Java Tutorial/File/FilenameFilter
Содержание
A filesystem filter.
/*
* JCommon : a free general purpose class library for the Java(tm) platform
*
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------------------
* ExtensionFileFilter.java
* ------------------------
* (C) Copyright 2000-2004, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* $Id: FilesystemFilter.java,v 1.6 2008/09/10 09:26:11 mungady Exp $
*
* Changes (from 26-Oct-2001)
* --------------------------
* 01-Jun-2005 : Updated javadoc.
*/
import java.io.File;
import java.io.FilenameFilter;
import javax.swing.filechooser.FileFilter;
/**
* A filesystem filter.
*
* @author David Gilbert
*/
public class FilesystemFilter extends FileFilter implements FilenameFilter {
/** The file extension, which should be accepted. */
private String[] fileext;
/** The filter description. */
private String descr;
/** A flag indicating whether to accept directories. */
private boolean accDirs;
/**
* Creates a new filter.
*
* @param fileext
* the file extension.
* @param descr
* the description.
*/
public FilesystemFilter(final String fileext, final String descr) {
this(fileext, descr, true);
}
/**
* Creates a new filter.
*
* @param fileext
* the file extension.
* @param descr
* the description.
* @param accDirs
* accept directories?
*/
public FilesystemFilter(final String fileext, final String descr, final boolean accDirs) {
this(new String[] { fileext }, descr, accDirs);
}
/**
* Creates a new filter.
*
* @param fileext
* the file extension.
* @param descr
* the description.
* @param accDirs
* accept directories?
* @throws NullPointerException
* if the file extensions are null.
*/
public FilesystemFilter(final String[] fileext, final String descr, final boolean accDirs) {
this.fileext = (String[]) fileext.clone();
this.descr = descr;
this.accDirs = accDirs;
}
/**
* Returns <code>true</code> if the file is accepted, and <code>false</code>
* otherwise.
*
* @param dir
* the directory.
* @param name
* the file name.
* @return A boolean.
*/
public boolean accept(final File dir, final String name) {
final File f = new File(dir, name);
if (f.isDirectory() && acceptsDirectories()) {
return true;
}
for (int i = 0; i < this.fileext.length; i++) {
if (name.endsWith(this.fileext[i])) {
return true;
}
}
return false;
}
/**
* Returns <code>true</code> if the specified file matches the requirements
* of this filter, and <code>false</code> otherwise.
*
* @param dir
* the file or directory.
* @return A boolean.
*/
public boolean accept(final File dir) {
if (dir.isDirectory() && acceptsDirectories()) {
return true;
}
for (int i = 0; i < this.fileext.length; i++) {
if (dir.getName().endsWith(this.fileext[i])) {
return true;
}
}
return false;
}
/**
* Returns the filter description.
*
* @return The filter description.
*/
public String getDescription() {
return this.descr;
}
/**
* Sets the flag that controls whether or not the filter accepts directories.
*
* @param b
* a boolean.
*/
public void acceptDirectories(final boolean b) {
this.accDirs = b;
}
/**
* Returns the flag that indicates whether or not the filter accepts
* directories.
*
* @return A boolean.
*/
public boolean acceptsDirectories() {
return this.accDirs;
}
}
A prefix based filename filter
/*
* 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.File;
import java.io.FilenameFilter;
/**
* A <em>prefix</em> based filename filter.
*
* @version <tt>$Revision: 1958 $</tt>
* @author
*/
public class FilenamePrefixFilter
implements FilenameFilter
{
/** The prefix which files must have to be accepted. */
protected final String prefix;
/** Flag to signal that we want to ignore the case. */
protected final boolean ignoreCase;
/**
* Construct a <tt>FilenamePrefixFilter</tt>.
*
* @param prefix The prefix which files must have to be accepted.
* @param ignoreCase <tt>True</tt> if the filter should be case-insensitive.
*/
public FilenamePrefixFilter(final String prefix,
final boolean ignoreCase)
{
this.ignoreCase = ignoreCase;
this.prefix = (ignoreCase ? prefix.toLowerCase() : prefix);
}
/**
* Construct a case sensitive <tt>FilenamePrefixFilter</tt>.
