which an MD5 hash is desired.
* @return 32-character hex representation the data"s MD5 hash.
* @throws IOException if an I/O error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static String getHashString(InputStream in) throws IOException {
MD5 md5 = new MD5();
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1){
md5.update(buffer, read);
}
return md5.getHashString();
}
/**
* Gets the MD5 hash of the given file.
*
* @param f file for which an MD5 hash is desired.
* @return Array of 16 bytes, the hash of all updated bytes.
* @throws IOException if an I/O error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static byte[] getHash(File f) throws IOException {
InputStream is = new FileInputStream(f);
byte[] hash = getHash(is);
is.close();
return hash;
}
/**
* Gets the MD5 hash of the given file.
*
* @param f file array for which an MD5 hash is desired.
* @return 32-character hex representation the data"s MD5 hash.
* @throws IOException if an I/O error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static String getHashString(File f) throws IOException {
InputStream is = new FileInputStream(f);
String hash = getHashString(is);
is.close();
return hash;
}
/**
* Gets the MD5 hash of the given String.
* The string is converted to bytes using the current
* platform"s default character encoding.
*
* @param s String for which an MD5 hash is desired.
* @return Array of 16 bytes, the hash of all updated bytes.
*
* @since ostermillerutils 1.00.00
*/
public static byte[] getHash(String s){
MD5 md5 = new MD5();
md5.update(s);
return md5.getHash();
}
/**
* Gets the MD5 hash of the given String.
* The string is converted to bytes using the current
* platform"s default character encoding.
*
* @param s String for which an MD5 hash is desired.
* @return 32-character hex representation the data"s MD5 hash.
*
* @since ostermillerutils 1.00.00
*/
public static String getHashString(String s){
MD5 md5 = new MD5();
md5.update(s);
return md5.getHashString();
}
/**
* Gets the MD5 hash of the given String.
*
* @param s String for which an MD5 hash is desired.
* @param enc The name of a supported character encoding.
* @return Array of 16 bytes, the hash of all updated bytes.
* @throws UnsupportedEncodingException If the named encoding is not supported.
*
* @since ostermillerutils 1.00.00
*/
public static byte[] getHash(String s, String enc) throws UnsupportedEncodingException {
MD5 md5 = new MD5();
md5.update(s, enc);
return md5.getHash();
}
/**
* Gets the MD5 hash of the given String.
*
* @param s String for which an MD5 hash is desired.
* @param enc The name of a supported character encoding.
* @return 32-character hex representation the data"s MD5 hash.
* @throws UnsupportedEncodingException If the named encoding is not supported.
*
* @since ostermillerutils 1.00.00
*/
public static String getHashString(String s, String enc) throws UnsupportedEncodingException {
MD5 md5 = new MD5();
md5.update(s, enc);
return md5.getHashString();
}
/**
* Reset the MD5 sum to its initial state.
*
* @since ostermillerutils 1.00.00
*/
public void reset() {
workingState.reset();
finalState.valid = false;
}
/**
* Returns 32-character hex representation of this hash.
*
* @return String representation of this object"s hash.
*
* @since ostermillerutils 1.00.00
*/
@Override public String toString(){
return getHashString();
}
/**
* Update this hash with the given data.
* <p>
* A state may be passed into this method so that we can add padding
* and finalize a md5 hash without limiting our ability to update
* more data later.
* <p>
* If length bytes are not available to be hashed, as many bytes as
* possible will be hashed.
*
* @param state Which state is updated.
* @param buffer Array of bytes to be hashed.
* @param offset Offset to buffer array.
* @param length number of bytes to hash.
