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    1   /*
    2    * Copyright (c) 1997, 2002, 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   
   26   package java.awt;
   27   
   28   /**
   29    * An interface for events that know how to dispatch themselves.
   30    * By implementing this interface an event can be placed upon the event
   31    * queue and its <code>dispatch()</code> method will be called when the event
   32    * is dispatched, using the <code>EventDispatchThread</code>.
   33    * <p>
   34    * This is a very useful mechanism for avoiding deadlocks. If
   35    * a thread is executing in a critical section (i.e., it has entered
   36    * one or more monitors), calling other synchronized code may
   37    * cause deadlocks. To avoid the potential deadlocks, an
   38    * <code>ActiveEvent</code> can be created to run the second section of
   39    * code at later time. If there is contention on the monitor,
   40    * the second thread will simply block until the first thread
   41    * has finished its work and exited its monitors.
   42    * <p>
   43    * For security reasons, it is often desirable to use an <code>ActiveEvent</code>
   44    * to avoid calling untrusted code from a critical thread. For
   45    * instance, peer implementations can use this facility to avoid
   46    * making calls into user code from a system thread. Doing so avoids
   47    * potential deadlocks and denial-of-service attacks.
   48    *
   49    * @author  Timothy Prinzing
   50    * @since   1.2
   51    */
   52   public interface ActiveEvent {
   53   
   54       /**
   55        * Dispatch the event to its target, listeners of the events source,
   56        * or do whatever it is this event is supposed to do.
   57        */
   58       public void dispatch();
   59   }

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