util/concurrent/TimeUnit.java

/*
  * Written by Doug Lea with assistance from members of JCP JSR-166
  * Expert Group and released to the public domain, as explained at
  * http://creativecommons.org/licenses/publicdomain
  */

package java.util.concurrent;

/**
  * A <tt>TimeUnit</tt> represents time durations at a given unit of
  * granularity and provides utility methods to convert across units,
  * and to perform timing and delay operations in these units.  A
  * <tt>TimeUnit</tt> does not maintain time information, but only
  * helps organize and use time representations that may be maintained
  * separately across various contexts.  A nanosecond is defined as one
  * thousandth of a microsecond, a microsecond as one thousandth of a
  * millisecond, a millisecond as one thousandth of a second, a minute
  * as sixty seconds, an hour as sixty minutes, and a day as twenty four
  * hours.
  *
  * <p>A <tt>TimeUnit</tt> is mainly used to inform time-based methods
  * how a given timing parameter should be interpreted. For example,
  * the following code will timeout in 50 milliseconds if the {@link
  * java.util.concurrent.locks.Lock lock} is not available:
  *
  * <pre>  Lock lock = ...;
  *  if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ...
  * </pre>
  * while this code will timeout in 50 seconds:
  * <pre>
  *  Lock lock = ...;
  *  if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ...
  * </pre>
  *
  * Note however, that there is no guarantee that a particular timeout
  * implementation will be able to notice the passage of time at the
  * same granularity as the given <tt>TimeUnit</tt>.
  *
  * @since 1.5
  * @author Doug Lea
  */
public enum TimeUnit {
     NANOSECONDS (0) {
         public long toNanos(long d)   { return d; }
         public long toMicros(long d)  { return d/(C1/C0); }
         public long toMillis(long d)  { return d/(C2/C0); }
         public long toSeconds(long d) { return d/(C3/C0); }
         public long toMinutes(long d) { return d/(C4/C0); }
         public long toHours(long d)   { return d/(C5/C0); }
         public long toDays(long d)    { return d/(C6/C0); }
         public long convert(long d, TimeUnit u) { return u.toNanos(d); }
         int excessNanos(long d, long m) { return (int)(d - (m*C2)); }
     },
     MICROSECONDS (1) {
         public long toNanos(long d)   { return x(d, C1/C0, MAX/(C1/C0)); }
         public long toMicros(long d)  { return d; }
         public long toMillis(long d)  { return d/(C2/C1); }
         public long toSeconds(long d) { return d/(C3/C1); }
         public long toMinutes(long d) { return d/(C4/C1); }
         public long toHours(long d)   { return d/(C5/C1); }
         public long toDays(long d)    { return d/(C6/C1); }
         public long convert(long d, TimeUnit u) { return u.toMicros(d); }
         int excessNanos(long d, long m) { return (int)((d*C1) - (m*C2)); }
     },
     MILLISECONDS (2) {
         public long toNanos(long d)   { return x(d, C2/C0, MAX/(C2/C0)); }
         public long toMicros(long d)  { return x(d, C2/C1, MAX/(C2/C1)); }
         public long toMillis(long d)  { return d; }
         public long toSeconds(long d) { return d/(C3/C2); }
         public long toMinutes(long d) { return d/(C4/C2); }
         public long toHours(long d)   { return d/(C5/C2); }
         public long toDays(long d)    { return d/(C6/C2); }
         public long convert(long d, TimeUnit u) { return u.toMillis(d); }
         int excessNanos(long d, long m) { return 0; }
     },
     SECONDS (3) {
         public long toNanos(long d)   { return x(d, C3/C0, MAX/(C3/C0)); }
         public long toMicros(long d)  { return x(d, C3/C1, MAX/(C3/C1)); }
         public long toMillis(long d)  { return x(d, C3/C2, MAX/(C3/C2)); }
         public long toSeconds(long d) { return d; }
         public long toMinutes(long d) { return d/(C4/C3); }
         public long toHours(long d)   { return d/(C5/C3); }
         public long toDays(long d)    { return d/(C6/C3); }
         public long convert(long d, TimeUnit u) { return u.toSeconds(d); }
         int excessNanos(long d, long m) { return 0; }
     },
     MINUTES (4) {
         public long toNanos(long d)   { return x(d, C4/C0, MAX/(C4/C0)); }
         public long toMicros(long d)  { return x(d, C4/C1, MAX/(C4/C1)); }
         public long toMillis(long d)  { return x(d, C4/C2, MAX/(C4/C2)); }
         public long toSeconds(long d) { return x(d, C4/C3, MAX/(C4/C3)); }
         public long toMinutes(long d) { return d; }
         public long toHours(long d)   { return d/(C5/C4); }
         public long toDays(long d)    { return d/(C6/C4); }
         public long convert(long d, TimeUnit u) { return u.toMinutes(d); }
         int excessNanos(long d, long m) { return 0; }
     },
     HOURS (5) {
         public long toNanos(long d)   { return x(d, C5/C0, MAX/(C5/C0)); }
         public long toMicros(long d)  { return x(d, C5/C1, MAX/(C5/C1)); }
         public long toMillis(long d)  { return x(d, C5/C2, MAX/(C5/C2)); }
         public long toSeconds(long d) { return x(d, C5/C3, MAX/(C5/C3)); }
         public long toMinutes(long d) { return x(d, C5/C4, MAX/(C5/C4)); }
         public long toHours(long d)   { return d; }
         public long toDays(long d)    { return d/(C6/C5); }
         public long convert(long d, TimeUnit u) { return u.toHours(d); }
         int excessNanos(long d, long m) { return 0; }
     },
     DAYS (6) {
         public long toNanos(long d)   { return x(d, C6/C0, MAX/(C6/C0)); }
         public long toMicros(long d)  { return x(d, C6/C1, MAX/(C6/C1)); }
         public long toMillis(long d)  { return x(d, C6/C2, MAX/(C6/C2)); }
         public long toSeconds(long d) { return x(d, C6/C3, MAX/(C6/C3)); }
         public long toMinutes(long d) { return x(d, C6/C4, MAX/(C6/C4)); }
         public long toHours(long d)   { return x(d, C6/C5, MAX/(C6/C5)); }
         public long toDays(long d)    { return d; }
         public long convert(long d, TimeUnit u) { return u.toDays(d); }
         int excessNanos(long d, long m) { return 0; }
     };