*
* @since ostermillerutils 1.00.00
*/
private void update (MD5State state, byte buffer[], int offset, int length) {
finalState.valid = false;
// if length goes beyond the end of the buffer, cut it short.
if ((length + offset) > buffer.length){
length = buffer.length - offset;
}
// compute number of bytes mod 64
// this is what we have sitting in a buffer
// that have not been hashed yet
int index = (int) (state.bitCount >>> 3) & 0x3f;
// add the length to the count (translate bytes to bits)
state.bitCount += length << 3;
int partlen = 64 - index;
int i = 0;
if (length >= partlen) {
System.arraycopy(buffer, offset, state.buffer, index, partlen);
transform(state, decode(state.buffer, 64, 0));
for (i = partlen; (i + 63) < length; i+= 64){
transform(state, decode(buffer, 64, i));
}
index = 0;
}
// buffer remaining input
if (i < length) {
for (int start = i; i < length; i++) {
state.buffer[index + i - start] = buffer[i + offset];
}
}
}
/**
* Update this hash with the given data.
* <p>
* If length bytes are not available to be hashed, as many bytes as
* possible will be hashed.
*
* @param buffer Array of bytes to be hashed.
* @param offset Offset to buffer array.
* @param length number of bytes to hash.
*
* @since ostermillerutils 1.00.00
*/
public void update (byte buffer[], int offset, int length) {
update(workingState, buffer, offset, length);
}
/**
* Update this hash with the given data.
* <p>
* If length bytes are not available to be hashed, as many bytes as
* possible will be hashed.
*
* @param buffer Array of bytes to be hashed.
* @param length number of bytes to hash.
*
* @since ostermillerutils 1.00.00
*/
public void update (byte buffer[], int length) {
update(buffer, 0, length);
}
/**
* Update this hash with the given data.
*
* @param buffer Array of bytes to be hashed.
*
* @since ostermillerutils 1.00.00
*/
public void update (byte buffer[]) {
update(buffer, 0, buffer.length);
}
/**
* Updates this hash with a single byte.
*
* @param b byte to be hashed.
*
* @since ostermillerutils 1.00.00
*/
public void update (byte b) {
byte buffer[] = new byte[1];
buffer[0] = b;
update(buffer, 1);
}
/**
* Update this hash with a String.
* The string is converted to bytes using the current
* platform"s default character encoding.
*
* @param s String to be hashed.
*
* @since ostermillerutils 1.00.00
*/
public void update (String s) {
update(s.getBytes());
}
/**
* Update this hash with a String.
*
* @param s String to be hashed.
* @param enc The name of a supported character encoding.
* @throws UnsupportedEncodingException If the named encoding is not supported.
*
* @since ostermillerutils 1.00.00
*/
public void update (String s, String enc) throws UnsupportedEncodingException {
update(s.getBytes(enc));
}
/**
* The current state from which the hash sum
* can be computed or updated.
*
* @since ostermillerutils 1.00.00
*/
private MD5State workingState = new MD5State();
/**
* Cached copy of the final MD5 hash sum. This is created when
* the hash is requested and it is invalidated when the hash
* is updated.
*
* @since ostermillerutils 1.00.00
*/
private MD5State finalState = new MD5State();
/**
* Temporary buffer cached here for performance reasons.
*
* @since ostermillerutils 1.00.00
*/
private int[] decodeBuffer = new int[16];
/**
* 64 bytes of padding that can be added if the length
* is not divisible by 64.
*
* @since ostermillerutils 1.00.00
*/
private static final byte padding[] = {
(byte) 0x80, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
/**
* Contains internal state of the MD5 class.
* Passes MD5 test suite as defined in RFC1321.
*
* @since ostermillerutils 1.00.00
*/
private class MD5State {
/**
* True if this state is valid.
*
* @since ostermillerutils 1.00.00
*/
private boolean valid = true;
/**
* Reset to initial state.
*
* @since ostermillerutils 1.00.00
*/
private void reset(){
state[0] = 0x67452301;
state[1] = 0xefcdab89;
state[2] = 0x98badcfe;
state[3] = 0x10325476;
bitCount = 0;
}
/**
* 128-byte state
*
* @since ostermillerutils 1.00.00
*/
private int state[] = new int[4];
/**
* 64-bit count of the number of bits that have been hashed.
