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Comparing jsr166/src/main/java/util/concurrent/TimeUnit.java (file contents):
Revision 1.10 by dl, Sat Aug 30 14:52:52 2003 UTC vs.
Revision 1.27 by dl, Tue Mar 8 12:27:11 2005 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. Use, modify, and
4	<	* redistribute this code in any way without acknowledgement.
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.
13	<	* <tt>TimeUnit</tt> is a &quot;featherweight&quot; class.
14	<	* It does not maintain time information, but only helps organize and
15	<	* use time representations that may be maintained separately across
16	<	* various contexts.
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
19	>	* hours.
20		*
21	<	* <p>The <tt>TimeUnit</tt> class cannot be directly instantiated.
22	<	* Use the {@link #SECONDS}, {@link #MILLISECONDS}, {@link #MICROSECONDS},
23	<	* and {@link #NANOSECONDS} static instances that provide predefined
24	<	* units of precision. If you use these frequently, consider
22	<	* statically importing this class.
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		*
24	–	* <p>A <tt>TimeUnit</tt> is mainly used to inform blocking methods which
25	–	* can timeout, how the timeout parameter should be interpreted. For example,
26	–	* the following code will timeout in 50 milliseconds if the {@link java.util.concurrent.locks.Lock lock}
27	–	* is not available:
26		* <pre>  Lock lock = ...;
27		*  if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ...
28		* </pre>
#	Line 33 | Line 31 | package java.util.concurrent;
31		*  Lock lock = ...;
32		*  if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ...
33		* </pre>
34	<	* Note however, that there is no guarantee that a particular lock, in this
35	<	* case, will be able to notice the passage of time at the same granularity
36	<	* as the given <tt>TimeUnit</tt>.
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
41	–	* @spec JSR-166
42	–	* @revised $Date$
43	–	* @editor $Author$
40		* @author Doug Lea
41		*/
42	<	public final class TimeUnit implements java.io.Serializable {
43	<
42	>	public enum TimeUnit {
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 = 1L;
135	>	static final long C1 = C0 * 1000L;
136	>	static final long C2 = C1 * 1000L;
137	>	static final long C3 = C2 * 1000L;
138	>	static final long C4 = C3 * 60L;
139	>	static final long C5 = C4 * 60L;
140	>	static final long C6 = C5 * 24L;
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 the
156	<	* current unit.  Conversions from finer to coarser granulaties
157	<	* truncate, so lose precision. Conversions from coarser to finer
158	<	* granularities with arguments that would numerically overflow
159	<	* saturate to <tt>Long.MIN_VALUE</tt> if negative or
160	<	* <tt>Long>MAX_VALUE</tt> if positive.
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 the current unit,
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.
168	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
169		*/
170	<	public long convert(long duration, TimeUnit unit) {
171	<	if (unit == this)
64	<	return duration;
65	<	else if (index > unit.index)
66	<	return duration / multipliers[index - unit.index];
67	<	else {
68	<	int i = unit.index - index;
69	<	if (duration > overflows[i])
70	<	return Long.MAX_VALUE;
71	<	if (duration < -overflows[i])
72	<	return Long.MIN_VALUE;
73	<	return duration * multipliers[i];
74	<	}
75	<	}
76	<
170	>	public abstract long convert(long duration, TimeUnit unit);
171	>
172		/**
173	<	* Equivalent to <code>NANOSECONDS.convert(duration, this)</code>.
173	>	* Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>.
174		* @param duration the duration
175	<	* @return the converted 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	<	**/
179	<	public long toNanos(long duration) {
180	<	if (index == NS)
181	<	return duration;
182	<	if (duration > overflows[index])
183	<	return Long.MAX_VALUE;
184	<	if (duration < -overflows[index])
185	<	return Long.MIN_VALUE;
186	<	return duration * multipliers[index];
187	<	}
188	<
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	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
207	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
208	>	* @see #convert
209	>	*/
210	>	public abstract long toSeconds(long duration);
211	>
212	>	/**
213	>	* Equivalent to <tt>MINUTES.convert(duration, this)</tt>.
214	>	* @param duration the duration
215	>	* @return the converted duration,
216	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
217	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
218	>	* @see #convert
219	>	*/
220	>	public abstract long toMinutes(long duration);
221	>
222	>	/**
223	>	* Equivalent to <tt>HOURS.convert(duration, this)</tt>.
224	>	* @param duration the duration
225	>	* @return the converted duration,
226	>	* or <tt>Long.MIN_VALUE</tt> if conversion would negatively
227	>	* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
228	>	* @see #convert
229	>	*/
230	>	public abstract long toHours(long duration);
231	>
232	>	/**
233	>	* Equivalent to <tt>DAYS.convert(duration, this)</tt>.
234	>	* @param duration the duration
235	>	* @return the converted duration
236	>	* @see #convert
237	>	*/
238	>	public abstract long toDays(long duration);
239	>
240	>	/**
241	>	* Utility to compute the excess-nanosecond argument to wait,
242	>	* sleep, join.
243	>	* @param d the duration
244	>	* @param m the number of milliseconds
245	>	* @return the number of nanoseconds
246	>	*/
247	>	abstract int excessNanos(long d, long m);
248	>
249		/**
250	<	* Perform a timed <tt>Object.wait</tt> using the current time unit.
251	<	* This is a convenience method that converts timeout arguments into the
252	<	* form required by the <tt>Object.wait</tt> method.
