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Comparing jsr166/src/main/java/util/concurrent/TimeUnit.java (file contents):
Revision 1.21 by dl, Mon Feb 9 00:23:55 2004 UTC vs.
Revision 1.22 by dl, Thu Dec 30 13:04:46 2004 UTC

#	Line 1 | Line 1
1		/*
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
5	<	*/
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
5	>	*/
6
7		package java.util.concurrent;
8
9		/**
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.
16	<	*
17	<	* <p>A <tt>TimeUnit</tt> is mainly used to inform time-based methods
18	<	* how a given timing parameter should be interpreted. For example,
19	<	* the following code will timeout in 50 milliseconds if the {@link
20	<	* java.util.concurrent.locks.Lock lock} is not available:
21	<	*
22	<	* <pre>  Lock lock = ...;
23	<	*  if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ...
24	<	* </pre>
25	<	* while this code will timeout in 50 seconds:
26	<	* <pre>
27	<	*  Lock lock = ...;
28	<	*  if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ...
29	<	* </pre>
30	<	*
31	<	* Note however, that there is no guarantee that a particular timeout
32	<	* implementation will be able to notice the passage of time at the
33	<	* same granularity as the given <tt>TimeUnit</tt>.
34	<	*
35	<	* @since 1.5
36	<	* @author Doug Lea
37	<	*/
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
16	>	* one-billionth of a second, a microsecond is one-millionth of a
17	>	* second, a millisecond is one-thousandth of a second, a minute is
18	>	* sixty seconds, an hour is sixty minutes, and a day is twenty four
19	>	* hours.
20	>	*
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:
25	>	*
26	>	* <pre>  Lock lock = ...;
27	>	*  if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ...
28	>	* </pre>
29	>	* while this code will timeout in 50 seconds:
30	>	* <pre>
31	>	*  Lock lock = ...;
32	>	*  if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ...
33	>	* </pre>
34	>	*
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>.
38	>	*
39	>	* @since 1.5
40	>	* @author Doug Lea
41	>	*/
42		public enum TimeUnit {
43	<	NANOSECONDS(0), MICROSECONDS(1), MILLISECONDS(2), SECONDS(3);
44	<
45	<	/** the index of this unit */
46	<	private final int index;
47	<
48	<	/** Internal constructor */
49	<	TimeUnit(int index) {
50	<	this.index = index;
51	<	}
52	<
53	<	/** Lookup table for conversion factors */
54	<	private static final int[] multipliers = {
55	<	1,
56	<	1000,
57	<	1000 * 1000,
58	<	1000 * 1000 * 1000
59	<	};
60	<
61	<	/**
62	<	* Lookup table to check saturation.  Note that because we are
63	<	* dividing these down, we don't have to deal with asymmetry of
64	<	* MIN/MAX values.
65	<	*/
66	<	private static final long[] overflows = {
67	<	0, // unused
68	<	Long.MAX_VALUE / 1000,
69	<	Long.MAX_VALUE / (1000 * 1000),
70	<	Long.MAX_VALUE / (1000 * 1000 * 1000)
71	<	};
72	<
73	<	/**
74	<	* Perform conversion based on given delta representing the
75	<	* difference between units
76	<	* @param delta the difference in index values of source and target units
77	<	* @param duration the duration
78	<	* @return converted duration or saturated value
79	<	*/
80	<	private static long doConvert(int delta, long duration) {
81	<	if (delta == 0)
82	<	return duration;
83	<	if (delta < 0)
84	<	return duration / multipliers[-delta];
85	<	if (duration > overflows[delta])
86	<	return Long.MAX_VALUE;
87	<	if (duration < -overflows[delta])
88	<	return Long.MIN_VALUE;
89	<	return duration * multipliers[delta];
90	<	}
91	<
92	<	/**
93	<	* Convert the given time duration in the given unit to this
94	<	* unit.  Conversions from finer to coarser granularities
95	<	* truncate, so lose precision. For example converting
96	<	* <tt>999</tt> milliseconds to seconds results in
97	<	* <tt>0</tt>. Conversions from coarser to finer granularities
98	<	* with arguments that would numerically overflow saturate to
99	<	* <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt>
100	<	* if positive.
