| /** |
| * Copyright 2011, Big Switch Networks, Inc. |
| * Originally created by David Erickson, Stanford University |
| * |
| * Licensed 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 net.floodlightcontroller.core.internal; |
| |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| |
| import org.openflow.protocol.OFMessage; |
| import org.openflow.protocol.OFType; |
| |
| import net.floodlightcontroller.core.IOFSwitch; |
| import net.floodlightcontroller.threadpool.IThreadPoolService; |
| |
| /** |
| * A Future object used to retrieve asynchronous OFMessage replies. Unregisters |
| * and cancels itself by default after 60 seconds. This class is meant to be |
| * sub-classed and proper behavior added to the handleReply method, and |
| * termination of the Future to be handled in the isFinished method. |
| * |
| * @author David Erickson (daviderickson@cs.stanford.edu) |
| */ |
| public abstract class OFMessageFuture<V> implements Future<V> { |
| |
| protected IThreadPoolService threadPool; |
| protected volatile boolean canceled; |
| protected CountDownLatch latch; |
| protected OFType responseType; |
| protected volatile V result; |
| protected IOFSwitch sw; |
| protected Runnable timeoutTimer; |
| protected int transactionId; |
| protected static final long DEFAULT_TIMEOUT = 60; |
| protected static final TimeUnit DEFAULT_TIMEOUT_UNIT = TimeUnit.SECONDS; |
| |
| public OFMessageFuture(IThreadPoolService tp, |
| IOFSwitch sw, OFType responseType, int transactionId) { |
| this(tp, sw, responseType, transactionId, |
| DEFAULT_TIMEOUT, DEFAULT_TIMEOUT_UNIT); |
| } |
| |
| public OFMessageFuture(IThreadPoolService tp, |
| IOFSwitch sw, OFType responseType, int transactionId, long timeout, TimeUnit unit) { |
| this.threadPool = tp; |
| this.canceled = false; |
| this.latch = new CountDownLatch(1); |
| this.responseType = responseType; |
| this.sw = sw; |
| this.transactionId = transactionId; |
| |
| final OFMessageFuture<V> future = this; |
| timeoutTimer = new Runnable() { |
| @Override |
| public void run() { |
| if (timeoutTimer == this) |
| future.cancel(true); |
| } |
| }; |
| threadPool.getScheduledExecutor().schedule(timeoutTimer, timeout, unit); |
| } |
| |
| protected void unRegister() { |
| this.timeoutTimer = null; |
| } |
| |
| |
| public void deliverFuture(IOFSwitch sw, OFMessage msg) { |
| if (transactionId == msg.getXid()) { |
| handleReply(sw, msg); |
| if (isFinished()) { |
| unRegister(); |
| this.latch.countDown(); |
| } |
| } |
| } |
| |
| /** |
| * Used to handle the specific expected message this Future was reigstered |
| * for, the specified msg parameter is guaranteed to match the type and |
| * transaction id specified. |
| * @param sw |
| * @param msg |
| * @return |
| */ |
| protected abstract void handleReply(IOFSwitch sw, OFMessage msg); |
| |
| /** |
| * Called directly after handleReply, subclasses implement this method to |
| * indicate when the future can deregister itself from receiving future |
| * messages, and when it is safe to return the results to any waiting |
| * threads. |
| * @return when this Future has completed its work |
| */ |
| protected abstract boolean isFinished(); |
| |
| /* (non-Javadoc) |
| * @see java.util.concurrent.Future#cancel(boolean) |
| */ |
| @Override |
| public boolean cancel(boolean mayInterruptIfRunning) { |
| if (isDone()) { |
| return false; |
| } else { |
| unRegister(); |
| canceled = true; |
| this.latch.countDown(); |
| return !isDone(); |
| } |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.concurrent.Future#isCancelled() |
| */ |
| @Override |
| public boolean isCancelled() { |
| return canceled; |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.concurrent.Future#isDone() |
| */ |
| @Override |
| public boolean isDone() { |
| return this.latch.getCount() == 0; |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.concurrent.Future#get() |
| */ |
| @Override |
| public V get() throws InterruptedException, ExecutionException { |
| this.latch.await(); |
| return result; |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.concurrent.Future#get(long, java.util.concurrent.TimeUnit) |
| */ |
| @Override |
| public V get(long timeout, TimeUnit unit) throws InterruptedException, |
| ExecutionException, TimeoutException { |
| this.latch.await(timeout, unit); |
| return result; |
| } |
| |
| public int getTransactionId() { |
| return transactionId; |
| } |
| |
| public void setTransactionId(int transactionId) { |
| this.transactionId = transactionId; |
| } |
| } |