2 * Written by Doug Lea with assistance from members of JCP JSR-166
3 * Expert Group and released to the public domain, as explained at
4 * http://creativecommons.org/licenses/publicdomain
7 package java.util.concurrent;
10 * A <tt>TimeUnit</tt> represents time durations at a given unit of
11 * granularity and provides utility methods to convert across units,
12 * and to perform timing and delay operations in these units. A
13 * <tt>TimeUnit</tt> does not maintain time information, but only
14 * helps organize and use time representations that may be maintained
15 * separately across various contexts. A nanosecond is defined as one
16 * thousandth of a microsecond, a microsecond as one thousandth of a
17 * millisecond, a millisecond as one thousandth of a second, a minute
18 * as sixty seconds, an hour as sixty minutes, and a day as twenty four
21 * <p>A <tt>TimeUnit</tt> is mainly used to inform time-based methods
22 * how a given timing parameter should be interpreted. For example,
23 * the following code will timeout in 50 milliseconds if the {@link
24 * java.util.concurrent.locks.Lock lock} is not available:
26 * <pre> Lock lock = ...;
27 * if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ...
29 * while this code will timeout in 50 seconds:
32 * if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ...
35 * Note however, that there is no guarantee that a particular timeout
36 * implementation will be able to notice the passage of time at the
37 * same granularity as the given <tt>TimeUnit</tt>.
42 public enum TimeUnit {
44 public long toNanos(long d) { return d; }
45 public long toMicros(long d) { return d/(C1/C0); }
46 public long toMillis(long d) { return d/(C2/C0); }
47 public long toSeconds(long d) { return d/(C3/C0); }
48 public long toMinutes(long d) { return d/(C4/C0); }
49 public long toHours(long d) { return d/(C5/C0); }
50 public long toDays(long d) { return d/(C6/C0); }
51 public long convert(long d, TimeUnit u) { return u.toNanos(d); }
52 int excessNanos(long d, long m) { return (int)(d - (m*C2)); }
55 public long toNanos(long d) { return x(d, C1/C0, MAX/(C1/C0)); }
56 public long toMicros(long d) { return d; }
57 public long toMillis(long d) { return d/(C2/C1); }
58 public long toSeconds(long d) { return d/(C3/C1); }
59 public long toMinutes(long d) { return d/(C4/C1); }
60 public long toHours(long d) { return d/(C5/C1); }
61 public long toDays(long d) { return d/(C6/C1); }
62 public long convert(long d, TimeUnit u) { return u.toMicros(d); }
63 int excessNanos(long d, long m) { return (int)((d*C1) - (m*C2)); }
66 public long toNanos(long d) { return x(d, C2/C0, MAX/(C2/C0)); }
67 public long toMicros(long d) { return x(d, C2/C1, MAX/(C2/C1)); }
68 public long toMillis(long d) { return d; }
69 public long toSeconds(long d) { return d/(C3/C2); }
70 public long toMinutes(long d) { return d/(C4/C2); }
71 public long toHours(long d) { return d/(C5/C2); }
72 public long toDays(long d) { return d/(C6/C2); }
73 public long convert(long d, TimeUnit u) { return u.toMillis(d); }
74 int excessNanos(long d, long m) { return 0; }
77 public long toNanos(long d) { return x(d, C3/C0, MAX/(C3/C0)); }
78 public long toMicros(long d) { return x(d, C3/C1, MAX/(C3/C1)); }
79 public long toMillis(long d) { return x(d, C3/C2, MAX/(C3/C2)); }
80 public long toSeconds(long d) { return d; }
81 public long toMinutes(long d) { return d/(C4/C3); }
82 public long toHours(long d) { return d/(C5/C3); }
83 public long toDays(long d) { return d/(C6/C3); }
84 public long convert(long d, TimeUnit u) { return u.toSeconds(d); }
85 int excessNanos(long d, long m) { return 0; }
88 public long toNanos(long d) { return x(d, C4/C0, MAX/(C4/C0)); }
89 public long toMicros(long d) { return x(d, C4/C1, MAX/(C4/C1)); }
90 public long toMillis(long d) { return x(d, C4/C2, MAX/(C4/C2)); }
91 public long toSeconds(long d) { return x(d, C4/C3, MAX/(C4/C3)); }
92 public long toMinutes(long d) { return d; }
93 public long toHours(long d) { return d/(C5/C4); }
94 public long toDays(long d) { return d/(C6/C4); }
95 public long convert(long d, TimeUnit u) { return u.toMinutes(d); }
96 int excessNanos(long d, long m) { return 0; }
99 public long toNanos(long d) { return x(d, C5/C0, MAX/(C5/C0)); }
100 public long toMicros(long d) { return x(d, C5/C1, MAX/(C5/C1)); }
101 public long toMillis(long d) { return x(d, C5/C2, MAX/(C5/C2)); }
102 public long toSeconds(long d) { return x(d, C5/C3, MAX/(C5/C3)); }
103 public long toMinutes(long d) { return x(d, C5/C4, MAX/(C5/C4)); }
104 public long toHours(long d) { return d; }
105 public long toDays(long d) { return d/(C6/C5); }
106 public long convert(long d, TimeUnit u) { return u.toHours(d); }
107 int excessNanos(long d, long m) { return 0; }
110 public long toNanos(long d) { return x(d, C6/C0, MAX/(C6/C0)); }
111 public long toMicros(long d) { return x(d, C6/C1, MAX/(C6/C1)); }
112 public long toMillis(long d) { return x(d, C6/C2, MAX/(C6/C2)); }
113 public long toSeconds(long d) { return x(d, C6/C3, MAX/(C6/C3)); }
114 public long toMinutes(long d) { return x(d, C6/C4, MAX/(C6/C4)); }
115 public long toHours(long d) { return x(d, C6/C5, MAX/(C6/C5)); }
116 public long toDays(long d) { return d; }
117 public long convert(long d, TimeUnit u) { return u.toDays(d); }
118 int excessNanos(long d, long m) { return 0; }
121 // Handy constants for conversion methods
122 static final long C0 = 1L;
123 static final long C1 = C0 * 1000L;
124 static final long C2 = C1 * 1000L;
125 static final long C3 = C2 * 1000L;
126 static final long C4 = C3 * 60L;
127 static final long C5 = C4 * 60L;
128 static final long C6 = C5 * 24L;
130 static final long MAX = Long.MAX_VALUE;
133 * Scale d by m, checking for overflow.
