Throw an RejectedExecutionException if someone tries to register a Channel to an AbstractNioWorker that was shutdown before. Part of #582

src/main/java/org/jboss/netty/channel/socket/nio/AbstractNioWorker.java

@@ -35,6 +35,7 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReadWriteLock;
@@ -128,22 +129,18 @@ abstract class AbstractNioWorker implements Worker {
 
     void register(AbstractNioChannel<?> channel, ChannelFuture future) {
 
-        Runnable registerTask = createRegisterTask(channel, future);
-
         synchronized (startStopLock) {
+            if (selector == null) {
+                // the selector was null this means the Worker has already been shutdown.
+                throw new RejectedExecutionException("Worker has already been shutdown");
+            }
+            Runnable registerTask = createRegisterTask(channel, future);
 
             boolean offered = registerTaskQueue.offer(registerTask);
             assert offered;
 
             if (wakenUp.compareAndSet(false, true)) {
-                // wake up the selector to speed things
-                selector = this.selector;
-
-                // Check if the selector is not null to prevent NPE if selector was
-                // set to null from another thread. See #469
-                if (selector != null) {
-                    selector.wakeup();
-                }
+                selector.wakeup();
             }
 
         }

src/test/java/org/jboss/netty/channel/socket/nio/AbstractNioWorkerTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package org.jboss.netty.channel.socket.nio;
+
+import static org.easymock.EasyMock.*;
+import static junit.framework.Assert.*;
+
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.RejectedExecutionException;
+
+
+import org.jboss.netty.channel.ChannelFuture;
+import org.junit.Test;
+
+public abstract class AbstractNioWorkerTest {
+
+    @Test
+    public void testShutdownWorkerThrowsException() throws InterruptedException {
+        AbstractNioChannel<?> mockChannel = createMock(AbstractNioChannel.class);
+        replay(mockChannel);
+        
+        ChannelFuture mockFuture = createMock(ChannelFuture.class);
+        replay(mockFuture);
+
+        
+        ExecutorService executor = Executors.newCachedThreadPool();
+        AbstractNioWorker worker = createWorker(executor);
+
+        executor.shutdownNow();
+
+        // give the Selector time to detect the shutdown
+        Thread.sleep(SelectorUtil.DEFAULT_SELECT_TIMEOUT * 10);
+        try {
+            worker.register(mockChannel, mockFuture);
+            fail();
+        } catch (RejectedExecutionException e) {
+            // expected
+        }
+        verify(mockChannel, mockFuture);
+        reset(mockChannel, mockFuture);
+    }
+
+    protected abstract AbstractNioWorker createWorker(Executor executor);
+}

src/test/java/org/jboss/netty/channel/socket/nio/NioDatagramWorkerTest.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package org.jboss.netty.channel.socket.nio;
+
+import java.util.concurrent.Executor;
+
+public class NioDatagramWorkerTest extends AbstractNioWorkerTest {
+
+    protected AbstractNioWorker createWorker(Executor executor) {
+        return new NioDatagramWorker(executor);
+    }
+}

src/test/java/org/jboss/netty/channel/socket/nio/NioWorkerTest.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package org.jboss.netty.channel.socket.nio;
+
+import java.util.concurrent.Executor;
+
+public class NioWorkerTest extends AbstractNioWorkerTest {
+
+    protected AbstractNioWorker createWorker(Executor executor) {
+        return new NioWorker(executor);
+    }
+}