Fix warnings/javadocs in sal-distributed-datastore
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / OperationLimiter.java
1 /*
2  * Copyright (c) 2015 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.controller.cluster.datastore;
9
10 import akka.dispatch.OnComplete;
11 import com.google.common.annotations.VisibleForTesting;
12 import com.google.common.base.Preconditions;
13 import java.util.concurrent.Semaphore;
14 import java.util.concurrent.TimeUnit;
15 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
16 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
17 import org.slf4j.Logger;
18 import org.slf4j.LoggerFactory;
19
20 /**
21  * Class for limiting operations. It extends {@link OnComplete}, so we can plug it seamlessly
22  * into akka to release permits as futures complete.
23  */
24 public class OperationLimiter extends OnComplete<Object> {
25     private static final Logger LOG = LoggerFactory.getLogger(OperationLimiter.class);
26     private final TransactionIdentifier identifier;
27     private final long acquireTimeout;
28     private final Semaphore semaphore;
29     private final int maxPermits;
30
31     OperationLimiter(final TransactionIdentifier identifier, final int maxPermits, final long acquireTimeoutSeconds) {
32         this.identifier = Preconditions.checkNotNull(identifier);
33
34         Preconditions.checkArgument(acquireTimeoutSeconds >= 0);
35         this.acquireTimeout = TimeUnit.SECONDS.toNanos(acquireTimeoutSeconds);
36
37         Preconditions.checkArgument(maxPermits >= 0);
38         this.maxPermits = maxPermits;
39         this.semaphore = new Semaphore(maxPermits);
40     }
41
42     void acquire() {
43         acquire(1);
44     }
45
46     void acquire(final int acquirePermits) {
47         try {
48             if (!semaphore.tryAcquire(acquirePermits, acquireTimeout, TimeUnit.NANOSECONDS)) {
49                 LOG.warn("Failed to acquire operation permit for transaction {}", identifier);
50             }
51         } catch (InterruptedException e) {
52             if (LOG.isDebugEnabled()) {
53                 LOG.debug("Interrupted when trying to acquire operation permit for transaction {}", identifier, e);
54             } else {
55                 LOG.warn("Interrupted when trying to acquire operation permit for transaction {}", identifier);
56             }
57         }
58     }
59
60     @Override
61     public void onComplete(final Throwable throwable, final Object message) {
62         if (message instanceof BatchedModificationsReply) {
63             this.semaphore.release(((BatchedModificationsReply)message).getNumBatched());
64         } else {
65             this.semaphore.release();
66         }
67     }
68
69     public TransactionIdentifier getIdentifier() {
70         return identifier;
71     }
72
73     @VisibleForTesting
74     int availablePermits() {
75         return semaphore.availablePermits();
76     }
77
78     /**
79      * Release all the permits.
80      */
81     public void releaseAll() {
82         this.semaphore.release(maxPermits - availablePermits());
83     }
84 }

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