opendaylight/commons/protocol-framework/src/main/java/org/opendaylight/protocol/framework/ProtocolSessionPromise.java

   1 /*
   2  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.protocol.framework;
   9
  10 import io.netty.bootstrap.Bootstrap;
  11 import io.netty.channel.ChannelFuture;
  12 import io.netty.channel.ChannelFutureListener;
  13 import io.netty.channel.ChannelOption;
  14 import io.netty.util.concurrent.DefaultPromise;
  15 import io.netty.util.concurrent.EventExecutor;
  16 import io.netty.util.concurrent.Future;
  17 import io.netty.util.concurrent.FutureListener;
  18 import io.netty.util.concurrent.Promise;
  19
  20 import java.net.InetSocketAddress;
  21
  22 import javax.annotation.concurrent.GuardedBy;
  23 import javax.annotation.concurrent.ThreadSafe;
  24
  25 import org.slf4j.Logger;
  26 import org.slf4j.LoggerFactory;
  27
  28 import com.google.common.base.Preconditions;
  29
  30 @ThreadSafe
  31 final class ProtocolSessionPromise<S extends ProtocolSession<?>> extends DefaultPromise<S> {
  32     private static final Logger LOG = LoggerFactory.getLogger(ProtocolSessionPromise.class);
  33     private final ReconnectStrategy strategy;
  34     private final InetSocketAddress address;
  35     private final Bootstrap b;
  36
  37     @GuardedBy("this")
  38     private Future<?> pending;
  39
  40     ProtocolSessionPromise(final EventExecutor executor, final InetSocketAddress address, final ReconnectStrategy strategy,
  41             final Bootstrap b) {
  42         super(executor);
  43         this.strategy = Preconditions.checkNotNull(strategy);
  44         this.address = Preconditions.checkNotNull(address);
  45         this.b = Preconditions.checkNotNull(b);
  46     }
  47
  48     synchronized void connect() {
  49         final Object lock = this;
  50
  51         try {
  52             final int timeout = this.strategy.getConnectTimeout();
  53
  54             LOG.debug("Promise {} attempting connect for {}ms", lock, timeout);
  55
  56             this.b.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, timeout);
  57             this.pending = this.b.connect(this.address).addListener(new ChannelFutureListener() {
  58                 @Override
  59                 public void operationComplete(final ChannelFuture cf) throws Exception {
  60                     synchronized (lock) {
  61
  62                         LOG.debug("Promise {} connection resolved", lock);
  63
  64                         // Triggered when a connection attempt is resolved.
  65                         Preconditions.checkState(ProtocolSessionPromise.this.pending.equals(cf));
  66
  67                         /*
  68                          * The promise we gave out could have been cancelled,
  69                          * which cascades to the connect getting cancelled,
  70                          * but there is a slight race window, where the connect
  71                          * is already resolved, but the listener has not yet
  72                          * been notified -- cancellation at that point won't
  73                          * stop the notification arriving, so we have to close
  74                          * the race here.
  75                          */
  76                         if (isCancelled()) {
  77                             if (cf.isSuccess()) {
  78                                 LOG.debug("Closing channel for cancelled promise {}", lock);
  79                                 cf.channel().close();
  80                             }
  81                             return;
  82                         }
  83
  84                         if (!cf.isSuccess()) {
  85                             LOG.debug("Attempt to connect to {} failed", ProtocolSessionPromise.this.address, cf.cause());
  86
  87                             final Future<Void> rf = ProtocolSessionPromise.this.strategy.scheduleReconnect(cf.cause());
  88                             rf.addListener(new FutureListener<Void>() {
  89                                 @Override
  90                                 public void operationComplete(final Future<Void> sf) {
  91                                     synchronized (lock) {
  92                                         // Triggered when a connection attempt is to be made.
  93                                         Preconditions.checkState(ProtocolSessionPromise.this.pending.equals(sf));
  94
  95                                         /*
  96                                          * The promise we gave out could have been cancelled,
  97                                          * which cascades to the reconnect attempt getting
  98                                          * cancelled, but there is a slight race window, where
  99                                          * the reconnect attempt is already enqueued, but the
 100                                          * listener has not yet been notified -- if cancellation
 101                                          * happens at that point, we need to catch it here.
 102                                          */
 103                                         if (!isCancelled()) {
 104                                             if (sf.isSuccess()) {
 105                                                 connect();
 106                                             } else {
 107                                                 setFailure(sf.cause());
 108                                             }
 109                                         }
 110                                     }
 111                                 }
 112                             });
 113
 114                             ProtocolSessionPromise.this.pending = rf;
 115                         } else {
 116                             LOG.debug("Promise {} connection successful", lock);
 117                         }
 118                     }
 119                 }
 120             });
 121         } catch (final Exception e) {
 122             LOG.info("Failed to connect to {}", e);
 123             setFailure(e);
 124         }
 125     }
 126
 127     @Override
 128     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
 129         if (super.cancel(mayInterruptIfRunning)) {
 130             this.pending.cancel(mayInterruptIfRunning);
 131             return true;
 132         }
 133
 134         return false;
 135     }
 136
 137     @Override
 138     public synchronized Promise<S> setSuccess(final S result) {
 139         LOG.debug("Promise {} completed", this);
 140         this.strategy.reconnectSuccessful();
 141         return super.setSuccess(result);
 142     }
 143 }