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 gnu.java.lang.CPStringBuilder;
042    
043    import java.awt.AWTEvent;
044    import java.beans.PropertyChangeEvent;
045    
046    import javax.accessibility.Accessible;
047    import javax.accessibility.AccessibleContext;
048    import javax.accessibility.AccessibleRole;
049    import javax.swing.plaf.ToolTipUI;
050    
051    /**
052     * This class is used to display ToolTips. ToolTips are small floating windows
053     * that display text when the mouse comes to rest over a Component. ToolTips
054     * are set for JComponents using JComponent.setToolTipText(String).
055     */
056    public class JToolTip extends JComponent implements Accessible
057    {
058    
059      private static final long serialVersionUID = -1138929898906751643L;
060    
061      /**
062       * Provides the accessibility features for the <code>JToolTip</code>
063       * component.
064       */
065      protected class AccessibleJToolTip extends AccessibleJComponent
066      {
067        private static final long serialVersionUID = -6222548177795408476L;
068    
069        /**
070         * Creates a new AccessibleJToolTip object.
071         */
072        protected AccessibleJToolTip()
073        {
074          // Nothing to do here.
075        }
076    
077        /**
078         * Returns a description for the accessible component.
079         *
080         * @return A description for the accessible component.
081         */
082        public String getAccessibleDescription()
083        {
084          String result = super.getAccessibleDescription();
085          if (result == null)
086            result = text;
087          return result;
088        }
089    
090        /**
091         * Returns the accessible role for the <code>JToolTip</code> component.
092         *
093         * @return {@link AccessibleRole#TOOL_TIP}.
094         */
095        public AccessibleRole getAccessibleRole()
096        {
097          return AccessibleRole.TOOL_TIP;
098        }
099      }
100    
101      /** The text to display in the JToolTip. */
102      String text;
103    
104      /** The component that the tool tip is associated with. */
105      JComponent component;
106    
107      /**
108       * Creates a new <code>JToolTip</code> instance.
109       */
110      public JToolTip()
111      {
112        disableEvents(AWTEvent.MOUSE_EVENT_MASK);
113        updateUI();
114      }
115    
116      /**
117       * Returns the text displayed by the tool tip.
118       *
119       * @return The text (possibly <code>null</code>).
120       *
121       * @see #setTipText(String)
122       */
123      public String getTipText()
124      {
125        return text;
126      }
127    
128      /**
129       * Returns the object that provides accessibility features for this
130       * <code>JToolTip</code> component.
131       *
132       * @return The accessible context (an instance of {@link AccessibleJToolTip}).
133       */
134      public AccessibleContext getAccessibleContext()
135      {
136        if (accessibleContext == null)
137          accessibleContext = new AccessibleJToolTip();
138        return accessibleContext;
139      }
140    
141      /**
142       * Returns the component that the tool tip is associated with.
143       *
144       * @return The component (possibly <code>null</code>).
145       *
146       * @see #setComponent(JComponent)
147       */
148      public JComponent getComponent()
149      {
150        return component;
151      }
152    
153      /**
154       * Returns the current UI delegate for this component.
155       *
156       * @return The UI delegate.
157       */
158      public ToolTipUI getUI()
159      {
160        return (ToolTipUI) ui;
161      }
162    
163      /**
164       * Returns the string suffix used to identify the UI class, in this case
165       * <code>"ToolTipUI"</code>.
166       *
167       * @return <code>"ToolTipUI"</code>.
168       */
169      public String getUIClassID()
170      {
171        return "ToolTipUI";
172      }
173    
174      /**
175       * Returns a string describing the attributes for the <code>JToolTip</code>
176       * component, for use in debugging.  The return value is guaranteed to be
177       * non-<code>null</code>, but the format of the string may vary between
178       * implementations.
179       *
180       * @return A string describing the attributes of the <code>JToolTip</code>.
181       */
182      protected String paramString()
183      {
184        CPStringBuilder sb = new CPStringBuilder(super.paramString());
185        sb.append(",tiptext=");
186        if (text != null)
187          sb.append(text);
188        return sb.toString();
189      }
190    
191      /**
192       * Sets the component that the tool tip is associated with and sends a
193       * {@link PropertyChangeEvent} (with the property name 'component') to all
194       * registered listeners.
195       *
196       * @param c  the component (<code>null</code> permitted).
197       *
198       * @see #getComponent()
199       */
200      public void setComponent(JComponent c)
201      {
202        JComponent oldValue = component;
203        component = c;
204        firePropertyChange("component", oldValue, c);
205      }
206    
207      /**
208       * Sets the text to be displayed by the tool tip and sends a
209       * {@link PropertyChangeEvent} (with the property name 'tiptext') to all
210       * registered listeners.
211       *
212       * @param tipText the text (<code>null</code> permitted).
213       *
214       * @see #getTipText()
215       */
216      public void setTipText(String tipText)
217      {
218        String oldValue = text;
219        text = tipText;
220        firePropertyChange("tiptext", oldValue, tipText);
221      }
222    
223      /**
224       * This method resets the UI used to the Look and Feel default.
225       */
226      public void updateUI()
227      {
228        setUI((ToolTipUI) UIManager.getUI(this));
229      }
230    
231      /**
232       * Returns <code>true</code> if the component is guaranteed to be painted
233       * on top of others. This returns false by default and is overridden by
234       * components like JMenuItem, JPopupMenu and JToolTip to return true for
235       * added efficiency.
236       *
237       * @return <code>true</code> if the component is guaranteed to be painted
238       *         on top of others
239       */
240      boolean onTop()
241      {
242        return true;
243      }
244    }