Java tutorial
/* * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing; import java.util.List; import java.util.ArrayList; import java.util.Collection; import java.util.Iterator; import javax.swing.plaf.*; import javax.accessibility.*; import java.awt.Component; import java.awt.Container; import java.beans.JavaBean; import java.beans.BeanProperty; import java.io.ObjectOutputStream; import java.io.IOException; import java.beans.PropertyVetoException; import java.util.Set; import java.util.TreeSet; import java.util.LinkedHashSet; /** * A container used to create a multiple-document interface or a virtual desktop. * You create <code>JInternalFrame</code> objects and add them to the * <code>JDesktopPane</code>. <code>JDesktopPane</code> extends * <code>JLayeredPane</code> to manage the potentially overlapping internal * frames. It also maintains a reference to an instance of * <code>DesktopManager</code> that is set by the UI * class for the current look and feel (L&F). Note that <code>JDesktopPane</code> * does not support borders. * <p> * This class is normally used as the parent of <code>JInternalFrames</code> * to provide a pluggable <code>DesktopManager</code> object to the * <code>JInternalFrames</code>. The <code>installUI</code> of the * L&F specific implementation is responsible for setting the * <code>desktopManager</code> variable appropriately. * When the parent of a <code>JInternalFrame</code> is a <code>JDesktopPane</code>, * it should delegate most of its behavior to the <code>desktopManager</code> * (closing, resizing, etc). * <p> * For further documentation and examples see * <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/internalframe.html">How to Use Internal Frames</a>, * a section in <em>The Java Tutorial</em>. * <p> * <strong>Warning:</strong> Swing is not thread safe. For more * information see <a * href="package-summary.html#threading">Swing's Threading * Policy</a>. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @see JInternalFrame * @see JInternalFrame.JDesktopIcon * @see DesktopManager * * @author David Kloba * @since 1.2 */ @JavaBean(defaultProperty = "UI") @SuppressWarnings("serial") // Same-version serialization only public class JDesktopPane extends JLayeredPane implements Accessible { /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "DesktopPaneUI"; transient DesktopManager desktopManager; private transient JInternalFrame selectedFrame = null; /** * Indicates that the entire contents of the item being dragged * should appear inside the desktop pane. * * @see #OUTLINE_DRAG_MODE * @see #setDragMode */ public static final int LIVE_DRAG_MODE = 0; /** * Indicates that an outline only of the item being dragged * should appear inside the desktop pane. * * @see #LIVE_DRAG_MODE * @see #setDragMode */ public static final int OUTLINE_DRAG_MODE = 1; private int dragMode = LIVE_DRAG_MODE; private boolean dragModeSet = false; private transient List<JInternalFrame> framesCache; private boolean componentOrderCheckingEnabled = true; private boolean componentOrderChanged = false; /** * Creates a new <code>JDesktopPane</code>. */ public JDesktopPane() { setUIProperty("opaque", Boolean.TRUE); setFocusCycleRoot(true); setFocusTraversalPolicy(new LayoutFocusTraversalPolicy() { public Component getDefaultComponent(Container c) { JInternalFrame[] jifArray = getAllFrames(); Component comp = null; for (JInternalFrame jif : jifArray) { comp = jif.getFocusTraversalPolicy().getDefaultComponent(jif); if (comp != null) { break; } } return comp; } }); updateUI(); } /** * Returns the L&F object that renders this component. * * @return the <code>DesktopPaneUI</code> object that * renders this component */ public DesktopPaneUI getUI() { return (DesktopPaneUI) ui; } /** * Sets the L&F object that renders this component. * * @param ui the DesktopPaneUI L&F object * @see UIDefaults#getUI */ @BeanProperty(hidden = true, visualUpdate = true, description = "The UI object