в 17:43, 31 мая 2010

2010-05-31T17:43:48Z

Admin: 1 версия

2010-05-31T14:39:32Z

1 версия

Новая страница

== Array: clone() ==



<source lang="java">

/*
Output:
Original size: 5
New size: 5
Original size: 9
New size: 9

* */
public class MainClass {
public static void main (String args[]) {
int array1[] = {1, 2, 3, 4, 5};
int array2[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
System.out.println("Original size: " + array1.length);
System.out.println("New size: " + cloneArray(array1).length);
System.out.println("Original size: " + array2.length);
System.out.println("New size: " + cloneArray(array2).length);
}
static int[] cloneArray(int original[]) {
return (int[])original.clone();
}
}

</source>



== Array: getInt(Object array, int index) ==



<source lang="java">

/*
Output:
Position: 0, value: 1040988893
Position: 1, value: -2073064706
Position: 2, value: -808861084
* */
import java.lang.reflect.Array;
import java.util.Random;
public class MainClass {
public static void main (String args[]) {
Object array = Array.newInstance(int.class, 3);

int length = Array.getLength(array);
Random generator = new Random(System.currentTimeMillis());
for (int i=0; i<length; i++) {
int random = generator.nextInt();
Array.setInt(array, i, random);
}

for (int i=0; i<length; i++) {
int value = Array.getInt(array, i);
System.out.println("Position: " + i + ", value: " + value);
}
}
}

</source>



== Array: getLength(Object array) ==



<source lang="java">

/*
Output:
Array of: int
Array size: 3
* */
import java.lang.reflect.Array;
public class MainClass {
public static void main (String args[]) {
Object array = Array.newInstance(int.class, 3);

Class type = array.getClass();
if (type.isArray()) {
Class elementType = type.getComponentType();
System.out.println("Array of: " + elementType);
System.out.println("Array size: " + Array.getLength(array));
}

}
}

</source>



== Array: get(Object array, int index) ==



<source lang="java">

import java.lang.reflect.Array;
public class Main {
public static Object copyArray(final Object input) {
final Class type = input.getClass();
if (!type.isArray()) {
throw new IllegalArgumentException();
}
final int length = Array.getLength(input);
final Class componentType = type.getComponentType();
final Object result = Array.newInstance(componentType, length);
for (int idx = 0; idx < length; idx++) {
Array.set(result, idx, Array.get(input, idx));
}
return result;
}
public static void main(final String[] args) {
try {
int[] x = new int[] { 2, 3, 8, 7, 5 };
char[] y = new char[] { "a", "z", "e" };
String[] z = new String[] { "Jim", "John", "Joe" };
System.out.println(" -- z and copy of z --");
outputArrays(z, copyArray(z));
} catch (final Exception ex) {
ex.printStackTrace();
}
}

public static void outputArrays(final Object first, final Object second) {
if (!first.getClass().isArray()) {
throw new IllegalArgumentException("first is not an array.");
}
if (!second.getClass().isArray()) {
throw new IllegalArgumentException("second is not an array.");
}
final int lengthFirst = Array.getLength(first);
final int lengthSecond = Array.getLength(second);
final int length = Math.max(lengthFirst, lengthSecond);
for (int idx = 0; idx < length; idx++) {
System.out.print("[" + idx + "]\t");
if (idx < lengthFirst) {
System.out.print(Array.get(first, idx) + "\t\t");
} else {
System.out.print("\t\t");
}
if (idx < lengthSecond) {
System.out.print(Array.get(second, idx) + "\t");
}
System.out.println();
}
}
}

</source>



== Array: newInstance(Class<?> componentType, int... dimensions) ==



<source lang="java">

import java.lang.reflect.Array;
public class Main {
public static void main(String[] argv) throws Exception {
int[][] ints2 = (int[][]) Array.newInstance(int.class, new int[] { 10, 20 });
}
}

</source>



== Array: newInstance(Class componentType, int length) ==



<source lang="java">

/*
Output:
Array of: int
Array size: 3
* */
import java.lang.reflect.Array;
public class MainClass {
public static void main (String args[]) {
Object array = Array.newInstance(int.class, 3);

Class type = array.getClass();
if (type.isArray()) {
Class elementType = type.getComponentType();
System.out.println("Array of: " + elementType);
System.out.println("Array size: " + Array.getLength(array));
}

}
}

</source>



== Array: setInt(Object array, int index, int i) ==



<source lang="java">

/*
Output:
Position: 0, value: 1040988893
Position: 1, value: -2073064706
Position: 2, value: -808861084
* */
import java.lang.reflect.Array;
import java.util.Random;
public class MainClass {
public static void main (String args[]) {
Object array = Array.newInstance(int.class, 3);

int length = Array.getLength(array);
Random generator = new Random(System.currentTimeMillis());
for (int i=0; i<length; i++) {
int random = generator.nextInt();
Array.setInt(array, i, random);
}

for (int i=0; i<length; i++) {
int value = Array.getInt(array, i);
System.out.println("Position: " + i + ", value: " + value);
}
}
}

</source>



== Array: setLong(Object array, int index, long l) ==



<source lang="java">

import java.lang.reflect.Array;
public class Main {
public static void main(String... args) {
Object o = new int[2];
Array.setShort(o, 0, (short) 2); // widening, succeeds
Array.setLong(o, 1, 2L); // narrowing, fails
}
}

</source>



== Array: set(Object array, int index, Object value) ==



<source lang="java">

import java.lang.reflect.Array;
public class Main {
public static void main(String[] argv) throws Exception {
int[] array = { 1, 2, 3 };
// Get the value of the third element.
Object o = Array.get(array, 2);
// Set the value of the third element.
Array.set(array, 2, 1);
}
}

</source>



== Array: setShort(Object array, int index, short s) ==



<source lang="java">

import java.lang.reflect.Array;
public class Main {
public static void main(String... args) {
Object o = new int[2];
Array.setShort(o, 0, (short) 2); // widening, succeeds
Array.setLong(o, 1, 2L); // narrowing, fails
}
}

</source>

← Предыдущая	Версия 17:43, 31 мая 2010
(нет различий)

Java by API/java.lang.reflect/Array - История изменений

в 17:43, 31 мая 2010

Admin: 1 версия