openflowplugin-impl/src/main/java/org/opendaylight/openflowplugin/impl/lifecycle/GuardedContextImpl.java

   1 /*
   2  * Copyright (c) 2017 Pantheon Technologies s.r.o. 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.openflowplugin.impl.lifecycle;
   9
  10 import static com.google.common.util.concurrent.Service.State.FAILED;
  11 import static com.google.common.util.concurrent.Service.State.NEW;
  12 import static com.google.common.util.concurrent.Service.State.RUNNING;
  13 import static com.google.common.util.concurrent.Service.State.STARTING;
  14 import static com.google.common.util.concurrent.Service.State.STOPPING;
  15 import static com.google.common.util.concurrent.Service.State.TERMINATED;
  16
  17 import com.google.common.util.concurrent.FutureCallback;
  18 import com.google.common.util.concurrent.Futures;
  19 import com.google.common.util.concurrent.ListenableFuture;
  20 import com.google.common.util.concurrent.Monitor;
  21 import com.google.common.util.concurrent.Monitor.Guard;
  22 import com.google.common.util.concurrent.MoreExecutors;
  23 import com.google.common.util.concurrent.Service;
  24 import java.util.function.Function;
  25 import javax.annotation.Nonnull;
  26 import org.opendaylight.mdsal.singleton.common.api.ServiceGroupIdentifier;
  27 import org.opendaylight.openflowplugin.api.openflow.OFPContext;
  28 import org.opendaylight.openflowplugin.api.openflow.device.DeviceInfo;
  29 import org.opendaylight.openflowplugin.api.openflow.lifecycle.ContextChainMastershipWatcher;
  30 import org.opendaylight.openflowplugin.api.openflow.lifecycle.GuardedContext;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33
  34 public class GuardedContextImpl implements GuardedContext {
  35     private static final Logger LOG = LoggerFactory.getLogger(GuardedContextImpl.class);
  36
  37     private final Monitor monitor = new Monitor();
  38     private final OFPContext delegate;
  39     private Service.State state = NEW;
  40
  41     private final Guard isStartable = new Guard(monitor) {
  42         @Override
  43         public boolean isSatisfied() {
  44             return state == NEW || state == TERMINATED;
  45         }
  46     };
  47
  48     private final Guard isStoppable = new Guard(monitor) {
  49         @Override
  50         public boolean isSatisfied() {
  51             return state.compareTo(RUNNING) <= 0;
  52         }
  53     };
  54
  55     private final Guard isCloseable = new Guard(monitor) {
  56         @Override
  57         public boolean isSatisfied() {
  58             return state != FAILED;
  59         }
  60     };
  61
  62     GuardedContextImpl(final OFPContext delegate) {
  63         this.delegate = delegate;
  64     }
  65
  66     @Override
  67     public Service.State state() {
  68         monitor.enter();
  69         final Service.State stateSnapshot = state;
  70         monitor.leave();
  71         return stateSnapshot;
  72     }
  73
  74     @Override
  75     public <T> T map(final Function<OFPContext, T> transformer) {
  76         return transformer.apply(delegate);
  77     }
  78
  79     @Override
  80     public void instantiateServiceInstance() {
  81         if (monitor.enterIf(isStartable)) {
  82             try {
  83                 LOG.info("Starting {} service for node {}", this, getDeviceInfo());
  84                 state = STARTING;
  85                 delegate.instantiateServiceInstance();
  86                 state = RUNNING;
  87             } finally {
  88                 monitor.leave();
  89             }
  90         } else {
  91             throw new IllegalStateException("Service " + this + " has already been started");
  92         }
  93     }
  94
  95     @Override
  96     @SuppressWarnings("checkstyle:IllegalCatch")
  97     public ListenableFuture<?> closeServiceInstance() {
  98         ListenableFuture<?> result = Futures.immediateFuture(null);
  99
 100         if (monitor.enterIf(isStoppable)) {
 101             try {
 102                 LOG.info("Stopping {} service for node {}", this, getDeviceInfo());
 103                 state = STOPPING;
 104                 final ListenableFuture<?> resultFuture = delegate.closeServiceInstance();
 105
 106                 Futures.addCallback(resultFuture, new FutureCallback<Object>() {
 107                     @Override
 108                     public void onSuccess(final Object result) {
 109                         state = TERMINATED;
 110                     }
 111
 112                     @Override
 113                     public void onFailure(final Throwable throwable) {
 114                         state = TERMINATED;
 115                     }
 116                 }, MoreExecutors.directExecutor());
 117
 118                 result = resultFuture;
 119             } catch (final Exception e) {
 120                 result = Futures.immediateFailedFuture(e);
 121             } finally {
 122                 monitor.leave();
 123             }
 124         }
 125
 126         state = TERMINATED;
 127         return result;
 128     }
 129
 130     @Nonnull
 131     @Override
 132     public ServiceGroupIdentifier getIdentifier() {
 133         return delegate.getIdentifier();
 134     }
 135
 136     @Override
 137     public String toString() {
 138         return delegate.getClass().getSimpleName() + "[" + state + "]";
 139     }
 140
 141     @Override
 142     public DeviceInfo getDeviceInfo() {
 143         return delegate.getDeviceInfo();
 144     }
 145
 146     @Override
 147     public void registerMastershipWatcher(@Nonnull final ContextChainMastershipWatcher contextChainMastershipWatcher) {
 148         delegate.registerMastershipWatcher(contextChainMastershipWatcher);
 149     }
 150
 151     @Override
 152     public void close() {
 153         if (monitor.enterIf(isCloseable)) {
 154             try {
 155                 LOG.info("Terminating {} service for node {}", this, getDeviceInfo());
 156                 state = FAILED;
 157                 delegate.close();
 158             } finally {
 159                 monitor.leave();
 160             }
 161         }
 162     }
 163 }