001    /* BasicComboBoxRenderer.java --
002       Copyright (C) 2004, 2005  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.plaf.basic;
040    
041    import java.awt.Component;
042    import java.awt.Dimension;
043    import java.io.Serializable;
044    
045    import javax.swing.Icon;
046    import javax.swing.JComboBox;
047    import javax.swing.JLabel;
048    import javax.swing.JList;
049    import javax.swing.ListCellRenderer;
050    import javax.swing.border.Border;
051    import javax.swing.border.EmptyBorder;
052    
053    /**
054     * A renderer for a {@link JComboBox}. 
055     *
056     * @author Olga Rodimina
057     */
058    public class BasicComboBoxRenderer 
059      extends JLabel 
060      implements ListCellRenderer, Serializable
061    {
062      /**
063       * A shared border instance for all renderers.
064       */
065      protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
066    
067      /**
068       * Creates a new <code>BasicComboBoxRenderer</code> object.
069       */
070      public BasicComboBoxRenderer()
071      {
072        setOpaque(true);
073        setBorder(noFocusBorder);
074      }
075    
076      /**
077       * Returns preferredSize of the renderer
078       * 
079       * @return preferredSize of the renderer
080       */
081      public Dimension getPreferredSize()
082      {
083        if (this.getText() != null && ! this.getText().equals(""))
084          return super.getPreferredSize();
085        else
086          {
087            // If the combo box option's text is empty or null, it won't size
088            // properly (ie, it'll be way too short)... so we throw in a dummy
089            // space to trick the superclass's sizing methods.
090            String oldText = this.getText();
091            this.setText(" ");
092            Dimension d = super.getPreferredSize();
093            this.setText(oldText);
094            return d;
095          }
096      }
097    
098      /**
099       * Returns a component that has been configured to display the given
100       * <code>value</code>.
101       *
102       * @param list List of items for which to the background and foreground
103       *        colors
104       * @param value object that should be rendered in the cell
105       * @param index index of the cell in the list of items.
106       * @param isSelected draw cell highlighted if isSelected is true
107       * @param cellHasFocus draw focus rectangle around cell if the cell has
108       *        focus
109       *
110       * @return Component that will be used to draw the desired cell.
111       */
112      public Component getListCellRendererComponent(JList list, Object value,
113                                                    int index, boolean isSelected,
114                                                    boolean cellHasFocus)
115      {
116        if (isSelected)
117          {
118            setBackground(list.getSelectionBackground());
119            setForeground(list.getSelectionForeground());
120          }
121        else
122          {
123            setBackground(list.getBackground());
124            setForeground(list.getForeground());
125          }
126        setFont(list.getFont());
127    
128        if (value instanceof Icon)
129          setIcon((Icon) value);
130        else
131          setText(value == null ? "" : value.toString());
132    
133        return this;
134      }
135    
136      /**
137       * A subclass of {@link BasicComboBoxRenderer} that implements the
138       * {@link javax.swing.plaf.UIResource} interface.
139       */
140      public static class UIResource extends BasicComboBoxRenderer
141        implements javax.swing.plaf.UIResource
142      {
143        /**
144         * Creates a new <code>UIResource</code> object.
145         */
146        public UIResource()
147        {
148          // Nothing to do here.
149        }
150      }
151    }