jdk/src/share/classes/java/awt/SystemTray.java
changeset 2 90ce3da70b43
child 1168 5f1d2fcfcd3e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/awt/SystemTray.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,496 @@
+/*
+ * Copyright 2005-2007 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.awt;
+
+import java.util.Vector;
+import java.awt.peer.SystemTrayPeer;
+import java.beans.PropertyChangeListener;
+import java.beans.PropertyChangeSupport;
+import sun.awt.AppContext;
+import sun.awt.SunToolkit;
+import sun.awt.HeadlessToolkit;
+import sun.security.util.SecurityConstants;
+
+/**
+ * The <code>SystemTray</code> class represents the system tray for a
+ * desktop.  On Microsoft Windows it is referred to as the "Taskbar
+ * Status Area", on Gnome it is referred to as the "Notification
+ * Area", on KDE it is referred to as the "System Tray".  The system
+ * tray is shared by all applications running on the desktop.
+ *
+ * <p> On some platforms the system tray may not be present or may not
+ * be supported, in this case {@link SystemTray#getSystemTray()}
+ * throws {@link UnsupportedOperationException}.  To detect whether the
+ * system tray is supported, use {@link SystemTray#isSupported}.
+ *
+ * <p>The <code>SystemTray</code> may contain one or more {@link
+ * TrayIcon TrayIcons}, which are added to the tray using the {@link
+ * #add} method, and removed when no longer needed, using the
+ * {@link #remove}.  <code>TrayIcon</code> consists of an
+ * image, a popup menu and a set of associated listeners.  Please see
+ * the {@link TrayIcon} class for details.
+ *
+ * <p>Every Java application has a single <code>SystemTray</code>
+ * instance that allows the app to interface with the system tray of
+ * the desktop while the app is running.  The <code>SystemTray</code>
+ * instance can be obtained from the {@link #getSystemTray} method.
+ * An application may not create its own instance of
+ * <code>SystemTray</code>.
+ *
+ * <p>The following code snippet demonstrates how to access
+ * and customize the system tray:
+ * <code>
+ * <pre>
+ *     {@link TrayIcon} trayIcon = null;
+ *     if (SystemTray.isSupported()) {
+ *         // get the SystemTray instance
+ *         SystemTray tray = SystemTray.{@link #getSystemTray};
+ *         // load an image
+ *         {@link java.awt.Image} image = {@link java.awt.Toolkit#getImage(String) Toolkit.getDefaultToolkit().getImage}(...);
+ *         // create a action listener to listen for default action executed on the tray icon
+ *         {@link java.awt.event.ActionListener} listener = new {@link java.awt.event.ActionListener ActionListener}() {
+ *             public void {@link java.awt.event.ActionListener#actionPerformed actionPerformed}({@link java.awt.event.ActionEvent} e) {
+ *                 // execute default action of the application
+ *                 // ...
+ *             }
+ *         };
+ *         // create a popup menu
+ *         {@link java.awt.PopupMenu} popup = new {@link java.awt.PopupMenu#PopupMenu PopupMenu}();
+ *         // create menu item for the default action
+ *         MenuItem defaultItem = new MenuItem(...);
+ *         defaultItem.addActionListener(listener);
+ *         popup.add(defaultItem);
+ *         /// ... add other items
+ *         // construct a TrayIcon
+ *         trayIcon = new {@link TrayIcon#TrayIcon(java.awt.Image, String, java.awt.PopupMenu) TrayIcon}(image, "Tray Demo", popup);
+ *         // set the TrayIcon properties
+ *         trayIcon.{@link TrayIcon#addActionListener(java.awt.event.ActionListener) addActionListener}(listener);
+ *         // ...
+ *         // add the tray image
+ *         try {
+ *             tray.{@link SystemTray#add(TrayIcon) add}(trayIcon);
+ *         } catch (AWTException e) {
+ *             System.err.println(e);
+ *         }
+ *         // ...
+ *     } else {
+ *         // disable tray option in your application or
+ *         // perform other actions
+ *         ...
+ *     }
+ *     // ...
+ *     // some time later
+ *     // the application state has changed - update the image
+ *     if (trayIcon != null) {
+ *         trayIcon.{@link TrayIcon#setImage(java.awt.Image) setImage}(updatedImage);
+ *     }
+ *     // ...
