defaultfilefilter.java

实现了一个由时间服务器

package client.tools;

/*
 * @(#)ExampleFileFilter.java 1.16 04/07/26 Copyright (c) 2004 Sun Microsystems,
 * Inc. All Rights Reserved. Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided that the following
 * conditions are met: -Redistribution of source code must retain the above
 * copyright notice, this list of conditions and the following disclaimer.
 * -Redistribution 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. Neither the name of
 * Sun Microsystems, Inc. or the names of contributors may be used to endorse or
 * promote products derived from this software without specific prior written
 * permission. This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC.
 * ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. You
 * acknowledge that this software is not designed, licensed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 */

/*
 * @(#)ExampleFileFilter.java 1.16 04/07/26
 */

import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.filechooser.*;

/**
 * A convenience implementation of FileFilter that filters out all files except
 * for those type extensions that it knows about. Extensions are of the type
 * ".foo", which is typically found on Windows and Unix boxes, but not on
 * Macinthosh. Case is ignored. Example - create a new filter that filerts out
 * all files but gif and jpg image files: JFileChooser chooser = new
 * JFileChooser(); ExampleFileFilter filter = new ExampleFileFilter( new
 * String[]{"gif", "jpg"}, "JPEG & GIF Images")
 * chooser.addChoosableFileFilter(filter); chooser.showOpenDialog(this);
 * 
 * @version 1.16 07/26/04
 * @author Jeff Dinkins
 */
public class DefaultFileFilter extends FileFilter
{
    private Hashtable<String, FileFilter> filters = null;

    private String description = null;

    private String fullDescription = null;

    private boolean useExtensionsInDescription = true;

    /**
         * Creates a file filter. If no filters are added, then all files are
         * accepted.
         * 
         * @see #addExtension
         */
    public DefaultFileFilter()
    {
	this.filters = new Hashtable<String, FileFilter>();
    }

    /**
         * Creates a file filter that accepts files with the given extension.
         * Example: new ExampleFileFilter("jpg");
         * 
         * @see #addExtension
         */
    public DefaultFileFilter(String extension)
    {
	this(extension, null);
    }

    /**
         * Creates a file filter that accepts the given file type. Example: new
         * ExampleFileFilter("jpg", "JPEG Image Images"); Note that the "."
         * before the extension is not needed. If provided, it will be ignored.
         * 
         * @see #addExtension
         */
    public DefaultFileFilter(String extension, String description)
    {
	this();
	if (extension != null)
	    addExtension(extension);
	if (description != null)
	    setDescription(description);
    }

    /**
         * Creates a file filter from the given string array. Example: new
         * ExampleFileFilter(String {"gif", "jpg"}); Note that the "." before
         * the extension is not needed adn will be ignored.
         * 
         * @see #addExtension
         */
    public DefaultFileFilter(String[] filters)
    {
	this(filters, null);
    }

    /**
         * Creates a file filter from the given string array and description.
         * Example: new ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG
         * Images"); Note that the "." before the extension is not needed and
         * will be ignored.
         * 
         * @see #addExtension
         */
    public DefaultFileFilter(String[] filters, String description)
    {
	this();
	for (int i = 0; i < filters.length; i++)
	{
	    // add filters one by one
	    addExtension(filters[i]);
	}
	if (description != null)
	    setDescription(description);
    }

    /**
         * Return true if this file should be shown in the directory pane, false
         * if it shouldn't. Files that begin with "." are ignored.
         */
    public boolean accept(File f)
    {
	if (f != null)
	{

	    if (f.isDirectory())
	    {
		return true;
	    }
	    String extension = getExtension(f);
	    if (extension != null && filters.get(extension) != null)
	    {
		return true;
	    }
	}
	return false;
    }

    /**
         * Return the extension portion of the file's name .
         * 
         * @see #getExtension
         * @see FileFilter#accept
         */
    public String getExtension(File f)
    {
	if (f != null)
	{
	    String filename = f.getName();
	    int i = filename.lastIndexOf('.');
	    if (i > 0 && i < filename.length() - 1)
	    {
		return filename.substring(i + 1).toLowerCase();
	    }
	}
	return null;
    }

    /**
         * Adds a filetype "dot" extension to filter against. For example: the
         * following code will create a filter that filters out all files except
         * those that end in ".jpg" and ".tif": ExampleFileFilter filter = new
         * ExampleFileFilter(); filter.addExtension("jpg");
         * filter.addExtension("tif"); Note that the "." before the extension is
         * not needed and will be ignored.
         */
    public void addExtension(String extension)
    {
	if (filters == null)
	{
	    filters = new Hashtable<String, FileFilter>(5);
	}
	filters.put(extension.toLowerCase(), this);
	fullDescription = null;
    }

    /**
         * Returns the human readable description of this filter. For example:
         * "JPEG and GIF Image Files (*.jpg, *.gif)"
         */
    public String getDescription()
    {
	if (fullDescription == null)
	{
	    if (description == null || isExtensionListInDescription())
	    {
		fullDescription = description == null ? "(" : description
			+ " (";
		// build the description from the extension list
		Enumeration extensions = filters.keys();
		if (extensions != null)
		{
		    fullDescription += "." + (String) extensions.nextElement();
		    while (extensions.hasMoreElements())
		    {
			fullDescription += ", ."
				+ (String) extensions.nextElement();
		    }
		}
		fullDescription += ")";
	    }
	    else
	    {
		fullDescription = description;
	    }
	}
	return fullDescription;
    }

    /**
         * Sets the human readable description of this filter. For example:
         * filter.setDescription("Gif and JPG Images");
         */
    public void setDescription(String description)
    {
	this.description = description;
	fullDescription = null;
    }

    /**
         * Determines whether the extension list (.jpg, .gif, etc) should show
         * up in the human readable description. Only relevent if a description
         * was provided in the constructor or using setDescription();
         */
    public void setExtensionListInDescription(boolean b)
    {
	useExtensionsInDescription = b;
	fullDescription = null;
    }

    /**
         * Returns whether the extension list (.jpg, .gif, etc) should show up
         * in the human readable description. Only relevent if a description was
         * provided in the constructor or using setDescription();
         */
    public boolean isExtensionListInDescription()
    {
	return useExtensionsInDescription;
    }
}