package util;
/*
 * @(#)ExampleFileFilter.java	1.9 99/04/23
 *
 * Copyright (c) 1998, 1999 by Sun Microsystems, Inc. All Rights Reserved.
 *
 */


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.
 *
 * Example - create a new filter that filerts out all files
 * but gif and jpg image files:
 *
 *     JFileChooser chooser = new JFileChooser();
 *     StandardFileFilter filter = new StandardFileFilter(
 *                   new String{"gif", "jpg"}, "JPEG & GIF Images")
 *     chooser.addChoosableFileFilter(filter);
 *     chooser.showOpenDialog(this);
 *
 * @version 1.9 04/23/99
 * @author Jeff Dinkins
 */
public class StandardFileFilter extends FileFilter {

	private static String TYPE_UNKNOWN = "Type Unknown";
	private static String HIDDEN_FILE = "Hidden File";

	private Hashtable 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 StandardFileFilter() {
	this.filters = new Hashtable();
	}

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

	/**
	 * Creates a file filter that accepts the given file type.
	 * Example: new StandardFileFilter("jpg", "JPEG Image Images");
	 *
	 * Note that the "." before the extension is not needed. If
	 * provided, it will be ignored.
	 *
	 * @see #addExtension
	 */
	public StandardFileFilter(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 StandardFileFilter(String {"gif", "jpg"});
	 *
	 * Note that the "." before the extension is not needed adn
	 * will be ignored.
	 *
	 * @see #addExtension
	 */
	public StandardFileFilter(String[] filters) {
	this(filters, null);
	}

	/**
	 * Creates a file filter from the given string array and description.
	 * Example: new StandardFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
	 *
	 * Note that the "." before the extension is not needed and will be ignored.
	 *
	 * @see #addExtension
	 */
	public StandardFileFilter(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.
	 *
	 * @see #getExtension
	 * @see FileFilter#accepts
	 */
	public boolean accept(File f) {
	if(f != null) {
	    if(f.isDirectory()) {
		return true;
	    }
	    String extension = getExtension(f);
	    if(extension != null && filters.get(getExtension(f)) != 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":
	 *
	 *   StandardFileFilter filter = new StandardFileFilter();
	 *   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(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)"
	 *
	 * @see setDescription
	 * @see setExtensionListInDescription
	 * @see isExtensionListInDescription
	 * @see FileFilter#getDescription
	 */
	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");
	 *
	 * @see setDescription
	 * @see setExtensionListInDescription
	 * @see isExtensionListInDescription
	 */
	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();
	 *
	 * @see getDescription
	 * @see setDescription
	 * @see isExtensionListInDescription
	 */
	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();
	 *
	 * @see getDescription
	 * @see setDescription
	 * @see setExtensionListInDescription
	 */
	public boolean isExtensionListInDescription() {
	return useExtensionsInDescription;
	}
}