*
* @since ostermillerutils 1.00.00
*/
private long bitCount;
/**
* 64-byte buffer (512 bits) for storing to-be-hashed characters
*
* @since ostermillerutils 1.00.00
*/
private byte buffer[] = new byte[64];
private MD5State() {
reset();
}
/**
* Set this state to be exactly the same as some other.
*
* @param from state to copy from.
*
* @since ostermillerutils 1.00.00
*/
private void copy(MD5State from) {
System.arraycopy(from.buffer, 0, this.buffer, 0, this.buffer.length);
System.arraycopy(from.state, 0, this.state, 0, this.state.length);
this.valid = from.valid;
this.bitCount = from.bitCount;
}
}
/**
* Turns array of bytes into string representing each byte as
* a two digit unsigned hex number.
*
* @param hash Array of bytes to convert to hex-string
* @return Generated hex string
*
* @since ostermillerutils 1.00.00
*/
private static String toHex(byte hash[]){
StringBuffer buf = new StringBuffer(hash.length * 2);
for (byte element: hash) {
int intVal = element & 0xff;
if (intVal < 0x10){
// append a zero before a one digit hex
// number to make it two digits.
buf.append("0");
}
buf.append(Integer.toHexString(intVal));
}
return buf.toString();
}
private static int FF (int a, int b, int c, int d, int x, int s, int ac) {
a += ((b & c) | (~b & d));
a += x;
a += ac;
//return rotateLeft(a, s) + b;
a = (a << s) | (a >>> (32 - s));
return a + b;
}
private static int GG (int a, int b, int c, int d, int x, int s, int ac) {
a += ((b & d) | (c & ~d));
a += x;
a += ac;
//return rotateLeft(a, s) + b;
a = (a << s) | (a >>> (32 - s));
return a + b;
}
private static int HH (int a, int b, int c, int d, int x, int s, int ac) {
a += (b ^ c ^ d);
a += x;
a += ac;
//return rotateLeft(a, s) + b;
a = (a << s) | (a >>> (32 - s));
return a + b;
}
private static int II (int a, int b, int c, int d, int x, int s, int ac) {
a += (c ^ (b | ~d));
a += x;
a += ac;
//return rotateLeft(a, s) + b;
a = (a << s) | (a >>> (32 - s));
return a + b;
}
private static byte[] encode(long l){
byte[] out = new byte[8];
out[0] = (byte) (l & 0xff);
out[1] = (byte) ((l >>> 8) & 0xff);
out[2] = (byte) ((l >>> 16) & 0xff);
out[3] = (byte) ((l >>> 24) & 0xff);
out[4] = (byte) ((l >>> 32) & 0xff);
out[5] = (byte) ((l >>> 40) & 0xff);
out[6] = (byte) ((l >>> 48) & 0xff);
out[7] = (byte) ((l >>> 56) & 0xff);
return out;
}
private static byte[] encode(int input[], int len){
byte[] out = new byte[len];
int i, j;
for (i = j = 0; j < len; i++, j += 4) {
out[j] = (byte) (input[i] & 0xff);
out[j + 1] = (byte) ((input[i] >>> 8) & 0xff);
out[j + 2] = (byte) ((input[i] >>> 16) & 0xff);
out[j + 3] = (byte) ((input[i] >>> 24) & 0xff);
}
return out;
}
private int[] decode(byte buffer[], int len, int offset){
int i, j;
for (i = j = 0; j < len; i++, j += 4) {
decodeBuffer[i] = (
(buffer[j + offset] & 0xff)) |
(((buffer[j + 1 + offset] & 0xff)) << 8) |
(((buffer[j + 2 + offset] & 0xff)) << 16) |
(((buffer[j + 3 + offset] & 0xff)) << 24
);
}
return decodeBuffer;
}
private static void transform(MD5State state, int[] x){
int a = state.state[0];
int b = state.state[1];
int c = state.state[2];
int d = state.state[3];
/* Round 1 */
a = FF (a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
d = FF (d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
c = FF (c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
b = FF (b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
a = FF (a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
d = FF (d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
c = FF (c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
b = FF (b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
a = FF (a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
d = FF (d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
c = FF (c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
b = FF (b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
a = FF (a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
d = FF (d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
c = FF (c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
b = FF (b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
/* Round 2 */
a = GG (a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
d = GG (d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
c = GG (c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
b = GG (b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
a = GG (a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
d = GG (d, a, b, c, x[10], 9, 0x02441453); /* 22 */
c = GG (c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
b = GG (b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
a = GG (a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
d = GG (d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
c = GG (c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
b = GG (b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
a = GG (a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
