1 /**
2 * Copyright 2008 Atlassian Pty Ltd
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package com.atlassian.util.concurrent;
18
19 import java.util.concurrent.TimeUnit;
20 import java.util.concurrent.TimeoutException;
21 import java.util.concurrent.locks.Condition;
22
23 import net.jcip.annotations.Immutable;
24
25 /**
26 * Used to calculate elapsed time for timeouts from when it is created when
27 * successively calling blocking methods. Always converts to nanoseconds.
28 * <p>
29 * Usage:
30 *
31 * <pre>
32 * Timeout timeout = Timeout.getNanosTimeout(1, TimeUnit.SECONDS);
33 * String str = futureString.get(timeout.getTime(), timeout.getUnit());
34 * Integer num = futureInt.get(timeout.getTime(), timeout.getUnit());
35 * </pre>
36 *
37 * where if the first call takes quarter of a second, the second call is passed
38 * the equivalent of three-quarters of a second.
39 */
40 @Immutable
41 public class Timeout {
42
43 private static final TimeSupplier NANO_SUPPLIER = new TimeSupplier() {
44 public long currentTime() {
45 return System.nanoTime();
46 };
47
48 public TimeUnit precision() {
49 return TimeUnit.NANOSECONDS;
50 };
51 };
52
53 private static final TimeSupplier MILLIS_SUPPLIER = new TimeSupplier() {
54 public long currentTime() {
55 return System.currentTimeMillis();
56 };
57
58 public TimeUnit precision() {
59 return TimeUnit.MILLISECONDS;
60 };
61 };
62
63 /**
64 * Get a {@link Timeout} that uses nanosecond precision. The accuracy will
65 * depend on the accuracy of {@link System#nanoTime()}.
66 *
67 * @param time the maximum time to wait for the lock
68 * @param unit the time unit of the <tt>time</tt> argument.
69 * @return timeout with {@link TimeUnit#NANOSECONDS} precision.
70 */
71 public static Timeout getNanosTimeout(final long time, final TimeUnit unit) {
72 return new Timeout(time, unit, NANO_SUPPLIER);
73 }
74
75 /**
76 * Get a {@link Timeout} that uses nanosecond precision. The accuracy will
77 * depend on the accuracy of {@link System#nanoTime()}.
78 *
79 * @param time the maximum time to wait for the lock
80 * @param unit the time unit of the <tt>time</tt> argument.
81 * @return timeout with {@link TimeUnit#NANOSECONDS} precision.
82 */
83 public static Timeout getMillisTimeout(final long time, final TimeUnit unit) {
84 return new Timeout(time, unit, MILLIS_SUPPLIER);
85 }
86
87 private final long created;
88 private final long time;
89 private final TimeSupplier supplier;
90
91 Timeout(final long time, final TimeUnit unit, final TimeSupplier supplier) {
92 created = supplier.currentTime();
93 this.supplier = supplier;
94 this.time = this.supplier.precision().convert(time, unit);
95 }
96
97 public long getTime() {
98 return (created + time) - supplier.currentTime();
99 }
100
101 public TimeUnit getUnit() {
102 return supplier.precision();
103 }
104
105 /**
106 * Has this timeout expired
107 *
108 * @return
109 */
110 public boolean isExpired() {
111 return getTime() <= 0;
112 }
113
114 //
115 // util
116 //
117
118 void await(final Awaitable waitable) throws TimeoutException, InterruptedException {
119 if (!waitable.await(getTime(), getUnit())) {
120 throw new TimedOutException(this);
121 }
122 }
123
124 // TODO unused, retire?
125 // /CLOVER:OFF
126 void await(final Condition condition) throws TimeoutException, InterruptedException {
127 if (!condition.await(getTime(), getUnit())) {
128 throw new TimedOutException(this);
129 }
130 }
131
132 // /CLOVER:ON
133
134 /**
135 * Supply time and precision to a {@link Timeout}.
136 */
137 interface TimeSupplier {
138 long currentTime();
139
140 TimeUnit precision();
141 }
142 }