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
|
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.jdisc.handler;
import com.yahoo.concurrent.CompletableFutures;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* <p>This class implements a Future<Boolean> that is a conjunction of zero or more other Future<Boolean>s,
* i.e. it evaluates to <code>true</code> if, and only if, all its operands evaluate to <code>true</code>. To use this class,
* simply create an instance of it and add operands to it using the {@link #addOperand(CompletableFuture)} method.</p>
*
* @author Simon Thoresen Hult
*/
final class FutureConjunction implements Future<Boolean> {
private final List<CompletableFuture<Boolean>> operands = new LinkedList<>();
/**
* <p>Adds a {@link CompletableFuture} to this conjunction. This can be called at any time, even after having called
* {@link #get()} previously.</p>
*
* @param operand The operand to add to this conjunction.
*/
public void addOperand(CompletableFuture<Boolean> operand) {
operands.add(operand);
}
public void addListener(Runnable listener, Executor executor) {
CompletableFutures.allOf(operands)
.whenCompleteAsync((__, ___) -> listener.run(), executor);
}
CompletableFuture<Boolean> completableFuture() {
return CompletableFutures.allOf(operands)
.thenApply(ops -> ops.stream().allMatch(bool -> bool));
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
boolean ret = true;
for (Future<Boolean> op : operands) {
if (!op.cancel(mayInterruptIfRunning)) {
ret = false;
}
}
return ret;
}
@Override
public boolean isCancelled() {
for (Future<Boolean> op : operands) {
if (!op.isCancelled()) {
return false;
}
}
return true;
}
@Override
public boolean isDone() {
for (Future<Boolean> op : operands) {
if (!op.isDone()) {
return false;
}
}
return true;
}
@Override
public Boolean get() throws InterruptedException, ExecutionException {
boolean ret = Boolean.TRUE;
for (Future<Boolean> op : operands) {
if (!op.get()) {
ret = Boolean.FALSE;
}
}
return ret;
}
@Override
public Boolean get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException,
TimeoutException {
boolean ret = Boolean.TRUE;
long nanos = unit.toNanos(timeout);
long lastTime = System.nanoTime();
for (Future<Boolean> op : operands) {
if (!op.get(nanos, TimeUnit.NANOSECONDS)) {
ret = Boolean.FALSE;
}
long now = System.nanoTime();
nanos -= now - lastTime;
lastTime = now;
}
return ret;
}
}
|