     /**
      * The index of this unit. This value is no longer used in this
      * version of this class, but is retained for serialization
      * compatibility with previous version.
      */
     private final int index;

     /** Internal constructor */
     TimeUnit(int index) {
         this.index = index;
     }

     // Handy constants for conversion methods
     static final long C0 = 1;
     static final long C1 = C0 * 1000;
     static final long C2 = C1 * 1000;
     static final long C3 = C2 * 1000;
     static final long C4 = C3 * 60;
     static final long C5 = C4 * 60;
     static final long C6 = C5 * 24;

     static final long MAX = Long.MAX_VALUE;

     /**
      * Scale d by m, checking for overflow.
      * This has a short name to make above code more readable.
      */
     static long x(long d, long m, long over) {
         if (d >  over) return Long.MAX_VALUE;
         if (d < -over) return Long.MIN_VALUE;
         return d * m;
     }

     /**
      * Convert the given time duration in the given unit to this
      * unit.  Conversions from finer to coarser granularities
      * truncate, so lose precision. For example converting
      * <tt>999</tt> milliseconds to seconds results in
      * <tt>0</tt>. Conversions from coarser to finer granularities
      * with arguments that would numerically overflow saturate to
      * <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt>
      * if positive.
      *
      * @param duration the time duration in the given <tt>unit</tt>
      * @param unit the unit of the <tt>duration</tt> argument
      * @return the converted duration in this unit,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      */
     public abstract long convert(long duration, TimeUnit unit);

     /**
      * Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toNanos(long duration);

     /**
      * Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toMicros(long duration);

     /**
      * Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toMillis(long duration);

     /**
      * Equivalent to <tt>SECONDS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toSeconds(long duration);

     /**
      * Equivalent to <tt>MINUTES.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toMinutes(long duration);

     /**
      * Equivalent to <tt>HOURS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration,
      * or <tt>Long.MIN_VALUE</tt> if conversion would negatively
      * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow.
      * @see #convert
      */
     public abstract long toHours(long duration);

     /**
      * Equivalent to <tt>DAYS.convert(duration, this)</tt>.
      * @param duration the duration
      * @return the converted duration
      * @see #convert
      */
     public abstract long toDays(long duration);

