001    /* JToolTip.java --
002       Copyright (C) 2002, 2004  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing;
040    
041    import java.awt.AWTEvent;
042    import java.beans.PropertyChangeEvent;
043    
044    import javax.accessibility.Accessible;
045    import javax.accessibility.AccessibleContext;
046    import javax.accessibility.AccessibleRole;
047    import javax.swing.plaf.ToolTipUI;
048    
049    /**
050     * This class is used to display ToolTips. ToolTips are small floating windows
051     * that display text when the mouse comes to rest over a Component. ToolTips
052     * are set for JComponents using JComponent.setToolTipText(String).
053     */
054    public class JToolTip extends JComponent implements Accessible
055    {
056    
057      private static final long serialVersionUID = -1138929898906751643L;
058    
059      /**
060       * Provides the accessibility features for the <code>JToolTip</code>
061       * component.
062       */
063      protected class AccessibleJToolTip extends AccessibleJComponent
064      {
065        private static final long serialVersionUID = -6222548177795408476L;
066    
067        /**
068         * Creates a new AccessibleJToolTip object.
069         */
070        protected AccessibleJToolTip()
071        {
072          // Nothing to do here.
073        }
074    
075        /**
076         * Returns a description for the accessible component.
077         *
078         * @return A description for the accessible component.
079         */
080        public String getAccessibleDescription()
081        {
082          String result = super.getAccessibleDescription();
083          if (result == null)
084            result = text;
085          return result;
086        }
087    
088        /**
089         * Returns the accessible role for the <code>JToolTip</code> component.
090         *
091         * @return {@link AccessibleRole#TOOL_TIP}.
092         */
093        public AccessibleRole getAccessibleRole()
094        {
095          return AccessibleRole.TOOL_TIP;
096        }
097      }
098    
099      /** The text to display in the JToolTip. */
100      String text;
101    
102      /** The component that the tool tip is associated with. */
103      JComponent component;
104    
105      /**
106       * Creates a new <code>JToolTip</code> instance.
107       */
108      public JToolTip()
109      {
110        disableEvents(AWTEvent.MOUSE_EVENT_MASK);
111        updateUI();
112      }
113    
114      /**
115       * Returns the text displayed by the tool tip.
116       *
117       * @return The text (possibly <code>null</code>).
118       * 
119       * @see #setTipText(String)
120       */
121      public String getTipText()
122      {
123        return text;
124      }
125    
126      /**
127       * Returns the object that provides accessibility features for this
128       * <code>JToolTip</code> component.
129       *
130       * @return The accessible context (an instance of {@link AccessibleJToolTip}).
131       */
132      public AccessibleContext getAccessibleContext()
133      {
134        if (accessibleContext == null)
135          accessibleContext = new AccessibleJToolTip();
136        return accessibleContext;
137      }
138    
139      /**
140       * Returns the component that the tool tip is associated with.
141       *
142       * @return The component (possibly <code>null</code>).
143       * 
144       * @see #setComponent(JComponent)
145       */
146      public JComponent getComponent()
147      {
148        return component;
149      }
150    
151      /**
152       * Returns the current UI delegate for this component.
153       *
154       * @return The UI delegate.
155       */
156      public ToolTipUI getUI()
157      {
158        return (ToolTipUI) ui;
159      }
160    
161      /**
162       * Returns the string suffix used to identify the UI class, in this case
163       * <code>"ToolTipUI"</code>.
164       *
165       * @return <code>"ToolTipUI"</code>.
166       */
167      public String getUIClassID()
168      {
169        return "ToolTipUI";
170      }
171    
172      /**
173       * Returns a string describing the attributes for the <code>JToolTip</code>
174       * component, for use in debugging.  The return value is guaranteed to be 
175       * non-<code>null</code>, but the format of the string may vary between
176       * implementations.
177       *
178       * @return A string describing the attributes of the <code>JToolTip</code>.
179       */
180      protected String paramString()
181      {
182        StringBuffer sb = new StringBuffer(super.paramString());
183        sb.append(",tiptext=");
184        if (text != null)
185          sb.append(text);
186        return sb.toString();
187      }
188    
189      /**
190       * Sets the component that the tool tip is associated with and sends a 
191       * {@link PropertyChangeEvent} (with the property name 'component') to all 
192       * registered listeners.
193       *
194       * @param c  the component (<code>null</code> permitted).
195       * 
196       * @see #getComponent()
197       */
198      public void setComponent(JComponent c)
199      {
200        JComponent oldValue = component;
201        component = c;
202        firePropertyChange("component", oldValue, c);
203      }
204    
205      /**
206       * Sets the text to be displayed by the tool tip and sends a 
207       * {@link PropertyChangeEvent} (with the property name 'tiptext') to all 
208       * registered listeners.
209       *
210       * @param tipText the text (<code>null</code> permitted).
211       * 
212       * @see #getTipText()
213       */
214      public void setTipText(String tipText)
215      {
216        String oldValue = text;
217        text = tipText;
218        firePropertyChange("tiptext", oldValue, tipText);
219      }
220    
221      /**
222       * This method resets the UI used to the Look and Feel default.
223       */
224      public void updateUI()
225      {
226        setUI((ToolTipUI) UIManager.getUI(this));
227      }
228    
229      /**
230       * Returns <code>true</code> if the component is guaranteed to be painted
231       * on top of others. This returns false by default and is overridden by
232       * components like JMenuItem, JPopupMenu and JToolTip to return true for
233       * added efficiency.
234       *
235       * @return <code>true</code> if the component is guaranteed to be painted
236       *         on top of others
237       */
238      boolean onTop()
239      {
240        return true;
241      }
242    }