253	<	* <p>For example, you could implement a blocking <tt>poll</tt> method (see
254	<	* {@link BlockingQueue#poll BlockingQueue.poll} using:
250	>	* Perform a timed <tt>Object.wait</tt> using this time unit.
251	>	* This is a convenience method that converts timeout arguments
252	>	* into the form required by the <tt>Object.wait</tt> method.
253	>	*
254	>	* <p>For example, you could implement a blocking <tt>poll</tt>
255	>	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
256	>	* using:
257	>	*
258		* <pre>  public synchronized  Object poll(long timeout, TimeUnit unit) throws InterruptedException {
259		*    while (empty) {
260		*      unit.timedWait(this, timeout);
261		*      ...
262		*    }
263		*  }</pre>
264	+	*
265		* @param obj the object to wait on
266	<	* @param timeout the maximum time to wait.
266	>	* @param timeout the maximum time to wait.
267		* @throws InterruptedException if interrupted while waiting.
268		* @see Object#wait(long, int)
269		*/
270		public void timedWait(Object obj, long timeout)
271	<	throws InterruptedException {
271	>	throws InterruptedException {
272		if (timeout > 0) {
273	<	long ms = MILLISECONDS.convert(timeout, this);
273	>	long ms = toMillis(timeout);
274		int ns = excessNanos(timeout, ms);
275		obj.wait(ms, ns);
276		}
277		}
278	<
278	>
279		/**
280	<	* Perform a timed <tt>Thread.join</tt> using the current time unit.
280	>	* Perform a timed <tt>Thread.join</tt> using this time unit.
281		* This is a convenience method that converts time arguments into the
282		* form required by the <tt>Thread.join</tt> method.
283		* @param thread the thread to wait for
#	Line 127 | Line 286 | public final class TimeUnit implements j
286		* @see Thread#join(long, int)
287		*/
288		public void timedJoin(Thread thread, long timeout)
289	<	throws InterruptedException {
289	>	throws InterruptedException {
290		if (timeout > 0) {
291	<	long ms = MILLISECONDS.convert(timeout, this);
291	>	long ms = toMillis(timeout);
292		int ns = excessNanos(timeout, ms);
293		thread.join(ms, ns);
294		}
295		}
296	<
296	>
297		/**
298	<	* Perform a <tt>Thread.sleep</tt> using the current time unit.
298	>	* Perform a <tt>Thread.sleep</tt> using this unit.
299		* This is a convenience method that converts time arguments into the
300		* form required by the <tt>Thread.sleep</tt> method.
301		* @param timeout the minimum time to sleep
#	Line 145 | Line 304 | public final class TimeUnit implements j
304		*/
305		public void sleep(long timeout) throws InterruptedException {
306		if (timeout > 0) {
307	<	long ms = MILLISECONDS.convert(timeout, this);
307	>	long ms = toMillis(timeout);
308		int ns = excessNanos(timeout, ms);
309		Thread.sleep(ms, ns);
310		}
311		}
312	<
154	<	/**
155	<	* Return the common name for this unit.
156	<	*/
157	<	public String toString() {
158	<	return unitName;
159	<	}
160	<
161	<	private final String unitName;
162	<
163	<	/* ordered indices for each time unit */
164	<	private static final int NS = 0;
165	<	private static final int US = 1;
166	<	private static final int MS = 2;
167	<	private static final int S  = 3;
168	<
169	<	/** quick lookup table for conversion factors */
170	<	static final int[] multipliers = { 1,
171	<	1000,
172	<	1000*1000,
173	<	1000*1000*1000 };
174	<
175	<	/** lookup table to check saturation */
176	<	static final long[] overflows = {
177	<	// Note that because we are dividing these down anyway,
178	<	// we don't have to deal with asymmetry of MIN/MAX values.
179	<	0, // unused
180	<	Long.MAX_VALUE / 1000,
181	<	Long.MAX_VALUE / (1000 * 1000),
182	<	Long.MAX_VALUE / (1000 * 1000 * 1000) };
183	<
184	<	/** the index of this unit */
185	<	int index;
186	<
187	<	/** private constructor */
188	<	TimeUnit(int index, String name) {
189	<	this.index = index;
190	<	this.unitName = name;
191	<	}
192	<
193	<	/**
194	<	* Utility method to compute the excess-nanosecond argument to
195	<	* wait, sleep, join. The results may overflow, so public methods
196	<	* invoking this should document possible overflow unless
197	<	* overflow is known not to be possible for the given arguments.
198	<	*/
199	<	private int excessNanos(long time, long ms) {
200	<	if (index == NS)
201	<	return (int) (time  - (ms * multipliers[MS-NS]));
202	<	else if (index == US)
203	<	return (int) ((time * multipliers[US-NS]) - (ms * multipliers[MS-NS]));
204	<	else
205	<	return 0;
206	<	}
207	<
208	<	/** Unit for one-second granularities. */
209	<	public static final TimeUnit SECONDS = new TimeUnit(S, "seconds");
210	<
211	<	/** Unit for one-millisecond granularities. */
212	<	public static final TimeUnit MILLISECONDS = new TimeUnit(MS, "milliseconds");
213	<
214	<	/** Unit for one-microsecond granularities. */
215	<	public static final TimeUnit MICROSECONDS = new TimeUnit(US, "microseconds");
216	<
217	<	/** Unit for one-nanosecond granularities. */
218	<	public static final TimeUnit NANOSECONDS = new TimeUnit(NS, "nanoseconds");
219	<
312	>
313		}

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