/*
 * Licensed Materials - Property of IBM
 * IBM SDK/J2RE 1.2
 * Copyright IBM Corp. 1999  All Rights Reserved
 * Copyright (c) 1998, 1999 by Sun Microsystems, Inc. All Rights Reserved.
 */

package ca.bc.webarts.widgets;

import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.*;
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 ExampleFileFilter 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 ExampleFileFilter() {
  this.filters = new Hashtable();
    }

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

    /**
     * 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;
    }
}