d = GG (d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
c = GG (c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
b = GG (b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
/* Round 3 */
a = HH (a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
d = HH (d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
c = HH (c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
b = HH (b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
a = HH (a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
d = HH (d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
c = HH (c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
b = HH (b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
a = HH (a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
d = HH (d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
c = HH (c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
b = HH (b, c, d, a, x[ 6], 23, 0x04881d05); /* 44 */
a = HH (a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
d = HH (d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
c = HH (c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
b = HH (b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */
/* Round 4 */
a = II (a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
d = II (d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
c = II (c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
b = II (b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
a = II (a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
d = II (d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
c = II (c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
b = II (b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
a = II (a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
d = II (d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
c = II (c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
b = II (b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
a = II (a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
d = II (d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
c = II (c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
b = II (b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */
state.state[0] += a;
state.state[1] += b;
state.state[2] += c;
state.state[3] += d;
}
}
</source>
MD5 hashing: Encodes a string
<source lang="java">
/*
* Copyright (c) JForum Team * All rights reserved. * * Redistribution and use in source and binary forms, * with or without modification, are permitted provided * that the following conditions are met: * * 1) Redistributions of source code must retain the above * copyright notice, this list of conditions and the * following disclaimer. * 2) Redistributions in binary form must reproduce the * above copyright notice, this list of conditions and * the following disclaimer in the documentation and/or * other materials provided with the distribution. * 3) Neither the name of "Rafael Steil" nor * the names of its contributors may be used to endorse * or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER * IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE * * This file creation date: Mar 29, 2003 / 1:15:50 AM * The JForum Project * http://www.jforum.net */
import java.security.MessageDigest; import java.security.NoSuchAlgorithmException;
/**
* Encodes a string using MD5 hashing * * @author Rafael Steil * @version $Id: MD5.java,v 1.7 2006/08/23 02:13:44 rafaelsteil Exp $ */
public class MD5 {
/**
* Encodes a string
*
* @param str String to encode
* @return Encoded String
* @throws NoSuchAlgorithmException
*/
public static String crypt(String str)
{
if (str == null || str.length() == 0) {
throw new IllegalArgumentException("String to encript cannot be null or zero length");
}
StringBuffer hexString = new StringBuffer();
try {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(str.getBytes());
byte[] hash = md.digest();
for (int i = 0; i < hash.length; i++) {
if ((0xff & hash[i]) < 0x10) {
hexString.append("0" + Integer.toHexString((0xFF & hash[i])));
}
else {
hexString.append(Integer.toHexString(0xFF & hash[i]));
}
}
}
catch (NoSuchAlgorithmException e) {
throw new RuntimeException("" + e);
}
return hexString.toString();
}
}
</source>
MD5 String
<source lang="java">
/*
GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Contact info: lobochief@users.sourceforge.net
- /
import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; public class Strings {
private static final MessageDigest MESSAGE_DIGEST;
public static final String[] EMPTY_ARRAY = new String[0];
static {
MessageDigest md;
try {
md = MessageDigest.getInstance("MD5");
} catch(NoSuchAlgorithmException err) {
throw new IllegalStateException();
}
MESSAGE_DIGEST = md;
}
private static final String HEX_CHARS = "0123456789ABCDEF";
public static String getMD5(String source) {
byte[] bytes;
try {
bytes = source.getBytes("UTF-8");
