/*
 * @(#)ExtensionFileFilter.java        1.7 99/04/23
 *
 * Copyright (c) 1998, 1999 by Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * 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 AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE 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 SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */
package diva.gui;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

import javax.swing.filechooser.FileFilter;

/**
 * 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 Macintosh. Case is ignored.
 *
 * Extension - create a new filter that filters out all files
 * but gif and jpg image files:
 *
 *     JFileChooser chooser = new JFileChooser();
 *     ExtensionFileFilter filter = new ExtensionFileFilter(
 *                   new String{"gif", "jpg"}, "JPEG & GIF Images")
 *     chooser.addChoosableFileFilter(filter);
 *     chooser.showOpenDialog(this);
 *
 * @version 1.7 04/23/99
 * @author Jeff Dinkins
 */
public class ExtensionFileFilter 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(String)
     */
    public ExtensionFileFilter() {
        this((String) null, (String) null);
    }

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

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

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

    /**
     * Creates a file filter from the given string array and description.
     * Example: new ExtensionFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
     *
     * Note that the "." before the extension is not needed and will be
     * ignored.
     *
     * @see #addExtension(String)
     */
    public ExtensionFileFilter(String[] filters, String description) {
        this.filters = new Hashtable(filters.length);

        for (int i = 0; i < filters.length; i++) {
            // add filters one by one
            addExtension(filters[i]);
        }

        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(File)
     * @see FileFilter#accept(File)
     */
    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;
    }

    /**
     * If the filter contains only one extension, return the extension
     * name.  Otherwise, return null.
     *
     * Added by Heloise Hse
     */
    public String getDefaultExtension() {
        if (filters.size() == 1) {
            return (String) filters.keys().nextElement();
        } else {
            return null;
        }
    }

    /**
     * Return the extension portion of the file's name .
     */
    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":
     *
     *   ExtensionFileFilter filter = new ExtensionFileFilter();
     *   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(String)
     * @see #setExtensionListInDescription(boolean)
     * @see #isExtensionListInDescription()
     * @see FileFilter#getDescription()
     */
    public String getDescription() {
        if (fullDescription == null) {
            if ((description == null) || isExtensionListInDescription()) {
                if (description != null) {
                    fullDescription = description;
                }

                fullDescription += " (";

                // 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(String)
     * @see #setExtensionListInDescription(boolean)
     * @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 relevant if a description was provided in the constructor
     * or using setDescription();
     *
     * @see #getDescription()
     * @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 relevant if a description was provided in the constructor
     * or using setDescription();
     *
     * @see #getDescription()
     */
    public boolean isExtensionListInDescription() {
        return useExtensionsInDescription;
    }

    /**
     * Return a string description of this filter.
     *
     * @see #getDescription()
     */
    public String toString() {
        return getDescription();
    }
}