Commit missing file

transport/src/main/java/io/netty/channel/socket/nio/AbstractNioWorkerPool.java

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+/*
+ * Copyright 2011 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 io.netty.channel.socket.nio;
+
+import io.netty.channel.Channel;
+import io.netty.channel.socket.Worker;
+import io.netty.util.ExternalResourceReleasable;
+import io.netty.util.internal.ExecutorUtil;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Abstract base class for {@link WorkerPool} implementations that create the {@link Worker}'s up-front and return them in a "fair" fashion when calling
+ * {@link #nextWorker()}
+ *
+ */
+public abstract class AbstractNioWorkerPool<E extends AbstractNioWorker> implements WorkerPool<E> , ExternalResourceReleasable {
+
+    private final AbstractNioWorker[] workers;
+    private final AtomicInteger workerIndex = new AtomicInteger();
+    private final Executor workerExecutor;
+    
+    /**
+     * Create a new instance
+     * 
+     * @param workerExecutor the {@link Executor} to use for the {@link Worker}'s
+     * @param allowShutdownOnIdle allow the {@link Worker}'s to shutdown when there is not {@link Channel} is registered with it
+     * @param workerCount the count of {@link Worker}'s to create
+     */
+    AbstractNioWorkerPool(Executor workerExecutor, int workerCount, boolean allowShutDownOnIdle) {
+        if (workerExecutor == null) {
+            throw new NullPointerException("workerExecutor");
+        }
+        if (workerCount <= 0) {
+            throw new IllegalArgumentException(
+                    "workerCount (" + workerCount + ") " +
+                    "must be a positive integer.");
+        }        
+        workers = new AbstractNioWorker[workerCount];
+
+        for (int i = 0; i < workers.length; i++) {
+            workers[i] = createWorker(workerExecutor, allowShutDownOnIdle);
+        }
+        this.workerExecutor = workerExecutor;
+
+    }
+
+    /**
+     * Create a new {@link Worker} which uses the given {@link Executor} to service IO
+     * 
+     * 
+     * @param executor the {@link Executor} to use
+     * @param allowShutdownOnIdle allow the {@link Worker} to shutdown when there is not {@link Channel} is registered with it
+     * @return worker the new {@link Worker} 
+     */
+    protected abstract E createWorker(Executor executor, boolean allowShutdownOnIdle);
+
+    @SuppressWarnings("unchecked")
+    public E nextWorker() {
+        return (E) workers[Math.abs(workerIndex.getAndIncrement() % workers.length)];
+    }
+
+    @Override
+    public void releaseExternalResources() {
+        ExecutorUtil.terminate(workerExecutor);
+    }
+
+}