101	<	*
102	<	* @param duration the time duration in the given <tt>unit</tt>
103	<	* @param unit the unit of the <tt>duration</tt> argument
104	<	* @return the converted duration in this unit,
105	<	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
106	<	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
107	<	*/
108	<	public long convert(long duration, TimeUnit unit) {
109	<	return doConvert(unit.index - index, duration);
110	<	}
111	<
112	<	/**
113	<	* Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>.
114	<	* @param duration the duration
115	<	* @return the converted duration,
116	<	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
117	<	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
118	<	* @see #convert
119	<	*/
120	<	public long toNanos(long duration) {
121	<	return doConvert(index, duration);
122	<	}
123	<
124	<	/**
125	<	* Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>.
126	<	* @param duration the duration
127	<	* @return the converted duration,
128	<	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
129	<	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
130	<	* @see #convert
131	<	*/
132	<	public long toMicros(long duration) {
133	<	return doConvert(index - MICROSECONDS.index, duration);
134	<	}
135	<
136	<	/**
137	<	* Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>.
138	<	* @param duration the duration
139	<	* @return the converted duration,
140	<	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
141	<	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
142	<	* @see #convert
143	<	*/
144	<	public long toMillis(long duration) {
145	<	return doConvert(index - MILLISECONDS.index, duration);
146	<	}
147	<
148	<	/**
149	<	* Equivalent to <tt>SECONDS.convert(duration, this)</tt>.
150	<	* @param duration the duration
151	<	* @return the converted duration.
152	<	* @see #convert
153	<	*/
154	<	public long toSeconds(long duration) {
155	<	return doConvert(index - SECONDS.index, duration);
156	<	}
157	<
158	<
159	<	/**
160	<	* Utility method to compute the excess-nanosecond argument to
161	<	* wait, sleep, join.
162	<	*/
163	<	private int excessNanos(long time, long ms) {
164	<	if (this == NANOSECONDS)
165	<	return (int) (time  - (ms * 1000 * 1000));
166	<	if (this == MICROSECONDS)
167	<	return (int) ((time * 1000) - (ms * 1000 * 1000));
168	<	return 0;
169	<	}
170	<
171	<	/**
172	<	* Perform a timed <tt>Object.wait</tt> using this time unit.
173	<	* This is a convenience method that converts timeout arguments
174	<	* into the form required by the <tt>Object.wait</tt> method.
175	<	*
176	<	* <p>For example, you could implement a blocking <tt>poll</tt>
177	<	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
178	<	* using:
179	<	*
180	<	* <pre>  public synchronized  Object poll(long timeout, TimeUnit unit) throws InterruptedException {
181	<	*    while (empty) {
182	<	*      unit.timedWait(this, timeout);
183	<	*      ...
184	<	*    }
185	<	*  }</pre>
186	<	*
187	<	* @param obj the object to wait on
188	<	* @param timeout the maximum time to wait.
189	<	* @throws InterruptedException if interrupted while waiting.
190	<	* @see Object#wait(long, int)
191	<	*/
192	<	public void timedWait(Object obj, long timeout)
193	<	throws InterruptedException {
194	<	if (timeout > 0) {
195	<	long ms = toMillis(timeout);
196	<	int ns = excessNanos(timeout, ms);
197	<	obj.wait(ms, ns);
198	<	}
199	<	}
200	<
201	<	/**
202	<	* Perform a timed <tt>Thread.join</tt> using this time unit.
203	<	* This is a convenience method that converts time arguments into the
204	<	* form required by the <tt>Thread.join</tt> method.
205	<	* @param thread the thread to wait for
206	<	* @param timeout the maximum time to wait
207	<	* @throws InterruptedException if interrupted while waiting.
