1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package javax.swing;
26
27 import java.awt.*;
28 import java.awt.event.*;
29 import java.io.*;
30 import java.beans.PropertyChangeListener;
31 import java.util.Locale;
32 import java.util.Vector;
33
34 import javax.accessibility.*;
35
36 /**
37 * This class is inserted in between cell renderers and the components that
38 * use them. It just exists to thwart the repaint() and invalidate() methods
39 * which would otherwise propagate up the tree when the renderer was configured.
40 * It's used by the implementations of JTable, JTree, and JList. For example,
41 * here's how CellRendererPane is used in the code the paints each row
42 * in a JList:
43 * <pre>
44 * cellRendererPane = new CellRendererPane();
45 * ...
46 * Component rendererComponent = renderer.getListCellRendererComponent();
47 * renderer.configureListCellRenderer(dataModel.getElementAt(row), row);
48 * cellRendererPane.paintComponent(g, rendererComponent, this, x, y, w, h);
49 * </pre>
50 * <p>
51 * A renderer component must override isShowing() and unconditionally return
52 * true to work correctly because the Swing paint does nothing for components
53 * with isShowing false.
54 * <p>
55 * <strong>Warning:</strong>
56 * Serialized objects of this class will not be compatible with
57 * future Swing releases. The current serialization support is
58 * appropriate for short term storage or RMI between applications running
59 * the same version of Swing. As of 1.4, support for long term storage
60 * of all JavaBeans
61 * has been added to the <code>java.beans</code> package.
62 * Please see {@link java.beans.XMLEncoder}.
63 *
64 * @author Hans Muller
65 * @since 1.2
66 */
67 @SuppressWarnings("serial") // Same-version serialization only
68 public class CellRendererPane extends Container implements Accessible
69 {
70 /**
71 * Construct a CellRendererPane object.
72 */
73 public CellRendererPane() {
74 super();
75 setLayout(null);
76 setVisible(false);
77 }
78
79 /**
80 * Overridden to avoid propagating a invalidate up the tree when the
81 * cell renderer child is configured.
82 */
83 public void invalidate() { }
84
85
86 /**
87 * Shouldn't be called.
88 */
89 public void paint(Graphics g) { }
90
91
92 /**
93 * Shouldn't be called.
94 */
95 public void update(Graphics g) { }
96
97
98 /**
99 * If the specified component is already a child of this then we don't
100 * bother doing anything - stacking order doesn't matter for cell
101 * renderer components (CellRendererPane doesn't paint anyway).
102 */
103 protected void addImpl(Component x, Object constraints, int index) {
104 if (x.getParent() == this) {
105 return;
106 }
107 else {
108 super.addImpl(x, constraints, index);
109 }
110 }
111
112
113 /**
114 * Paint a cell renderer component c on graphics object g. Before the component
115 * is drawn it's reparented to this (if that's necessary), it's bounds
116 * are set to w,h and the graphics object is (effectively) translated to x,y.
117 * If it's a JComponent, double buffering is temporarily turned off. After
118 * the component is painted it's bounds are reset to -w, -h, 0, 0 so that, if
119 * it's the last renderer component painted, it will not start consuming input.
120 * The Container p is the component we're actually drawing on, typically it's
121 * equal to this.getParent(). If shouldValidate is true the component c will be
122 * validated before painted.
