Java Tutorial/File/FilenameFilter
Содержание
A filesystem filter.
<source lang="java">
/*
* 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 true if the file is accepted, and false
* 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 true if the specified file matches the requirements
* of this filter, and false 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;
}
}</source>
A prefix based filename filter
<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.File; import java.io.FilenameFilter; /**
* A prefix based filename filter. * * @version $Revision: 1958 $ * @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 FilenamePrefixFilter.
*
* @param prefix The prefix which files must have to be accepted.
* @param ignoreCase True 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 FilenamePrefixFilter.
*
* @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 true 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);
}
}
}</source>
Combine FilenameFilter and Pattern match to create a dir command
<source lang="java">
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]);
}
}</source>
File filter: retrieve at most predefined number of files which are older than specified data
<source lang="java">
/*
* 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;
}
}</source>
Filter files by name
<source lang="java">
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);
}
}</source>
strip Extension name
<source lang="java">
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;
}
}</source>
