ICE-1593 Handling thread interrupts in Java

- Added Ice.BackgroundIO property to perform all IO in a non-user
  thread. This makes Ice for Java interrupt safe. This is implemented
  by the QueueRequestHanbler.
- EndpointHostResolver now uses an executor instead of a thread.
- Added java/demo/Ice/interrupt and java/test/Ice/interrupt.
- Made several changes that must be ported to C++ & C#.
  - InvocationTimeout exceptions can hang forever.
  - Connection establishment is always asynchronous.
  - RequestHandler.requestTimeout and asyncRequestTimeout have been
    renamed to requestCancel and asyncRequestCancel.

1 files changed, 33 insertions, 3 deletions

diff --git a/java/src/IceInternal/ThreadPoolWorkQueue.java b/java/src/IceInternal/ThreadPoolWorkQueue.java
index 3cf5bc4430e..c46fe75fd3a 100644
--- a/java/src/IceInternal/ThreadPoolWorkQueue.java
+++ b/java/src/IceInternal/ThreadPoolWorkQueue.java
@@ -9,12 +9,14 @@
 
 package IceInternal;
 
+import java.util.concurrent.ExecutorService;
+
 final class ThreadPoolWorkQueue extends EventHandler
 {
-    ThreadPoolWorkQueue(ThreadPool threadPool, Instance instance, Selector selector)
+    ThreadPoolWorkQueue(Instance instance, ThreadPool threadPool, Selector selector)
     {
+        _executor = instance.getQueueExecutor();
         _threadPool = threadPool;
-        _instance = instance;
         _selector = selector;
         _destroyed = false;
 
@@ -89,6 +91,7 @@ final class ThreadPoolWorkQueue extends EventHandler
         {
             throw new Ice.CommunicatorDestroyedException();
         }
+        assert(item != null);
         _workItems.add(item);
         postMessage();
     }
@@ -115,6 +118,7 @@ final class ThreadPoolWorkQueue extends EventHandler
             if(!_workItems.isEmpty())
             {
                 workItem = _workItems.removeFirst();
+                assert(workItem != null);
             }
             else
             {
@@ -158,6 +162,25 @@ final class ThreadPoolWorkQueue extends EventHandler
     public void
     postMessage()
     {
+        if(_executor != null)
+        {
+            _executor.submit(new Runnable() {
+
+                @Override
+                public void run()
+                {
+                    postMessageInternal();
+                }
+            });
+        }
+        else {
+            postMessageInternal();
+        }
+    }
+
+    private void
+    postMessageInternal()
+    {
         java.nio.ByteBuffer buf = java.nio.ByteBuffer.allocate(1);
         buf.put(0, (byte)0);
         while(buf.hasRemaining())
@@ -166,6 +189,13 @@ final class ThreadPoolWorkQueue extends EventHandler
             {
                 _fdIntrWrite.write(buf);
             }
+            //
+            // This is thrown if the thread is interrupted.
+            //
+            catch(java.nio.channels.ClosedChannelException ex)
+            {
+                break;
+            }
             catch(java.io.IOException ex)
             {
                 throw new Ice.SocketException(ex);
@@ -174,7 +204,6 @@ final class ThreadPoolWorkQueue extends EventHandler
     }
 
     private final ThreadPool _threadPool;
-    private final Instance _instance;
     private final Selector _selector;
     boolean _destroyed;
 
@@ -182,4 +211,5 @@ final class ThreadPoolWorkQueue extends EventHandler
     private java.nio.channels.WritableByteChannel _fdIntrWrite;
 
     private java.util.LinkedList<ThreadPoolWorkItem> _workItems = new java.util.LinkedList<ThreadPoolWorkItem>();
+    private ExecutorService _executor;
 }