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 |
*/ |
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. 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>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) { |
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 |
} |