playlistviewer.java

Eclipse高级编程3源码(书本源码)

/*******************************************************************************
 * Copyright (c) 2004 Berthold Daum. All rights reserved. This program and the
 * accompanying materials are made available under the terms of the Common
 * Public License v1.0 which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors: Berthold Daum
 ******************************************************************************/
package com.bdaum.jukebox;

import java.io.File;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.viewers.*;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.*;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.FileTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.*;

/**
 * This class implements a viewer for playlists.
 */
public class PlaylistViewer extends TableViewer {

  // File extension for for playlists
  public final static String PLS = ".jpl";
  // Filter for the selection of playlist files
  public final static String[] PLAYLISTEXTENSIONS = new String[]{"*"
                  + PLS};
  // Filter for the selection of sound files
  public final static String[] SOUNDEXTENSIONS = new String[]{
                  "*.m3u;*.wsz;*.mpg;*.snd;*.aifc;*.aif;*.wav;*.au;*.mp1;*.mp2;*.mp3;*.ogg",
                  "*.*"};
  // Filter for the selection of image files
  public final static String[] IMAGEEXTENSIONS = new String[]{
                  "*.gif; *.jpg; *.jpeg; *.png; *.bmp; *.tif",
                  "*.*"};

  // the playlist model instance
  private IPlaylist playlistModel;
  // the label provider for the table
  private ITableLabelProvider labelProvider;

  // Widgets
  private MenuItem newPlaylistItem, openPlaylistItem;
  private Label statusLine;
  private ToolItem insertButton, deleteButton, upButton,
                  downButton;

  private ICellModifier cellModifier = new ICellModifier() {
    // Get value from model
    public Object getValue(Object element, String property) {
      return playlistModel.getFeature(element, property);
    }

    // All elements may be modified by the end user
    public boolean canModify(Object element, String property) {
      return true;
    }

    // Set value in the model
    public void modify(Object element, String property,
                    Object value) {
      // ATTENTION: A TableItem instance may be passed as
      // element
      // In this case we retrieve the playlist entry from
      // the TableItem
      if (element instanceof Item)
        element = ((Item) element).getData();
      // To be safe we validate the new value
      if (validateFeature(property, (String) value) == null) {
        // OK, we set the new value in the model
        playlistModel.setFeature(element, property,
                        (String) value);
        // Refresh the viewer so that the new value is
        // shown in the table
        PlaylistViewer.this.refresh();
      }
    }
  };

  /**
   * Validates a feature
   * 
   * @param tag -
   *        Feature name
   * @param value -
   *        Value
   * @return String