     /**
      * Utility to compute the excess-nanosecond argument to wait,
      * sleep, join.
      * @param d the duration
      * @param m the number of millisecondss
      * @return the number of nanoseconds
      */
     abstract int excessNanos(long d, long m);

     /**
      * Perform a timed <tt>Object.wait</tt> using this time unit.
      * This is a convenience method that converts timeout arguments
      * into the form required by the <tt>Object.wait</tt> method.
      *
      * <p>For example, you could implement a blocking <tt>poll</tt>
      * method (see {@link BlockingQueue#poll BlockingQueue.poll})
      * using:
      *
      * <pre>  public synchronized  Object poll(long timeout, TimeUnit unit) throws InterruptedException {
      *    while (empty) {
      *      unit.timedWait(this, timeout);
      *      ...
      *    }
      *  }</pre>
      *
      * @param obj the object to wait on
      * @param timeout the maximum time to wait.
      * @throws InterruptedException if interrupted while waiting.
      * @see Object#wait(long, int)
      */
     public void timedWait(Object obj, long timeout)
         throws InterruptedException {
         if (timeout > 0) {
             long ms = toMillis(timeout);
             int ns = excessNanos(timeout, ms);
             obj.wait(ms, ns);
         }
     }

     /**
      * Perform a timed <tt>Thread.join</tt> using this time unit.
      * This is a convenience method that converts time arguments into the
      * form required by the <tt>Thread.join</tt> method.
      * @param thread the thread to wait for
      * @param timeout the maximum time to wait
      * @throws InterruptedException if interrupted while waiting.
      * @see Thread#join(long, int)
      */
     public void timedJoin(Thread thread, long timeout)
         throws InterruptedException {
         if (timeout > 0) {
             long ms = toMillis(timeout);
             int ns = excessNanos(timeout, ms);
             thread.join(ms, ns);
         }
     }

     /**
      * Perform a <tt>Thread.sleep</tt> using this unit.
      * This is a convenience method that converts time arguments into the
      * form required by the <tt>Thread.sleep</tt> method.
      * @param timeout the minimum time to sleep
      * @throws InterruptedException if interrupted while sleeping.
      * @see Thread#sleep
      */
     public void sleep(long timeout) throws InterruptedException {
         if (timeout > 0) {
             long ms = toMillis(timeout);
             int ns = excessNanos(timeout, ms);
             Thread.sleep(ms, ns);
         }
     }

}
Revision:	1.24
Committed:	Thu Dec 30 17:57:38 2004 UTC (19 years, 5 months ago) by peierls
Branch:	MAIN
Changes since 1.23:	+10 -4 lines
Log Message:	Add overflow possibility to @returns entries for toSeconds(), toMinutes(), and toHours()
#	User	Rev	Content
1	dl	1.2	/*
2	dl	1.22	* 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	dl	1.2
7	tim	1.1	package java.util.concurrent;
8
9			/**
10	dl	1.22	* 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	peierls	1.23	* 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	dl	1.22	* 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	dl	1.20	public enum TimeUnit {
43	dl	1.22	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)((dC1) - (mC2)); }
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	peierls	1.24	* @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	dl	1.22	* @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	peierls	1.24	* @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	dl	1.22	* @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	peierls	1.24	* @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	dl	1.22	* @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	peierls	1.24	* @return the converted duration
236	dl	1.22	* @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 millisecondss
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 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.
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 {
272			if (timeout > 0) {
273			long ms = toMillis(timeout);
274			int ns = excessNanos(timeout, ms);
275			obj.wait(ms, ns);
276			}
277			}
278
279			/**
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
284			* @param timeout the maximum time to wait
285			* @throws InterruptedException if interrupted while waiting.
286			* @see Thread#join(long, int)
287			*/
288			public void timedJoin(Thread thread, long timeout)
289			throws InterruptedException {
290			if (timeout > 0) {
291			long ms = toMillis(timeout);
292			int ns = excessNanos(timeout, ms);
293			thread.join(ms, ns);
294			}
295			}
296
297			/**
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
302			* @throws InterruptedException if interrupted while sleeping.
303			* @see Thread#sleep
304			*/
305			public void sleep(long timeout) throws InterruptedException {
306			if (timeout > 0) {
307			long ms = toMillis(timeout);
308			int ns = excessNanos(timeout, ms);
309			Thread.sleep(ms, ns);
310			}
311			}
312	tim	1.1
313			}