1 /*

     2  * Copyright (c) 1998, 2014, 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 jdk.jshell;

    27 

    28 import com.sun.jdi.*;

    29 import com.sun.jdi.event.*;

    30 

    31 /**

    32  * Handler of Java Debug Interface events.

    33  * Adapted from jdb EventHandler; Handling of events not used by JShell stubbed out.

    34  */

    35 class JDIEventHandler implements Runnable {

    36 

    37     Thread thread;

    38     volatile boolean connected = true;

    39     boolean completed = false;

    40     String shutdownMessageKey;

    41     final JDIEnv env;

    42 

    43     JDIEventHandler(JDIEnv env) {

    44         this.env = env;

    45         this.thread = new Thread(this, "event-handler");

    46         this.thread.start();

    47     }

    48 

    49     synchronized void shutdown() {

    50         connected = false;  // force run() loop termination

    51         thread.interrupt();

    52         while (!completed) {

    53             try {wait();} catch (InterruptedException exc) {}

    54         }

    55     }

    56 

    57     @Override

    58     public void run() {

    59         EventQueue queue = env.vm().eventQueue();

    60         while (connected) {

    61             try {

    62                 EventSet eventSet = queue.remove();

    63                 boolean resumeStoppedApp = false;

    64                 EventIterator it = eventSet.eventIterator();

    65                 while (it.hasNext()) {

    66                     resumeStoppedApp |= handleEvent(it.nextEvent());

    67                 }

    68 

    69                 if (resumeStoppedApp) {

    70                     eventSet.resume();

    71                 }

    72             } catch (InterruptedException exc) {

    73                 // Do nothing. Any changes will be seen at top of loop.

    74             } catch (VMDisconnectedException discExc) {

    75                 handleDisconnectedException();

    76                 break;

    77             }

    78         }

    79         synchronized (this) {

    80             completed = true;

    81             notifyAll();

    82         }

    83     }

    84 

    85     private boolean handleEvent(Event event) {

    86         if (event instanceof ExceptionEvent) {

    87             exceptionEvent(event);

    88         } else if (event instanceof WatchpointEvent) {

    89             fieldWatchEvent(event);

    90         } else if (event instanceof MethodEntryEvent) {

    91             methodEntryEvent(event);

    92         } else if (event instanceof MethodExitEvent) {

    93             methodExitEvent(event);

    94         } else if (event instanceof ClassPrepareEvent) {

    95             classPrepareEvent(event);

    96         } else if (event instanceof ThreadStartEvent) {

    97             threadStartEvent(event);

    98         } else if (event instanceof ThreadDeathEvent) {

    99             threadDeathEvent(event);

   100         } else if (event instanceof VMStartEvent) {

   101             vmStartEvent(event);

   102             return true;

   103         } else {

   104             handleExitEvent(event);

   105         }

   106         return true;

   107     }

   108 

   109     private boolean vmDied = false;

   110 

   111     private void handleExitEvent(Event event) {

   112         if (event instanceof VMDeathEvent) {

   113             vmDied = true;

   114             shutdownMessageKey = "The application exited";

   115         } else if (event instanceof VMDisconnectEvent) {

   116             connected = false;

   117             if (!vmDied) {

   118                 shutdownMessageKey = "The application has been disconnected";

   119             }

   120         } else {

   121             throw new InternalError("Unexpected event type: " +

   122                     event.getClass());

   123         }

   124         env.shutdown();

   125     }

   126 

   127     synchronized void handleDisconnectedException() {

   128         /*

   129          * A VMDisconnectedException has happened while dealing with

   130          * another event. We need to flush the event queue, dealing only

   131          * with exit events (VMDeath, VMDisconnect) so that we terminate

   132          * correctly.

   133          */

   134         EventQueue queue = env.vm().eventQueue();

   135         while (connected) {

   136             try {

   137                 EventSet eventSet = queue.remove();

   138                 EventIterator iter = eventSet.eventIterator();

   139                 while (iter.hasNext()) {

   140                     handleExitEvent(iter.next());

   141                 }

   142             } catch (InterruptedException exc) {

   143                 // ignore

   144             } catch (InternalError exc) {

   145                 // ignore

   146             }

   147         }

   148     }

   149 

   150     private void vmStartEvent(Event event)  {

   151         VMStartEvent se = (VMStartEvent)event;

   152     }

   153 

   154     private void methodEntryEvent(Event event)  {

   155         MethodEntryEvent me = (MethodEntryEvent)event;

   156     }

   157 

   158     private void methodExitEvent(Event event)  {

   159         MethodExitEvent me = (MethodExitEvent)event;

   160     }

   161 

   162     private void fieldWatchEvent(Event event)  {

   163         WatchpointEvent fwe = (WatchpointEvent)event;

   164     }

   165 

   166     private void classPrepareEvent(Event event)  {

   167         ClassPrepareEvent cle = (ClassPrepareEvent)event;

   168     }

   169 

   170     private void exceptionEvent(Event event) {

   171         ExceptionEvent ee = (ExceptionEvent)event;

   172     }

   173 

   174     private void threadDeathEvent(Event event) {

   175         ThreadDeathEvent tee = (ThreadDeathEvent)event;

   176     }

   177 

   178     private void threadStartEvent(Event event) {

   179         ThreadStartEvent tse = (ThreadStartEvent)event;

   180     }

   181 }