package org.astrogrid.ui;
   
   // A copy of the example FileFilter implementation that is provided as an
   // example in the SDK demos, but not in the library - MCH
   
   /*
    * @(#)ExampleFileFilter.java 1.9 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.
   */
  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 1.9 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
     */
     public ExtensionFileFilter() {
       this.filters = new Hashtable();
     }
     /***
     * 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 ExtensionFileFilter(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 ExtensionFileFilter(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);
    }
    /***
    * Creates a file filter that accepts files with the given extension.
    * Example: new ExampleFileFilter("jpg");
    *
    * @see #addExtension
    */
    public ExtensionFileFilter(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 ExtensionFileFilter(String extension, String description) {
      this();
      if(extension!=null) addExtension(extension);
      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;
    }
    /***
    * 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(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;
    }
    /***
    * 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;
    }
    /***
    * 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;
    }
    /***
    * 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;
    }
 }