that implements the Component's LookAndFeel.") public void setUI(DesktopPaneUI ui) { super.setUI(ui); } /** * Sets the "dragging style" used by the desktop pane. * You may want to change to one mode or another for * performance or aesthetic reasons. * * @param dragMode the style of drag to use for items in the Desktop * * @see #LIVE_DRAG_MODE * @see #OUTLINE_DRAG_MODE * * @since 1.3 */ @BeanProperty(enumerationValues = { "JDesktopPane.LIVE_DRAG_MODE", "JDesktopPane.OUTLINE_DRAG_MODE" }, description = "Dragging style for internal frame children.") public void setDragMode(int dragMode) { int oldDragMode = this.dragMode; this.dragMode = dragMode; firePropertyChange("dragMode", oldDragMode, this.dragMode); dragModeSet = true; } /** * Gets the current "dragging style" used by the desktop pane. * @return either <code>Live_DRAG_MODE</code> or * <code>OUTLINE_DRAG_MODE</code> * @see #setDragMode * @since 1.3 */ public int getDragMode() { return dragMode; } /** * Returns the {@code DesktopManger} that handles * desktop-specific UI actions. * * @return the {@code DesktopManger} that handles desktop-specific * UI actions */ public DesktopManager getDesktopManager() { return desktopManager; } /** * Sets the <code>DesktopManger</code> that will handle * desktop-specific UI actions. This may be overridden by * {@code LookAndFeel}. * * @param d the <code>DesktopManager</code> to use */ @BeanProperty(description = "Desktop manager to handle the internal frames in the desktop pane.") public void setDesktopManager(DesktopManager d) { DesktopManager oldValue = desktopManager; desktopManager = d; firePropertyChange("desktopManager", oldValue, desktopManager); } /** * Notification from the <code>UIManager</code> that the L&F has changed. * Replaces the current UI object with the latest version from the * <code>UIManager</code>. * * @see JComponent#updateUI */ public void updateUI() { setUI((DesktopPaneUI) UIManager.getUI(this)); } /** * Returns the name of the L&F class that renders this component. * * @return the string "DesktopPaneUI" * @see JComponent#getUIClassID * @see UIDefaults#getUI */ @BeanProperty(bound = false) public String getUIClassID() { return uiClassID; } /** * Returns all <code>JInternalFrames</code> currently displayed in the * desktop. Returns iconified frames as well as expanded frames. * * @return an array of <code>JInternalFrame</code> objects */ @BeanProperty(bound = false) public JInternalFrame[] getAllFrames() { return getAllFrames(this).toArray(new JInternalFrame[0]); } private static Collection<JInternalFrame> getAllFrames(Container parent) { int i, count; Collection<JInternalFrame> results = new LinkedHashSet<>(); count = parent.getComponentCount(); for (i = 0; i < count; i++) { Component next = parent.getComponent(i); if (next instanceof JInternalFrame) { results.add((JInternalFrame) next); } else if (next instanceof JInternalFrame.JDesktopIcon) { JInternalFrame tmp = ((JInternalFrame.JDesktopIcon) next).getInternalFrame(); if (tmp != null) { results.add(tmp); } } else if (next instanceof Container) { results.addAll(getAllFrames((Container) next)); } } return results; } /** Returns the currently active <code>JInternalFrame</code> * in this <code>JDesktopPane</code>, or <code>null</code> * if no <code>JInternalFrame</code> is currently active. * * @return the currently active <code>JInternalFrame</code> or * <code>null</code> * @since 1.3 */ public JInternalFrame getSelectedFrame() { return selectedFrame; } /** Sets the currently active <code>JInternalFrame</code> * in this <code>JDesktopPane</code>. This method is used to bridge * the package gap between JDesktopPane and the platform implementation * code and should not be called directly. To visually select the frame * the client must call JInternalFrame.setSelected(true) to activate * the frame. * @see JInternalFrame#setSelected(boolean) * * @param f the internal frame that's currently selected * @since 1.3 */ public void setSelectedFrame(JInternalFrame f) { selectedFrame = f; } /** * Returns all <code>JInternalFrames</code> currently displayed in the * specified layer of the desktop. Returns iconified frames as well * expanded frames. * * @param layer an int specifying the desktop layer * @return an array of <code>JInternalFrame</code> objects * @see JLayeredPane */ public JInternalFrame[] getAllFramesInLayer(int layer) { Collection<JInternalFrame> allFrames = getAllFrames(this); Iterator<JInternalFrame> iterator = allFrames.iterator(); while (iterator.hasNext()) { if (iterator.next().getLayer() != layer) { iterator.remove(); } } return allFrames.toArray(new JInternalFrame[0]); } private List<JInternalFrame> getFrames() { Component c; Set<ComponentPosition> set = new TreeSet<ComponentPosition>(); for (int i = 0; i < getComponentCount(); i++) { c = getComponent(i); if (c instanceof JInternalFrame) { set.add(new ComponentPosition((JInternalFrame) c, getLayer(c), i)); } else if (c instanceof JInternalFrame.JDesktopIcon) { c = ((JInternalFrame.JDesktopIcon) c).getInternalFrame(); set.add(new ComponentPosition((JInternalFrame) c, getLayer(c), i)); } } List<JInternalFrame> frames = new ArrayList<JInternalFrame>(set.size()); for (ComponentPosition position : set) { frames.add(position.component); } return frames; } private static class ComponentPosition implements Comparable<ComponentPosition> { private final JInternalFrame component; private final int layer; private final int zOrder; ComponentPosition(JInternalFrame component, int layer, int zOrder) { this.component = component; this.layer = layer; this.zOrder = zOrder; } public int compareTo(ComponentPosition o) { int delta = o.layer - layer; if (delta == 0) { return zOrder - o.zOrder; } return delta; } } private JInternalFrame getNextFrame(JInternalFrame f, boolean forward) { verifyFramesCache(); if (f == null) { return getTopInternalFrame(); } int i = framesCache.indexOf(f); if (i == -1 || framesCache.size() == 1) { /* error */ return null; } if (forward) { // navigate to the next frame if (++i == framesCache.size()) { /* wrap */ i = 0; } } else { // navigate to the previous frame if (--i == -1) { /* wrap */ i = framesCache.size() - 1; } } return framesCache.get(i); } JInternalFrame getNextFrame(JInternalFrame f) { return getNextFrame(f, true); } private JInternalFrame getTopInternalFrame() { if (framesCache.size() == 0) { return null; } return framesCache.get(0); } private void updateFramesCache() { framesCache = getFrames(); } private void verifyFramesCache() { // If framesCache is dirty, then recreate it. if (componentOrderChanged) { componentOrderChanged = false; updateFramesCache(); } } /** * {@inheritDoc} */ @Override public void remove(Component comp) { super.remove(comp); updateFramesCache(); } /** * Selects the next <code>JInternalFrame</code> in this desktop pane. * * @param forward a boolean indicating which direction to select in; * <code>true</code> for forward, <code>false</code> for * backward * @return the JInternalFrame that was selected or <code>null</code> * if nothing was selected * @since 1.6 */ public JInternalFrame selectFrame(boolean forward) { JInternalFrame selectedFrame = getSelectedFrame(); JInternalFrame frameToSelect = getNextFrame(selectedFrame, forward); if (frameToSelect == null) { return null; } // Maintain navigation traversal order until an // external stack change, such as a click on a frame. setComponentOrderCheckingEnabled(false); if (forward && selectedFrame != null) { selectedFrame.moveToBack(); // For Windows MDI fidelity. } try { frameToSelect.setSelected(true); } catch (PropertyVetoException pve) { } setComponentOrderCheckingEnabled(true); return frameToSelect; } /* * Sets whether component order checking is enabled. * @param enable a boolean value, where <code>true</code> means * a change in component order will cause a change in the keyboard * navigation order. * @since 1.6 */ void