} catch(java.io.UnsupportedEncodingException ue) {
throw new IllegalStateException(ue);
}
byte[] result;
synchronized(MESSAGE_DIGEST) {
MESSAGE_DIGEST.update(bytes);
result = MESSAGE_DIGEST.digest();
}
char[] resChars = new char[32];
int len = result.length;
for(int i = 0; i < len; i++) {
byte b = result[i];
int lo4 = b & 0x0F;
int hi4 = (b & 0xF0) >> 4;
resChars[i*2] = HEX_CHARS.charAt(hi4);
resChars[i*2 + 1] = HEX_CHARS.charAt(lo4);
}
return new String(resChars);
}
public static String getHash32(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 8);
}
public static String getHash64(String source) throws UnsupportedEncodingException {
String md5 = getMD5(source);
return md5.substring(0, 16);
}
}
</source>
Null Safe Hash Code
<source lang="java">
import java.lang.reflect.Array; import java.util.Arrays; /*
* Copyright 2002-2007 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
//Revised from springframework /**
* Miscellaneous object utility methods. Mainly for internal use within the * framework; consider Jakarta"s Commons Lang for a more comprehensive suite * of object utilities. * * @author Juergen Hoeller * @author Keith Donald * @author Rod Johnson * @author Rob Harrop * @author Alex Ruiz * @since 19.03.2004 * @see org.apache.rumons.lang.ObjectUtils */
abstract class ObjectUtils {
private static final int INITIAL_HASH = 7;
private static final int MULTIPLIER = 31;
private static final String EMPTY_STRING = "";
private static final String NULL_STRING = "null";
private static final String ARRAY_START = "{";
private static final String ARRAY_END = "}";
private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
private static final String ARRAY_ELEMENT_SEPARATOR = ", ";
/** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(boolean[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + hashCode(array[i]); } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(byte[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + array[i]; } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(char[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + array[i]; } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(double[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + hashCode(array[i]); } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(float[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + hashCode(array[i]); } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(int[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + array[i]; } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(long[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + hashCode(array[i]); } return hash; } /** * Return a hash code based on the contents of the specified array. * Ifarrayisnull, this method returns 0. */ public static int nullSafeHashCode(short[] array) { if (array == null) { return 0; } int hash = INITIAL_HASH; int arraySize = array.length; for (int i = 0; i < arraySize; i++) { hash = MULTIPLIER * hash + array[i]; } return hash; } /** * Return the same value as{@link Boolean#hashCode()}. * @see Boolean#hashCode() */ public static int hashCode(boolean bool) { return bool ? 1231 : 1237; } /** * Return the same value as{@link Double#hashCode()}. * @see Double#hashCode() */ public static int hashCode(double dbl) { long bits = Double.doubleToLongBits(dbl); return hashCode(bits); } /** * Return the same value as{@link Float#hashCode()}. * @see Float#hashCode() */ public static int hashCode(float flt) { return Float.floatToIntBits(flt); } /** * Return the same value as{@link Long#hashCode()}. * @see Long#hashCode() */ public static int hashCode(long lng) { return (int) (lng ^ (lng >>> 32)); }
}
</source>
Return as hash code for the given object
<source lang="java">
import java.lang.reflect.Array; import java.util.Arrays; /*
* Copyright 2002-2007 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
//Revised from springframework /**
* Miscellaneous object utility methods. Mainly for internal use within the * framework; consider Jakarta"s Commons Lang for a more comprehensive suite * of object utilities. * * @author Juergen Hoeller * @author Keith Donald * @author Rod Johnson * @author Rob Harrop * @author Alex Ruiz * @since 19.03.2004 * @see org.apache.rumons.lang.ObjectUtils */
abstract class ObjectUtils {
private static final int INITIAL_HASH = 7;
private static final int MULTIPLIER = 31;
private static final String EMPTY_STRING = "";
private static final String NULL_STRING = "null";
private static final String ARRAY_START = "{";
private static final String ARRAY_END = "}";
private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
private static final String ARRAY_ELEMENT_SEPARATOR = ", ";
/**
* Return as hash code for the given object; typically the value of
* {@link Object#hashCode()}. If the object is an array,
* this method will delegate to any of the nullSafeHashCode
* methods for arrays in this class. If the object is null,
* this method returns 0.