+ * </pre>
+ * </code>
+ *
+ * @since 1.6
+ * @see TrayIcon
+ *
+ * @author Bino George
+ * @author Denis Mikhalkin
+ * @author Sharon Zakhour
+ * @author Anton Tarasov
+ */
+public class SystemTray {
+    private static SystemTray systemTray;
+    private int currentIconID = 0; // each TrayIcon added gets a unique ID
+
+    transient private SystemTrayPeer peer;
+
+    /**
+     * Private <code>SystemTray</code> constructor.
+     *
+     */
+    private SystemTray() {
+        addNotify();
+    }
+
+    /**
+     * Gets the <code>SystemTray</code> instance that represents the
+     * desktop's tray area.  This always returns the same instance per
+     * application.  On some platforms the system tray may not be
+     * supported.  You may use the {@link #isSupported} method to
+     * check if the system tray is supported.
+     *
+     * <p>If a SecurityManager is installed, the AWTPermission
+     * {@code accessSystemTray} must be granted in order to get the
+     * {@code SystemTray} instance. Otherwise this method will throw a
+     * SecurityException.
+     *
+     * @return the <code>SystemTray</code> instance that represents
+     * the desktop's tray area
+     * @throws UnsupportedOperationException if the system tray isn't
+     * supported by the current platform
+     * @throws HeadlessException if
+     * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>
+     * @throws SecurityException if {@code accessSystemTray} permission
+     * is not granted
+     * @see #add(TrayIcon)
+     * @see TrayIcon
+     * @see #isSupported
+     * @see SecurityManager#checkPermission
+     * @see AWTPermission
+     */
+    public static SystemTray getSystemTray() {
+        checkSystemTrayAllowed();
+        if (GraphicsEnvironment.isHeadless()) {
+            throw new HeadlessException();
+        }
+
+        initializeSystemTrayIfNeeded();
+
+        if (!isSupported()) {
+            throw new UnsupportedOperationException(
+                "The system tray is not supported on the current platform.");
+        }
+
+        return systemTray;
+    }
+
+    /**
+     * Returns whether the system tray is supported on the current
+     * platform.  In addition to displaying the tray icon, minimal
+     * system tray support includes either a popup menu (see {@link
+     * TrayIcon#setPopupMenu(PopupMenu)}) or an action event (see
+     * {@link TrayIcon#addActionListener(ActionListener)}).
+     *
+     * <p>Developers should not assume that all of the system tray
+     * functionality is supported.  To guarantee that the tray icon's
+     * default action is always accessible, add the default action to
+     * both the action listener and the popup menu.  See the {@link
+     * SystemTray example} for an example of how to do this.
+     *
+     * <p><b>Note</b>: When implementing <code>SystemTray</code> and
+     * <code>TrayIcon</code> it is <em>strongly recommended</em> that
+     * you assign different gestures to the popup menu and an action
+     * event.  Overloading a gesture for both purposes is confusing
+     * and may prevent the user from accessing one or the other.
+     *
+     * @see #getSystemTray
+     * @return <code>false</code> if no system tray access is supported; this
+     * method returns <code>true</code> if the minimal system tray access is
+     * supported but does not guarantee that all system tray
+     * functionality is supported for the current platform
+     */
+    public static boolean isSupported() {
+        initializeSystemTrayIfNeeded();
+
+        if (Toolkit.getDefaultToolkit() instanceof SunToolkit) {
+
+            return ((SunToolkit)Toolkit.getDefaultToolkit()).isTraySupported();
+
+        } else if (Toolkit.getDefaultToolkit() instanceof HeadlessToolkit) {
+
+            return ((HeadlessToolkit)Toolkit.getDefaultToolkit()).isTraySupported();
+        }
+        return false;
+    }
+
+    /**
+     * Adds a <code>TrayIcon</code> to the <code>SystemTray</code>.
+     * The tray icon becomes visible in the system tray once it is
+     * added.  The order in which icons are displayed in a tray is not
+     * specified - it is platform and implementation-dependent.
+     *
+     * <p> All icons added by the application are automatically
+     * removed from the <code>SystemTray</code> upon application exit
+     * and also when the desktop system tray becomes unavailable.