208	<	* @see Thread#join(long, int)
209	<	*/
210	<	public void timedJoin(Thread thread, long timeout)
211	<	throws InterruptedException {
212	<	if (timeout > 0) {
213	<	long ms = toMillis(timeout);
214	<	int ns = excessNanos(timeout, ms);
215	<	thread.join(ms, ns);
216	<	}
217	<	}
218	<
219	<	/**
220	<	* Perform a <tt>Thread.sleep</tt> using this unit.
221	<	* This is a convenience method that converts time arguments into the
222	<	* form required by the <tt>Thread.sleep</tt> method.
223	<	* @param timeout the minimum time to sleep
224	<	* @throws InterruptedException if interrupted while sleeping.
225	<	* @see Thread#sleep
226	<	*/
227	<	public void sleep(long timeout) throws InterruptedException {
228	<	if (timeout > 0) {
229	<	long ms = toMillis(timeout);
230	<	int ns = excessNanos(timeout, ms);
231	<	Thread.sleep(ms, ns);
232	<	}
233	<	}
43	>	NANOSECONDS (0) {
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)); }
53	>	},
54	>	MICROSECONDS (1) {
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)); }
64	>	},
65	>	MILLISECONDS (2) {
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; }
75	>	},
76	>	SECONDS (3) {
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; }
86	>	},
87	>	MINUTES (4) {
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; }
97	>	},
98	>	HOURS (5) {
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; }
108	>	},
109	>	DAYS (6) {
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; }
119	>	};
120	>
121	>	/**
122	>	* The index of this unit. This value is no longer used in this
123	>	* version of this class, but is retained for serialization
124	>	* compatibility with previous version.
125	>	*/
126	>	private final int index;
127	>
128	>	/** Internal constructor */
129	>	TimeUnit(int index) {
130	>	this.index = index;
131	>	}
132	>
133	>	// Handy constants for conversion methods
134	>	static final long C0 = 1;
135	>	static final long C1 = C0 * 1000;
136	>	static final long C2 = C1 * 1000;
137	>	static final long C3 = C2 * 1000;
138	>	static final long C4 = C3 * 60;
139	>	static final long C5 = C4 * 60;
140	>	static final long C6 = C5 * 24;
141	>
142	>	static final long MAX = Long.MAX_VALUE;
143	>
144	>	/**
145	>	* Scale d by m, checking for overflow.
146	>	* This has a short name to make above code more readable.
147	>	*/
148	>	static long x(long d, long m, long over) {
149	>	if (d >  over) return Long.MAX_VALUE;
150	>	if (d < -over) return Long.MIN_VALUE;
151	>	return d * m;
152	>	}
153	>
154	>	/**
155	>	* Convert the given time duration in the given unit to this
156	>	* unit.  Conversions from finer to coarser granularities
157	>	* truncate, so lose precision. For example converting
158	>	* <tt>999</tt> milliseconds to seconds results in
159	>	* <tt>0</tt>. Conversions from coarser to finer granularities
160	>	* with arguments that would numerically overflow saturate to
161	>	* <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt>
162	>	* if positive.
163	>	*
164	>	* @param duration the time duration in the given <tt>unit</tt>
165	>	* @param unit the unit of the <tt>duration</tt> argument
166	>	* @return the converted duration in this unit,
167	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
168	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
169	>	*/
170	>	public abstract long convert(long duration, TimeUnit unit);
171	>
172	>	/**
173	>	* Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>.
174	>	* @param duration the duration
175	>	* @return the converted duration,
176	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
177	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
178	>	* @see #convert
179	>	*/
180	>	public abstract long toNanos(long duration);
181	>
182	>	/**
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.
188	>	* @see #convert
189	>	*/
190	>	public abstract long toMicros(long duration);
191	>
192	>	/**
193	>	* Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>.
194	>	* @param duration the duration
195	>	* @return the converted duration,
196	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
197	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
198	>	* @see #convert
199	>	*/
200	>	public abstract long toMillis(long duration);
201	>
202	>	/**
203	>	* Equivalent to <tt>SECONDS.convert(duration, this)</tt>.