*
* @param prefix The prefix which files must have to be accepted.
*/
public FilenamePrefixFilter(final String prefix) {
this(prefix, false);
}
/**
* Check if a file is acceptible.
*
* @param dir The directory the file resides in.
* @param name The name of the file.
* @return <tt>true</tt> if the file is acceptable.
*/
public boolean accept(final File dir, final String name) {
if (ignoreCase) {
return name.toLowerCase().startsWith(prefix);
}
else {
return name.startsWith(prefix);
}
}
}
Combine FilenameFilter and Pattern match to create a dir command
import java.io.File;
import java.io.FilenameFilter;
import java.util.Arrays;
import java.util.regex.Pattern;
public class MainClass {
public static void main(final String[] args) {
File path = new File(".");
String[] list;
if (args.length == 0)
list = path.list();
else
list = path.list(new FilenameFilter() {
private Pattern pattern = Pattern.rupile(args[0]);
public boolean accept(File dir, String name) {
return pattern.matcher(new File(name).getName()).matches();
}
});
Arrays.sort(list);
for (int i = 0; i < list.length; i++)
System.out.println(list[i]);
}
}
File filter: retrieve at most predefined number of files which are older than specified data
/*
* Copyright (c) 2003 - 2007 OpenSubsystems s.r.o. Slovak Republic. All rights reserved.
*
* Project: OpenSubsystems
*
* $Id: MaximumFileFilter.java,v 1.4 2007/01/07 06:14:00 bastafidli Exp $
*
* 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; version 2 of the License.
*
* 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 General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.io.File;
import java.io.FilenameFilter;
import java.util.Date;
/**
* File filter implementation to retrieve at most predefined number of files
* which are older than specified data
*
* @version $Id: MaximumFileFilter.java,v 1.4 2007/01/07 06:14:00 bastafidli Exp $
* @author Miro Halas
* @code.reviewer Miro Halas
* @code.reviewed 1.2 2004/12/18 06:18:25 bastafidli
*/
public class MaximumFileFilter implements FilenameFilter
{
// Attributes ///////////////////////////////////////////////////////////////
/**
* Current number of files in list
*/
protected int m_currentFileCount = 0;
/**
* Maximum number of files in output list
*/
protected int m_iMaximum = 0;
/**
* Last modification time of file have to be before this date, if it is null,
* modification date is not checked
*/
protected Date m_dtOlderThan;
// Constructors /////////////////////////////////////////////////////////////
/**
* Constructor with maximum count of file in the output list.
*
* @param iMax - maximum number of files in output list. If it is 0 length of
* @param dtOlderThen - file last modification time heve to by before this
* date, if it is null modification time is not checked
* output list is unlimited.
*/
public MaximumFileFilter(
int iMax,
Date dtOlderThen
)
{
m_iMaximum = iMax;
m_dtOlderThan = dtOlderThen;
}
/**
* {@inheritDoc}
*/
public boolean accept(
File dir,
String name
)
{
File currentFile = new File(dir, name);
if (currentFile.isDirectory())
{
return false;
}
if ((m_dtOlderThan != null) && (currentFile.lastModified() > m_dtOlderThan.getTime()))
{
return false;
}
if ((m_iMaximum == 0) || (m_currentFileCount <= m_iMaximum))
{
m_currentFileCount++;
}
return m_currentFileCount <= m_iMaximum;
}
}
Filter files by name
import java.io.File;
import java.io.FileFilter;
import java.io.FilenameFilter;
public class Main {
public static void main(String[] argv) throws Exception {
File dir = new File("c:\\temp");
FilenameFilter filter = new FilenameFilter() {
public boolean accept(File dir, String name) {
return !name.startsWith(".");
}
};
String[] children = dir.list(filter);
}
}
strip Extension name
import java.io.File;
public class Main {
/**
* org/my/Class.xxx -> org/my/Class
*/
public static String stripExtension( final String pResourceName ) {
final int i = pResourceName.lastIndexOf(".");
if (i < 0) {
return pResourceName;
}
final String withoutExtension = pResourceName.substring(0, i);
return withoutExtension;
}
}