+     *
+     * @param trayIcon the <code>TrayIcon</code> to be added
+     * @throws NullPointerException if <code>trayIcon</code> is
+     * <code>null</code>
+     * @throws IllegalArgumentException if the same instance of
+     * a <code>TrayIcon</code> is added more than once
+     * @throws AWTException if the desktop system tray is missing
+     * @see #remove(TrayIcon)
+     * @see #getSystemTray
+     * @see TrayIcon
+     * @see java.awt.Image
+     */
+    public void add(TrayIcon trayIcon) throws AWTException {
+        if (trayIcon == null) {
+            throw new NullPointerException("adding null TrayIcon");
+        }
+        TrayIcon[] oldArray = null, newArray = null;
+        Vector<TrayIcon> icons = null;
+        synchronized (this) {
+            oldArray = systemTray.getTrayIcons();
+            icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
+            if (icons == null) {
+                icons = new Vector<TrayIcon>(3);
+                AppContext.getAppContext().put(TrayIcon.class, icons);
+
+            } else if (icons.contains(trayIcon)) {
+                throw new IllegalArgumentException("adding TrayIcon that is already added");
+            }
+            icons.add(trayIcon);
+            newArray = systemTray.getTrayIcons();
+
+            trayIcon.setID(++currentIconID);
+        }
+        try {
+            trayIcon.addNotify();
+        } catch (AWTException e) {
+            icons.remove(trayIcon);
+            throw e;
+        }
+        firePropertyChange("trayIcons", oldArray, newArray);
+    }
+
+    /**
+     * Removes the specified <code>TrayIcon</code> from the
+     * <code>SystemTray</code>.
+     *
+     * <p> All icons added by the application are automatically
+     * removed from the <code>SystemTray</code> upon application exit
+     * and also when the desktop system tray becomes unavailable.
+     *
+     * <p> If <code>trayIcon</code> is <code>null</code> or was not
+     * added to the system tray, no exception is thrown and no action
+     * is performed.
+     *
+     * @param trayIcon the <code>TrayIcon</code> to be removed
+     * @see #add(TrayIcon)
+     * @see TrayIcon
+     */
+    public void remove(TrayIcon trayIcon) {
+        if (trayIcon == null) {
+            return;
+        }
+        TrayIcon[] oldArray = null, newArray = null;
+        synchronized (this) {
+            oldArray = systemTray.getTrayIcons();
+            Vector<TrayIcon> icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
+            // TrayIcon with no peer is not contained in the array.
+            if (icons == null || !icons.remove(trayIcon)) {
+                return;
+            }
+            trayIcon.removeNotify();
+            newArray = systemTray.getTrayIcons();
+        }
+        firePropertyChange("trayIcons", oldArray, newArray);
+    }
+
+    /**
+     * Returns an array of all icons added to the tray by this
+     * application.  You can't access the icons added by another
+     * application.  Some browsers partition applets in different
+     * code bases into separate contexts, and establish walls between
+     * these contexts.  In such a scenario, only the tray icons added
+     * from this context will be returned.
+     *
+     * <p> The returned array is a copy of the actual array and may be
+     * modified in any way without affecting the system tray.  To
+     * remove a <code>TrayIcon</code> from the
+     * <code>SystemTray</code>, use the {@link
+     * #remove(TrayIcon)} method.
+     *
+     * @return an array of all tray icons added to this tray, or an
+     * empty array if none has been added
+     * @see #add(TrayIcon)
+     * @see TrayIcon
+     */
+    public TrayIcon[] getTrayIcons() {
+        Vector<TrayIcon> icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
+        if (icons != null) {
+            return (TrayIcon[])icons.toArray(new TrayIcon[icons.size()]);
+        }
+        return new TrayIcon[0];
+    }
+
+    /**
+     * Returns the size, in pixels, of the space that a tray icon will
+     * occupy in the system tray.  Developers may use this methods to
+     * acquire the preferred size for the image property of a tray icon
+     * before it is created.  For convenience, there is a similar
+     * method {@link TrayIcon#getSize} in the <code>TrayIcon</code> class.
+     *
+     * @return the default size of a tray icon, in pixels
+     * @see TrayIcon#setImageAutoSize(boolean)
+     * @see java.awt.Image
+     * @see TrayIcon#getSize()
+     */
+    public Dimension getTrayIconSize() {
+        return peer.getTrayIconSize();
+    }
+
+    /**
+     * Adds a {@code PropertyChangeListener} to the list of listeners for the
+     * specific property. The following properties are currently supported:
+     * <p> </p>
+     * <table border=1 summary="SystemTray properties">
+     * <tr>
+     *    <th>Property</th>
+     *    <th>Description</th>
+     * </tr>
+     * <tr>
+     *    <td>{@code trayIcons}</td>
+     *    <td>The {@code SystemTray}'s array of {@code TrayIcon} objects.