204	>	* @param duration the duration
205	>	* @return the converted duration.
206	>	* @see #convert
207	>	*/
208	>	public abstract long toSeconds(long duration);
209	>
210	>	/**
211	>	* Equivalent to <tt>MINUTES.convert(duration, this)</tt>.
212	>	* @param duration the duration
213	>	* @return the converted duration.
214	>	* @see #convert
215	>	*/
216	>	public abstract long toMinutes(long duration);
217	>
218	>	/**
219	>	* Equivalent to <tt>HOURS.convert(duration, this)</tt>.
220	>	* @param duration the duration
221	>	* @return the converted duration.
222	>	* @see #convert
223	>	*/
224	>	public abstract long toHours(long duration);
225	>
226	>	/**
227	>	* Equivalent to <tt>DAYS.convert(duration, this)</tt>.
228	>	* @param duration the duration
229	>	* @return the converted duration.
230	>	* @see #convert
231	>	*/
232	>	public abstract long toDays(long duration);
233	>
234	>	/**
235	>	* Utility to compute the excess-nanosecond argument to wait,
236	>	* sleep, join.
237	>	* @param d the duration
238	>	* @param m the number of millisecondss
239	>	* @return the number of nanoseconds
240	>	*/
241	>	abstract int excessNanos(long d, long m);
242	>
243	>	/**
244	>	* Perform a timed <tt>Object.wait</tt> using this time unit.
245	>	* This is a convenience method that converts timeout arguments
246	>	* into the form required by the <tt>Object.wait</tt> method.
247	>	*
248	>	* <p>For example, you could implement a blocking <tt>poll</tt>
249	>	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
250	>	* using:
251	>	*
252	>	* <pre>  public synchronized  Object poll(long timeout, TimeUnit unit) throws InterruptedException {
253	>	*    while (empty) {
254	>	*      unit.timedWait(this, timeout);
255	>	*      ...
256	>	*    }
257	>	*  }</pre>
258	>	*
259	>	* @param obj the object to wait on
260	>	* @param timeout the maximum time to wait.
261	>	* @throws InterruptedException if interrupted while waiting.
262	>	* @see Object#wait(long, int)
263	>	*/
264	>	public void timedWait(Object obj, long timeout)
265	>	throws InterruptedException {
266	>	if (timeout > 0) {
267	>	long ms = toMillis(timeout);
268	>	int ns = excessNanos(timeout, ms);
269	>	obj.wait(ms, ns);
270	>	}
271	>	}
272	>
273	>	/**
274	>	* Perform a timed <tt>Thread.join</tt> using this time unit.
275	>	* This is a convenience method that converts time arguments into the
276	>	* form required by the <tt>Thread.join</tt> method.
277	>	* @param thread the thread to wait for
278	>	* @param timeout the maximum time to wait
279	>	* @throws InterruptedException if interrupted while waiting.
280	>	* @see Thread#join(long, int)
281	>	*/
282	>	public void timedJoin(Thread thread, long timeout)
283	>	throws InterruptedException {
284	>	if (timeout > 0) {
285	>	long ms = toMillis(timeout);
286	>	int ns = excessNanos(timeout, ms);
287	>	thread.join(ms, ns);
288	>	}
289	>	}
290	>
291	>	/**
292	>	* Perform a <tt>Thread.sleep</tt> using this unit.
293	>	* This is a convenience method that converts time arguments into the
294	>	* form required by the <tt>Thread.sleep</tt> method.
295	>	* @param timeout the minimum time to sleep
296	>	* @throws InterruptedException if interrupted while sleeping.
297	>	* @see Thread#sleep
298	>	*/
299	>	public void sleep(long timeout) throws InterruptedException {
300	>	if (timeout > 0) {
301	>	long ms = toMillis(timeout);
302	>	int ns = excessNanos(timeout, ms);
303	>	Thread.sleep(ms, ns);
304	>	}
305	>	}
306
307		}

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