* @see #nullSafeHashCode(Object[])
* @see #nullSafeHashCode(boolean[])
* @see #nullSafeHashCode(byte[])
* @see #nullSafeHashCode(char[])
* @see #nullSafeHashCode(double[])
* @see #nullSafeHashCode(float[])
* @see #nullSafeHashCode(int[])
* @see #nullSafeHashCode(long[])
* @see #nullSafeHashCode(short[])
*/
public static int nullSafeHashCode(Object obj) {
if (obj == null) {
return 0;
}
if (obj instanceof Object[]) {
return nullSafeHashCode((Object[]) obj);
}
if (obj instanceof boolean[]) {
return nullSafeHashCode((boolean[]) obj);
}
if (obj instanceof byte[]) {
return nullSafeHashCode((byte[]) obj);
}
if (obj instanceof char[]) {
return nullSafeHashCode((char[]) obj);
}
if (obj instanceof double[]) {
return nullSafeHashCode((double[]) obj);
}
if (obj instanceof float[]) {
return nullSafeHashCode((float[]) obj);
}
if (obj instanceof int[]) {
return nullSafeHashCode((int[]) obj);
}
if (obj instanceof long[]) {
return nullSafeHashCode((long[]) obj);
}
if (obj instanceof short[]) {
return nullSafeHashCode((short[]) obj);
}
return obj.hashCode();
}
}
</source>
Secure Hash
<source lang="java">
/*
* JBoss DNA (http://www.jboss.org/dna) * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. Some portions may be licensed * to Red Hat, Inc. under one or more contributor license agreements. * See the AUTHORS.txt file in the distribution for a full listing of * individual contributors. * * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA * is licensed to you under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * JBoss DNA is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */
import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; /**
* @author Randall Hauch */
public class SecureHash {
/**
* Commonly-used hashing algorithms.
*/
public enum Algorithm {
MD2("MD2", "The MD2 message digest algorithm as defined in RFC 1319"),
MD5("MD5", "The MD5 message digest algorithm as defined in RFC 1321"),
SHA_1("SHA-1", "The Secure Hash Algorithm, as defined in Secure Hash Standard, NIST FIPS 180-1"),
SHA_256(
"SHA-256",
"New hash algorithms for which the draft Federal Information Processing Standard 180-2, "
+ "Secure Hash Standard (SHS) is now available. SHA-256 is a 256-bit hash function intended to provide 128 bits of "
+ "security against collision attacks."),
SHA_384(
"SHA-384",
"New hash algorithms for which the draft Federal Information Processing Standard 180-2, "
+ "Secure Hash Standard (SHS) is now available. A 384-bit hash may be obtained by truncating the SHA-512 output."),
SHA_512(
"SHA-512",
"New hash algorithms for which the draft Federal Information Processing Standard 180-2, "
+ "Secure Hash Standard (SHS) is now available. SHA-512 is a 512-bit hash function intended to provide 256 bits of security.");
private String name;
private String description;
private Algorithm( String name,
String description ) {
this.name = name;
this.description = description;
}
public String digestName() {
return this.name;
}
public String description() {
return this.description;
}
@Override
public String toString() {
return digestName();
}
}
/**
* Get the hash of the supplied content, using the supplied digest algorithm.
*
* @param algorithm the hashing function algorithm that should be used
* @param content the content to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
* @throws IllegalArgumentException if the algorithm is null
*/
public static byte[] getHash( Algorithm algorithm,
byte[] content ) throws NoSuchAlgorithmException {
return getHash(algorithm.digestName(), content);
}
/**
* Get the hash of the supplied content, using the supplied digest algorithm.
*
* @param algorithm the hashing function algorithm that should be used
* @param file the file containing the content to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
* @throws IllegalArgumentException if the algorithm is null
* @throws IOException if there is an error reading the file
*/
public static byte[] getHash( Algorithm algorithm,
File file ) throws NoSuchAlgorithmException, IOException {
return getHash(algorithm.digestName(), file);
}
/**
* Get the hash of the supplied content, using the supplied digest algorithm.