+     *        The array is accessed via the {@link #getTrayIcons} method.<br>
+     *        This property is changed when a tray icon is added to (or removed
+     *        from) the system tray.<br> For example, this property is changed
+     *        when the system tray becomes unavailable on the desktop<br>
+     *        and the tray icons are automatically removed.</td>
+     * </tr>
+     * <tr>
+     *    <td>{@code systemTray}</td>
+     *    <td>This property contains {@code SystemTray} instance when the system tray
+     *        is available or <code>null</code> otherwise.<br> This property is changed
+     *        when the system tray becomes available or unavailable on the desktop.<br>
+     *        The property is accessed by the {@link #getSystemTray} method.</td>
+     * </tr>
+     * </table>
+     * <p> </p>
+     * The {@code listener} listens to property changes only in this context.
+     * <p>
+     * If {@code listener} is {@code null}, no exception is thrown
+     * and no action is performed.
+     *
+     * @param propertyName the specified property
+     * @param listener the property change listener to be added
+     *
+     * @see #removePropertyChangeListener
+     * @see #getPropertyChangeListeners
+     */
+    public synchronized void addPropertyChangeListener(String propertyName,
+                                                       PropertyChangeListener listener)
+    {
+        if (listener == null) {
+            return;
+        }
+        getCurrentChangeSupport().addPropertyChangeListener(propertyName, listener);
+    }
+
+    /**
+     * Removes a {@code PropertyChangeListener} from the listener list
+     * for a specific property.
+     * <p>
+     * The {@code PropertyChangeListener} must be from this context.
+     * <p>
+     * If {@code propertyName} or {@code listener} is {@code null} or invalid,
+     * no exception is thrown and no action is taken.
+     *
+     * @param propertyName the specified property
+     * @param listener the PropertyChangeListener to be removed
+     *
+     * @see #addPropertyChangeListener
+     * @see #getPropertyChangeListeners
+     */
+    public synchronized void removePropertyChangeListener(String propertyName,
+                                                          PropertyChangeListener listener)
+    {
+        if (listener == null) {
+            return;
+        }
+        getCurrentChangeSupport().removePropertyChangeListener(propertyName, listener);
+    }
+
+    /**
+     * Returns an array of all the listeners that have been associated
+     * with the named property.
+     * <p>
+     * Only the listeners in this context are returned.
+     *
+     * @param propertyName the specified property
+     * @return all of the {@code PropertyChangeListener}s associated with
+     *         the named property; if no such listeners have been added or
+     *         if {@code propertyName} is {@code null} or invalid, an empty
+     *         array is returned
+     *
+     * @see #addPropertyChangeListener
+     * @see #removePropertyChangeListener
+     */
+    public synchronized PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
+        return getCurrentChangeSupport().getPropertyChangeListeners(propertyName);
+    }
+
+
+    // ***************************************************************
+    // ***************************************************************
+
+
+    /**
+     * Support for reporting bound property changes for Object properties.
+     * This method can be called when a bound property has changed and it will
+     * send the appropriate PropertyChangeEvent to any registered
+     * PropertyChangeListeners.
+     *
+     * @param propertyName the property whose value has changed
+     * @param oldValue the property's previous value
+     * @param newValue the property's new value
+     */
+    private void firePropertyChange(String propertyName,
+                                    Object oldValue, Object newValue)
+    {
+        if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
+            return;
+        }
+        getCurrentChangeSupport().firePropertyChange(propertyName, oldValue, newValue);
+    }
+
+    /**
+     * Returns the current PropertyChangeSupport instance for the
+     * calling thread's context.
+     *
+     * @return this thread's context's PropertyChangeSupport
+     */
+    private synchronized PropertyChangeSupport getCurrentChangeSupport() {
+        PropertyChangeSupport changeSupport =
+            (PropertyChangeSupport)AppContext.getAppContext().get(SystemTray.class);
+
+        if (changeSupport == null) {
+            changeSupport = new PropertyChangeSupport(this);
+            AppContext.getAppContext().put(SystemTray.class, changeSupport);
+        }
+        return changeSupport;
+    }
+
+    synchronized void addNotify() {
+        if (peer == null) {
+            peer = ((SunToolkit)Toolkit.getDefaultToolkit()).createSystemTray(this);
+        }
+    }
+
+    static void checkSystemTrayAllowed() {
+        SecurityManager security = System.getSecurityManager();
+        if (security != null) {
+            security.checkPermission(SecurityConstants.ACCESS_SYSTEM_TRAY_PERMISSION);
+        }
+    }
+
+    private static void initializeSystemTrayIfNeeded() {
+        synchronized (SystemTray.class) {
+            if (systemTray == null) {
+                systemTray = new SystemTray();
+            }
+        }
+    }
+}