001: /*
002: * Copyright 1995-2007 Sun Microsystems, Inc. All Rights Reserved.
003: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004: *
005: * This code is free software; you can redistribute it and/or modify it
006: * under the terms of the GNU General Public License version 2 only, as
007: * published by the Free Software Foundation. Sun designates this
008: * particular file as subject to the "Classpath" exception as provided
009: * by Sun in the LICENSE file that accompanied this code.
010: *
011: * This code is distributed in the hope that it will be useful, but WITHOUT
012: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014: * version 2 for more details (a copy is included in the LICENSE file that
015: * accompanied this code).
016: *
017: * You should have received a copy of the GNU General Public License version
018: * 2 along with this work; if not, write to the Free Software Foundation,
019: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020: *
021: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022: * CA 95054 USA or visit www.sun.com if you need additional information or
023: * have any questions.
024: */
025: package java.awt;
026:
027: import javax.accessibility.*;
028:
029: /**
030: * <code>Panel</code> is the simplest container class. A panel
031: * provides space in which an application can attach any other
032: * component, including other panels.
033: * <p>
034: * The default layout manager for a panel is the
035: * <code>FlowLayout</code> layout manager.
036: *
037: * @version 1.46, 06/05/07
038: * @author Sami Shaio
039: * @see java.awt.FlowLayout
040: * @since JDK1.0
041: */
042: public class Panel extends Container implements Accessible {
043: private static final String base = "panel";
044: private static int nameCounter = 0;
045:
046: /*
047: * JDK 1.1 serialVersionUID
048: */
049: private static final long serialVersionUID = -2728009084054400034L;
050:
051: /**
052: * Creates a new panel using the default layout manager.
053: * The default layout manager for all panels is the
054: * <code>FlowLayout</code> class.
055: */
056: public Panel() {
057: this (new FlowLayout());
058: }
059:
060: /**
061: * Creates a new panel with the specified layout manager.
062: * @param layout the layout manager for this panel.
063: * @since JDK1.1
064: */
065: public Panel(LayoutManager layout) {
066: setLayout(layout);
067: }
068:
069: /**
070: * Construct a name for this component. Called by getName() when the
071: * name is null.
072: */
073: String constructComponentName() {
074: synchronized (Panel.class) {
075: return base + nameCounter++;
076: }
077: }
078:
079: /**
080: * Creates the Panel's peer. The peer allows you to modify the
081: * appearance of the panel without changing its functionality.
082: */
083:
084: public void addNotify() {
085: synchronized (getTreeLock()) {
086: if (peer == null)
087: peer = getToolkit().createPanel(this );
088: super .addNotify();
089: }
090: }
091:
092: /////////////////
093: // Accessibility support
094: ////////////////
095:
096: /**
097: * Gets the AccessibleContext associated with this Panel.
098: * For panels, the AccessibleContext takes the form of an
099: * AccessibleAWTPanel.
100: * A new AccessibleAWTPanel instance is created if necessary.
101: *
102: * @return an AccessibleAWTPanel that serves as the
103: * AccessibleContext of this Panel
104: * @since 1.3
105: */
106: public AccessibleContext getAccessibleContext() {
107: if (accessibleContext == null) {
108: accessibleContext = new AccessibleAWTPanel();
109: }
110: return accessibleContext;
111: }
112:
113: /**
114: * This class implements accessibility support for the
115: * <code>Panel</code> class. It provides an implementation of the
116: * Java Accessibility API appropriate to panel user-interface elements.
117: * @since 1.3
118: */
119: protected class AccessibleAWTPanel extends AccessibleAWTContainer {
120:
121: private static final long serialVersionUID = -6409552226660031050L;
122:
123: /**
124: * Get the role of this object.
125: *
126: * @return an instance of AccessibleRole describing the role of the
127: * object
128: */
129: public AccessibleRole getAccessibleRole() {
130: return AccessibleRole.PANEL;
131: }
132: }
133:
134: }
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