Source for javax.swing.plaf.basic.BasicComboBoxRenderer

   1: /* BasicComboBoxRenderer.java --
   2:    Copyright (C) 2004, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package javax.swing.plaf.basic;
  40: 
  41: import java.awt.Component;
  42: import java.awt.Dimension;
  43: import java.io.Serializable;
  44: 
  45: import javax.swing.Icon;
  46: import javax.swing.JComboBox;
  47: import javax.swing.JLabel;
  48: import javax.swing.JList;
  49: import javax.swing.ListCellRenderer;
  50: import javax.swing.border.Border;
  51: import javax.swing.border.EmptyBorder;
  52: 
  53: /**
  54:  * A renderer for a {@link JComboBox}. 
  55:  *
  56:  * @author Olga Rodimina
  57:  */
  58: public class BasicComboBoxRenderer 
  59:   extends JLabel 
  60:   implements ListCellRenderer, Serializable
  61: {
  62:   /**
  63:    * A shared border instance for all renderers.
  64:    */
  65:   protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
  66: 
  67:   /**
  68:    * Creates a new <code>BasicComboBoxRenderer</code> object.
  69:    */
  70:   public BasicComboBoxRenderer()
  71:   {
  72:     setOpaque(true);
  73:     setBorder(noFocusBorder);
  74:   }
  75: 
  76:   /**
  77:    * Returns preferredSize of the renderer
  78:    * 
  79:    * @return preferredSize of the renderer
  80:    */
  81:   public Dimension getPreferredSize()
  82:   {
  83:     if (this.getText() != null && ! this.getText().equals(""))
  84:       return super.getPreferredSize();
  85:     else
  86:       {
  87:         // If the combo box option's text is empty or null, it won't size
  88:         // properly (ie, it'll be way too short)... so we throw in a dummy
  89:         // space to trick the superclass's sizing methods.
  90:         String oldText = this.getText();
  91:         this.setText(" ");
  92:         Dimension d = super.getPreferredSize();
  93:         this.setText(oldText);
  94:         return d;
  95:       }
  96:   }
  97: 
  98:   /**
  99:    * 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: }