1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
/*
* Copyright 2015 Open Networking Laboratory
*
* 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 org.onosproject.store.consistent.impl;
import com.google.common.collect.Sets;
import com.google.common.util.concurrent.Futures;
import org.onlab.util.SharedExecutors;
import org.onosproject.store.service.DistributedQueue;
import org.onosproject.store.service.Serializer;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import static com.google.common.base.Preconditions.checkNotNull;
import static org.onosproject.store.consistent.impl.StateMachineUpdate.Target.QUEUE_PUSH;
/**
* DistributedQueue implementation that provides FIFO ordering semantics.
*
* @param <E> queue entry type
*/
public class DefaultDistributedQueue<E> implements DistributedQueue<E> {
private final String name;
private final Database database;
private final Serializer serializer;
private final Set<CompletableFuture<E>> pendingFutures = Sets.newIdentityHashSet();
private static final String PRIMITIVE_NAME = "distributedQueue";
private static final String SIZE = "size";
private static final String PUSH = "push";
private static final String POP = "pop";
private static final String PEEK = "peek";
private static final String ERROR_NULL_ENTRY = "Null entries are not allowed";
private final MeteringAgent monitor;
public DefaultDistributedQueue(String name,
Database database,
Serializer serializer,
boolean meteringEnabled) {
this.name = checkNotNull(name, "queue name cannot be null");
this.database = checkNotNull(database, "database cannot be null");
this.serializer = checkNotNull(serializer, "serializer cannot be null");
this.monitor = new MeteringAgent(PRIMITIVE_NAME, name, meteringEnabled);
this.database.registerConsumer(update -> {
SharedExecutors.getSingleThreadExecutor().execute(() -> {
if (update.target() == QUEUE_PUSH) {
List<Object> input = update.input();
String queueName = (String) input.get(0);
if (queueName.equals(name)) {
tryPoll();
}
}
});
});
}
@Override
public long size() {
final MeteringAgent.Context timer = monitor.startTimer(SIZE);
return Futures.getUnchecked(database.queueSize(name).whenComplete((r, e) -> timer.stop(e)));
}
@Override
public void push(E entry) {
checkNotNull(entry, ERROR_NULL_ENTRY);
final MeteringAgent.Context timer = monitor.startTimer(PUSH);
Futures.getUnchecked(database.queuePush(name, serializer.encode(entry))
.whenComplete((r, e) -> timer.stop(e)));
}
@Override
public CompletableFuture<E> pop() {
final MeteringAgent.Context timer = monitor.startTimer(POP);
return database.queuePop(name)
.whenComplete((r, e) -> timer.stop(e))
.thenCompose(v -> {
if (v != null) {
return CompletableFuture.<E>completedFuture(serializer.decode(v));
}
CompletableFuture<E> newPendingFuture = new CompletableFuture<>();
pendingFutures.add(newPendingFuture);
return newPendingFuture;
});
}
@Override
public E peek() {
final MeteringAgent.Context timer = monitor.startTimer(PEEK);
return Futures.getUnchecked(database.queuePeek(name)
.thenApply(v -> v != null ? serializer.<E>decode(v) : null)
.whenComplete((r, e) -> timer.stop(e)));
}
public String name() {
return name;
}
protected void tryPoll() {
Set<CompletableFuture<E>> completedFutures = Sets.newHashSet();
for (CompletableFuture<E> future : pendingFutures) {
E entry = Futures.getUnchecked(database.queuePop(name)
.thenApply(v -> v != null ? serializer.decode(v) : null));
if (entry != null) {
future.complete(entry);
completedFutures.add(future);
} else {
break;
}
}
pendingFutures.removeAll(completedFutures);
}
}
|