*
* @param algorithm the hashing function algorithm that should be used
* @param stream the stream containing the content to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
* @throws IllegalArgumentException if the algorithm is null
* @throws IOException if there is an error reading the stream
*/
public static byte[] getHash( Algorithm algorithm,
InputStream stream ) throws NoSuchAlgorithmException, IOException {
return getHash(algorithm.digestName(), stream);
}
/**
* Get the hash of the supplied content, using the digest identified by the supplied name.
*
* @param digestName the name of the hashing function (or {@link MessageDigest message digest}) that should be used
* @param content the content to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
*/
public static byte[] getHash( String digestName,
byte[] content ) throws NoSuchAlgorithmException {
MessageDigest digest = MessageDigest.getInstance(digestName);
assert digest != null;
return digest.digest(content);
}
/**
* Get the hash of the supplied content, using the digest identified by the supplied name.
*
* @param digestName the name of the hashing function (or {@link MessageDigest message digest}) that should be used
* @param file the file whose content is to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
* @throws IOException if there is an error reading the file
*/
public static byte[] getHash( String digestName,
File file ) throws NoSuchAlgorithmException, IOException {
MessageDigest digest = MessageDigest.getInstance(digestName);
assert digest != null;
InputStream in = new BufferedInputStream(new FileInputStream(file));
boolean error = false;
try {
int bufSize = 1024;
byte[] buffer = new byte[bufSize];
int n = in.read(buffer, 0, bufSize);
int count = 0;
while (n != -1) {
count += n;
digest.update(buffer, 0, n);
n = in.read(buffer, 0, bufSize);
}
} catch (IOException e) {
error = true;
throw e;
} finally {
try {
in.close();
} catch (IOException e) {
if (!error) throw e;
}
}
return digest.digest();
}
/**
* Get the hash of the supplied content, using the digest identified by the supplied name. Note that this method never closes
* the supplied stream.
*
* @param digestName the name of the hashing function (or {@link MessageDigest message digest}) that should be used
* @param stream the stream containing the content to be hashed; may not be null
* @return the hash of the contents as a byte array
* @throws NoSuchAlgorithmException if the supplied algorithm could not be found
* @throws IOException if there is an error reading the stream
*/
public static byte[] getHash( String digestName,
InputStream stream ) throws NoSuchAlgorithmException, IOException {
MessageDigest digest = MessageDigest.getInstance(digestName);
assert digest != null;
int bufSize = 1024;
byte[] buffer = new byte[bufSize];
int n = stream.read(buffer, 0, bufSize);
int count = 0;
while (n != -1) {
count += n;
digest.update(buffer, 0, n);
n = stream.read(buffer, 0, bufSize);
}
return digest.digest();
}
}
</source>
Unify Hash
<source lang="java">
/* UnifyHash Copyright (C) 1999-2002 Jochen Hoenicke.
* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program; see the file COPYING.LESSER. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id: UnifyHash.java.in,v 1.3.2.2 2002/05/28 17:34:24 hoenicke Exp $ */
///#ifdef JDK12 import java.lang.ref.WeakReference; import java.lang.ref.ReferenceQueue; ///#endif import java.util.ruparator; import java.util.AbstractCollection; import java.util.Iterator; import java.util.NoSuchElementException; import java.util.ConcurrentModificationException; import java.lang.UnsupportedOperationException; public class UnifyHash extends AbstractCollection {
/**
* the default capacity
*/
private static final int DEFAULT_CAPACITY = 11;
/** the default load factor of a HashMap */
private static final float DEFAULT_LOAD_FACTOR = 0.75F;
///#ifdef JDK12
private ReferenceQueue queue = new ReferenceQueue();
///#endif
static class Bucket
///#ifdef JDK12
extends WeakReference
///#endif
{
///#ifdef JDK12
public Bucket(Object o, ReferenceQueue q) {
super(o, q);
}
///#else /// public Bucket(Object o) { /// this.obj = o; /// } /// /// Object obj; /// /// public Object get() { /// return obj; /// } ///#endif
int hash;
Bucket next;
}
private Bucket[] buckets;
int modCount = 0;
int size = 0;
int threshold;
float loadFactor;
public UnifyHash(int initialCapacity, float loadFactor) {
this.loadFactor = loadFactor;
buckets = new Bucket[initialCapacity];
threshold = (int) (loadFactor * initialCapacity);
}
public UnifyHash(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
public UnifyHash() {
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
}
private void grow() {
Bucket[] oldBuckets = buckets;
int newCap = buckets.length * 2 + 1;
threshold = (int) (loadFactor * newCap);
buckets = new Bucket[newCap];
for (int i = 0; i < oldBuckets.length; i++) {
Bucket nextBucket;
for (Bucket b = oldBuckets[i]; b != null; b = nextBucket) {
if (i != Math.abs(b.hash % oldBuckets.length))
throw new RuntimeException(""+i+", hash: "+b.hash+", oldlength: "+oldBuckets.length);
int newSlot = Math.abs(b.hash % newCap);
nextBucket = b.next;
b.next = buckets[newSlot];
buckets[newSlot] = b;
}
}
}
///#ifdef JDK12
public final void cleanUp() {
Bucket died;
while ((died = (Bucket)queue.poll()) != null) {
int diedSlot = Math.abs(died.hash % buckets.length);
if (buckets[diedSlot] == died)
buckets[diedSlot] = died.next;
else {
Bucket b = buckets[diedSlot];
while (b.next != died)
b = b.next;
b.next = died.next;
}
size--;
}
}
///#endif
public int size() {
return size;
}
public Iterator iterator() {
///#ifdef JDK12
cleanUp();
///#endif
return new Iterator() {
private int bucket = 0;
private int known = modCount;
private Bucket nextBucket;
private Object nextVal;
{
internalNext();
}
private void internalNext() {
while (true) {
while (nextBucket == null) {
if (bucket == buckets.length)
return;
nextBucket = buckets[bucket++];
}
nextVal = nextBucket.get();
if (nextVal != null)
return;
nextBucket = nextBucket.next;
}
}
public boolean hasNext() {
return nextBucket != null;
}
public Object next() {
if (known != modCount)
throw new ConcurrentModificationException();
if (nextBucket == null)
throw new NoSuchElementException();
Object result = nextVal;
nextBucket = nextBucket.next;
internalNext();
return result;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
public Iterator iterateHashCode(final int hash) {
///#ifdef JDK12
cleanUp();
///#endif
return new Iterator() {
private int known = modCount;
private Bucket nextBucket
= buckets[Math.abs(hash % buckets.length)];
private Object nextVal;
{
internalNext();
}
private void internalNext() {
while (nextBucket != null) {
if (nextBucket.hash == hash) {
nextVal = nextBucket.get();
if (nextVal != null)
return;
}
nextBucket = nextBucket.next;
}
}
public boolean hasNext() {
return nextBucket != null;
}
public Object next() {
if (known != modCount)
throw new ConcurrentModificationException();
if (nextBucket == null)
throw new NoSuchElementException();
Object result = nextVal;
nextBucket = nextBucket.next;
internalNext();
return result;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
public void put(int hash, Object o) {
if (size++ > threshold)
grow();
modCount++;
int slot = Math.abs(hash % buckets.length);
///#ifdef JDK12
Bucket b = new Bucket(o, queue);
///#else /// Bucket b = new Bucket(o); ///#endif
b.hash = hash;
b.next = buckets[slot];
buckets[slot] = b;
}
public Object unify(Object o, int hash, Comparator comparator) {
///#ifdef JDK12
cleanUp();
///#endif
int slot = Math.abs(hash % buckets.length);
for (Bucket b = buckets[slot]; b != null; b = b.next) {
Object old = b.get();
if (old != null && comparator.rupare(o, old) == 0)
return old;
}
put(hash, o);
return o;
}
}
</source>