134 * This has a short name to make above code more readable.
136 static long x(long d, long m, long over) {
137 if (d > over) return Long.MAX_VALUE;
138 if (d < -over) return Long.MIN_VALUE;
142 // To maintain full signature compatibility with 1.5, and to improve the
143 // clarity of the generated javadoc (see 6287639: Abstract methods in
144 // enum classes should not be listed as abstract), method convert
145 // etc. are not declared abstract but otherwise act as abstract methods.
148 * Convert the given time duration in the given unit to this
149 * unit. Conversions from finer to coarser granularities
150 * truncate, so lose precision. For example converting
151 * <tt>999</tt> milliseconds to seconds results in
152 * <tt>0</tt>. Conversions from coarser to finer granularities
153 * with arguments that would numerically overflow saturate to
154 * <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt>
157 * <p>For example, to convert 10 minutes to milliseconds, use:
158 * <tt>TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)</tt>
160 * @param sourceDuration the time duration in the given <tt>sourceUnit</tt>
161 * @param sourceUnit the unit of the <tt>sourceDuration</tt> argument
162 * @return the converted duration in this unit,
163 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
164 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
166 public long convert(long sourceDuration, TimeUnit sourceUnit) {
167 throw new AbstractMethodError();
171 * Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>.
172 * @param duration the duration
173 * @return the converted duration,
174 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
175 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
178 public long toNanos(long duration) {
179 throw new AbstractMethodError();
183 * Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>.
184 * @param duration the duration
185 * @return the converted duration,
186 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
187 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
190 public long toMicros(long duration) {
191 throw new AbstractMethodError();
195 * Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>.
196 * @param duration the duration
197 * @return the converted duration,
198 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
199 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
202 public long toMillis(long duration) {
203 throw new AbstractMethodError();
207 * Equivalent to <tt>SECONDS.convert(duration, this)</tt>.
208 * @param duration the duration
209 * @return the converted duration,
210 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
211 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
214 public long toSeconds(long duration) {
215 throw new AbstractMethodError();
219 * Equivalent to <tt>MINUTES.convert(duration, this)</tt>.
220 * @param duration the duration
221 * @return the converted duration,
222 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
223 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
227 public long toMinutes(long duration) {
228 throw new AbstractMethodError();
232 * Equivalent to <tt>HOURS.convert(duration, this)</tt>.
233 * @param duration the duration
234 * @return the converted duration,
235 * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
236 * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
240 public long toHours(long duration) {
241 throw new AbstractMethodError();
245 * Equivalent to <tt>DAYS.convert(duration, this)</tt>.
246 * @param duration the duration
247 * @return the converted duration
251 public long toDays(long duration) {
252 throw new AbstractMethodError();
256 * Utility to compute the excess-nanosecond argument to wait,
258 * @param d the duration
259 * @param m the number of milliseconds
260 * @return the number of nanoseconds
262 abstract int excessNanos(long d, long m);
265 * Performs a timed <tt>Object.wait</tt> using this time unit.
266 * This is a convenience method that converts timeout arguments
267 * into the form required by the <tt>Object.wait</tt> method.
269 * <p>For example, you could implement a blocking <tt>poll</tt>
270 * method (see {@link BlockingQueue#poll BlockingQueue.poll})
273 * <pre> public synchronized Object poll(long timeout, TimeUnit unit) throws InterruptedException {
275 * unit.timedWait(this, timeout);
280 * @param obj the object to wait on
281 * @param timeout the maximum time to wait. If less than
282 * or equal to zero, do not wait at all.
283 * @throws InterruptedException if interrupted while waiting.
284 * @see Object#wait(long, int)
286 public void timedWait(Object obj, long timeout)
287 throws InterruptedException {
289 long ms = toMillis(timeout);
290 int ns = excessNanos(timeout, ms);
296 * Performs a timed <tt>Thread.join</tt> using this time unit.
297 * This is a convenience method that converts time arguments into the
298 * form required by the <tt>Thread.join</tt> method.
299 * @param thread the thread to wait for
300 * @param timeout the maximum time to wait. If less than
301 * or equal to zero, do not wait at all.
302 * @throws InterruptedException if interrupted while waiting.
303 * @see Thread#join(long, int)
305 public void timedJoin(Thread thread, long timeout)
306 throws InterruptedException {
308 long ms = toMillis(timeout);
309 int ns = excessNanos(timeout, ms);
315 * Performs a <tt>Thread.sleep</tt> using this unit.
316 * This is a convenience method that converts time arguments into the
317 * form required by the <tt>Thread.sleep</tt> method.
318 * @param timeout the minimum time to sleep. If less than
319 * or equal to zero, do not sleep at all.
320 * @throws InterruptedException if interrupted while sleeping.
323 public void sleep(long timeout) throws InterruptedException {
325 long ms = toMillis(timeout);
326 int ns = excessNanos(timeout, ms);
327 Thread.sleep(ms, ns);