jdk/src/share/classes/java/awt/KeyEventDispatcher.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/awt/KeyEventDispatcher.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2000-2001 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.awt.event.KeyEvent;
+
+
+/**
+ * A KeyEventDispatcher cooperates with the current KeyboardFocusManager in the
+ * targeting and dispatching of all KeyEvents. KeyEventDispatchers registered
+ * with the current KeyboardFocusManager will receive KeyEvents before they are
+ * dispatched to their targets, allowing each KeyEventDispatcher to retarget
+ * the event, consume it, dispatch the event itself, or make other changes.
+ * <p>
+ * Note that KeyboardFocusManager itself implements KeyEventDispatcher. By
+ * default, the current KeyboardFocusManager will be the sink for all KeyEvents
+ * not dispatched by the registered KeyEventDispatchers. The current
+ * KeyboardFocusManager cannot be completely deregistered as a
+ * KeyEventDispatcher. However, if a KeyEventDispatcher reports that it
+ * dispatched the KeyEvent, regardless of whether it actually did so, the
+ * KeyboardFocusManager will take no further action with regard to the
+ * KeyEvent. (While it is possible for client code to register the current
+ * KeyboardFocusManager as a KeyEventDispatcher one or more times, this is
+ * usually unnecessary and not recommended.)
+ *
+ * @author David Mendenhall
+ *
+ * @see KeyboardFocusManager#addKeyEventDispatcher
+ * @see KeyboardFocusManager#removeKeyEventDispatcher
+ * @since 1.4
+ */
+public interface KeyEventDispatcher {
+
+    /**
+     * This method is called by the current KeyboardFocusManager requesting
+     * that this KeyEventDispatcher dispatch the specified event on its behalf.
+     * This KeyEventDispatcher is free to retarget the event, consume it,
+     * dispatch it itself, or make other changes. This capability is typically
+     * used to deliver KeyEvents to Components other than the focus owner. This
+     * can be useful when navigating children of non-focusable Windows in an
+     * accessible environment, for example. Note that if a KeyEventDispatcher
+     * dispatches the KeyEvent itself, it must use <code>redispatchEvent</code>
+     * to prevent the current KeyboardFocusManager from recursively requesting
+     * that this KeyEventDispatcher dispatch the event again.
+     * <p>
+     * If an implementation of this method returns <code>false</code>, then
+     * the KeyEvent is passed to the next KeyEventDispatcher in the chain,
+     * ending with the current KeyboardFocusManager. If an implementation
+     * returns <code>true</code>, the KeyEvent is assumed to have been
+     * dispatched (although this need not be the case), and the current
+     * KeyboardFocusManager will take no further action with regard to the
+     * KeyEvent. In such a case,
+     * <code>KeyboardFocusManager.dispatchEvent</code> should return
+     * <code>true</code> as well. If an implementation consumes the KeyEvent,
+     * but returns <code>false</code>, the consumed event will still be passed
+     * to the next KeyEventDispatcher in the chain. It is important for
+     * developers to check whether the KeyEvent has been consumed before
+     * dispatching it to a target. By default, the current KeyboardFocusManager
+     * will not dispatch a consumed KeyEvent.
+     *
+     * @param e the KeyEvent to dispatch
+     * @return <code>true</code> if the KeyboardFocusManager should take no
+     *         further action with regard to the KeyEvent; <code>false</code>
+     *         otherwise
+     * @see KeyboardFocusManager#redispatchEvent
+     */
+    boolean dispatchKeyEvent(KeyEvent e);
+}