setComponentOrderCheckingEnabled(boolean enable) { componentOrderCheckingEnabled = enable; } /** * {@inheritDoc} * @since 1.6 */ protected void addImpl(Component comp, Object constraints, int index) { checkComponentAttributes(comp); super.addImpl(comp, constraints, index); if (componentOrderCheckingEnabled) { if (comp instanceof JInternalFrame || comp instanceof JInternalFrame.JDesktopIcon) { componentOrderChanged = true; } } } private void checkComponentAttributes(Component comp) { if (comp instanceof JInternalFrame && ((JInternalFrame) comp).isIcon()) { ((JInternalFrame) comp).putClientProperty("wasIconOnce", Boolean.FALSE); } } /** * {@inheritDoc} * @since 1.6 */ public void remove(int index) { if (componentOrderCheckingEnabled) { Component comp = getComponent(index); if (comp instanceof JInternalFrame || comp instanceof JInternalFrame.JDesktopIcon) { componentOrderChanged = true; } } super.remove(index); } /** * {@inheritDoc} * @since 1.6 */ public void removeAll() { if (componentOrderCheckingEnabled) { int count = getComponentCount(); for (int i = 0; i < count; i++) { Component comp = getComponent(i); if (comp instanceof JInternalFrame || comp instanceof JInternalFrame.JDesktopIcon) { componentOrderChanged = true; break; } } } super.removeAll(); } /** * {@inheritDoc} * @since 1.6 */ public void setComponentZOrder(Component comp, int index) { super.setComponentZOrder(comp, index); if (componentOrderCheckingEnabled) { if (comp instanceof JInternalFrame || comp instanceof JInternalFrame.JDesktopIcon) { componentOrderChanged = true; } } } /** * See readObject() and writeObject() in JComponent for more * information about serialization in Swing. */ private void writeObject(ObjectOutputStream s) throws IOException { s.defaultWriteObject(); if (getUIClassID().equals(uiClassID)) { byte count = JComponent.getWriteObjCounter(this); JComponent.setWriteObjCounter(this, --count); if (count == 0 && ui != null) { ui.installUI(this); } } } void setUIProperty(String propertyName, Object value) { if (propertyName == "dragMode") { if (!dragModeSet) { setDragMode(((Integer) value).intValue()); dragModeSet = false; } } else { super.setUIProperty(propertyName, value); } } /** * Returns a string representation of this <code>JDesktopPane</code>. * This method is intended to be used only for debugging purposes, and the * content and format of the returned string may vary between * implementations. The returned string may be empty but may not * be <code>null</code>. * * @return a string representation of this <code>JDesktopPane</code> */ protected String paramString() { String desktopManagerString = (desktopManager != null ? desktopManager.toString() : ""); return super.paramString() + ",desktopManager=" + desktopManagerString; } ///////////////// // Accessibility support //////////////// /** * Gets the <code>AccessibleContext</code> associated with this * <code>JDesktopPane</code>. For desktop panes, the * <code>AccessibleContext</code> takes the form of an * <code>AccessibleJDesktopPane</code>. * A new <code>AccessibleJDesktopPane</code> instance is created if necessary. * * @return an <code>AccessibleJDesktopPane</code> that serves as the * <code>AccessibleContext</code> of this <code>JDesktopPane</code> */ @BeanProperty(bound = false) public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJDesktopPane(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JDesktopPane</code> class. It provides an implementation of the * Java Accessibility API appropriate to desktop pane user-interface * elements. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. */ @SuppressWarnings("serial") // Same-version serialization only protected class AccessibleJDesktopPane extends AccessibleJComponent { /** * Get the role of this object. * * @return an instance of AccessibleRole describing the role of the * object * @see AccessibleRole */ public AccessibleRole getAccessibleRole() { return AccessibleRole.DESKTOP_PANE; } } }