001/* PopupFactory.java --
002   Copyright (C) 2003 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing;
040
041import java.awt.Component;
042import java.awt.Dimension;
043import java.awt.Point;
044
045
046/**
047 * A factory for <code>Popup</code> objects. These are used to
048 * managed little windows that float over everything else,
049 * typically containing a popup menu.
050 *
051 * @since 1.4
052 *
053 * @author Sascha Brawer (brawer@dandelis.ch)
054 */
055public class PopupFactory
056{
057  /**
058   * The shared factory object.
059   *
060   * @see #getSharedInstance
061   * @see #setSharedInstance
062   */
063  private static PopupFactory sharedFactory;
064
065
066  /**
067   * Constructs a new <code>PopupFactory</code>. Usually, a single
068   * <code>PopupFactory</code> is shared among multiple consumers
069   * of <code>Popup</code>. Use {@link #getSharedInstance} to retrieve
070   * the current factory.
071   */
072  public PopupFactory()
073  {
074    // Nothing to do here.
075  }
076
077
078  /**
079   * Sets the shared factory.
080   *
081   * @param factory the PopupFactory that future invocations of
082   *        {@link #getSharedInstance} will return.
083   *
084   * @throws IllegalArgumentException if <code>factory</code>
085   *         is <code>null</code>.
086   */
087  public static void setSharedInstance(PopupFactory factory)
088  {
089    if (factory == null)
090      throw new IllegalArgumentException();
091
092    /* Swing is not designed to be thread-safe, so there is no
093     * need to synchronize the access to the global variable.
094     */
095    sharedFactory = factory;
096  }
097
098
099  /**
100   * Retrieves the shared factory, creating a new factory if
101   * necessary.
102   *
103   * @return a <code>PopupFactory</code> that can be used
104   *         to create <code>Popup</code> objects.
105   */
106  public static PopupFactory getSharedInstance()
107  {
108    /* Swing is not designed to be thread-safe, so there is no
109     * need to synchronize the access to the global variable.
110     */
111    if (sharedFactory == null)
112      sharedFactory = new PopupFactory();
113
114    return sharedFactory;
115  }
116
117
118  /**
119   * Creates a new <code>Popup</code> given its owner,
120   * contents and the screen position where the popup
121   * will appear.
122   *
123   * @param owner the Component to which <code>x</code> and
124   *        <code>y</code> are relative, or <code>null</code> for
125   *        placing the popup relative to the origin of the screen.
126   *
127   * @param contents the contents that will be displayed inside
128   *        the <code>Popup</code>.
129   *
130   * @param x the horizontal position where the Popup will appear.
131   *
132   * @param y the vertical position where the Popup will appear.
133   *
134   * @throws IllegalArgumentException if <code>contents</code>
135   *         is <code>null</code>.
136   */
137  public Popup getPopup(Component owner, Component contents,
138                        int x, int y)
139  {
140    Popup popup = null;
141    // By default we enable lightweight popups since they are more efficient
142    // than heavyweight popups.
143    boolean lightweightEnabled = true;
144    // Special case JPopupMenu here, since it supports a lightweightEnabled
145    // flag that we must respect.
146    if (contents instanceof JPopupMenu)
147      {
148        JPopupMenu menu = (JPopupMenu) contents;
149        lightweightEnabled = menu.isLightWeightPopupEnabled();
150      }
151
152    // If we have a root pane and the contents fits within the root pane and
153    // lightweight popups are enabled, than we can use a lightweight popup.
154    JRootPane root = SwingUtilities.getRootPane(owner);
155    if (root != null)
156      {
157        Point rootLoc = root.getLocationOnScreen();
158        Dimension contentsSize = contents.getSize();
159        Dimension rootSize = root.getSize();
160        if (x >= rootLoc.x && y > rootLoc.y
161            && (x - rootLoc.x) + contentsSize.width < rootSize.width
162            && (y - rootLoc.y) + contentsSize.height < rootSize.height)      
163          popup = new Popup.LightweightPopup(owner, contents, x, y);
164        else
165          popup = new Popup.JWindowPopup(owner, contents, x, y);
166      }
167    else
168      popup = new Popup.JWindowPopup(owner, contents, x, y);
169    return popup;
170  }
171}