123 *
124 * @param g the {@code Graphics} object to draw on
125 * @param c the {@code Component} to draw
126 * @param p the {@code Container} component actually drawn on
127 * @param x an int specifying the left side of the area draw in, in pixels,
128 * measured from the left edge of the graphics context
129 * @param y an int specifying the top of the area to draw in, in pixels
130 * measured down from the top edge of the graphics context
131 * @param w an int specifying the width of the area draw in, in pixels
132 * @param h an int specifying the height of the area draw in, in pixels
133 * @param shouldValidate if true, component {@code c} will be validated
134 * before being painted
135 */
136 public void paintComponent(Graphics g, Component c, Container p, int x, int y, int w, int h, boolean shouldValidate) {
137 if (c == null) {
138 if (p != null) {
139 Color oldColor = g.getColor();
140 g.setColor(p.getBackground());
141 g.fillRect(x, y, w, h);
142 g.setColor(oldColor);
143 }
144 return;
145 }
146
147 if (c.getParent() != this) {
148 this.add(c);
149 }
150
151 c.setBounds(x, y, w, h);
152
153 if(shouldValidate) {
154 c.validate();
155 }
156
157 boolean wasDoubleBuffered = false;
158 if ((c instanceof JComponent) && ((JComponent)c).isDoubleBuffered()) {
159 wasDoubleBuffered = true;
160 ((JComponent)c).setDoubleBuffered(false);
161 }
162
163 Graphics cg = g.create(x, y, w, h);
164 try {
165 c.paint(cg);
166 }
167 finally {
168 cg.dispose();
169 }
170
171 if (wasDoubleBuffered && (c instanceof JComponent)) {
172 ((JComponent)c).setDoubleBuffered(true);
173 }
174
175 c.setBounds(-w, -h, 0, 0);
176 }
177
178
179 /**
180 * Calls this.paintComponent(g, c, p, x, y, w, h, false).
181 *
182 * @param g the {@code Graphics} object to draw on
183 * @param c the {@code Component} to draw
184 * @param p the {@code Container} component actually drawn on
185 * @param x an int specifying the left side of the area draw in, in pixels,
186 * measured from the left edge of the graphics context
187 * @param y an int specifying the top of the area to draw in, in pixels
188 * measured down from the top edge of the graphics context
189 * @param w an int specifying the width of the area draw in, in pixels
190 * @param h an int specifying the height of the area draw in, in pixels
191 */
192 public void paintComponent(Graphics g, Component c, Container p, int x, int y, int w, int h) {
193 paintComponent(g, c, p, x, y, w, h, false);
194 }
195
196
197 /**
198 * Calls this.paintComponent() with the rectangles x,y,width,height fields.
199 *
200 * @param g the {@code Graphics} object to draw on
201 * @param c the {@code Component} to draw
202 * @param p the {@code Container} component actually drawn on
203 * @param r the {@code Rectangle} to draw in
204 */
205 public void paintComponent(Graphics g, Component c, Container p, Rectangle r) {
206 paintComponent(g, c, p, r.x, r.y, r.width, r.height);
207 }
208
209
210 private void writeObject(ObjectOutputStream s) throws IOException {
211 removeAll();
212 s.defaultWriteObject();
213 }
214
215
216 /////////////////
217 // Accessibility support
218 ////////////////
219
220 /**
221 * {@code AccessibleContext} associated with this {@code CellRendererPan}
222 */
223 protected AccessibleContext accessibleContext = null;
224
225
226 /**
227 * Gets the AccessibleContext associated with this CellRendererPane.
228 * For CellRendererPanes, the AccessibleContext takes the form of an
229 * AccessibleCellRendererPane.
230 * A new AccessibleCellRendererPane instance is created if necessary.
231 *
232 * @return an AccessibleCellRendererPane that serves as the
233 * AccessibleContext of this CellRendererPane
234 */
235 public AccessibleContext getAccessibleContext() {
236 if (accessibleContext == null) {
237 accessibleContext = new AccessibleCellRendererPane();
238 }
239 return accessibleContext;
240 }
241
242 /**
243 * This class implements accessibility support for the
244 * <code>CellRendererPane</code> class.
245 */
246 protected class AccessibleCellRendererPane extends AccessibleAWTContainer {
247 // AccessibleContext methods
248 //
249 /**
250 * Get the role of this object.
251 *
252 * @return an instance of AccessibleRole describing the role of the
253 * object
254 * @see AccessibleRole
255 */
256 public AccessibleRole getAccessibleRole() {
257 return AccessibleRole.PANEL;
258 }
259 } // inner class AccessibleCellRendererPane
260 }