eaLib API Docs
Last Modified : January 7 2002

mss.ea.al
Interface Sync

All Known Implementing Classes:
CountingMutex, Mutex

public interface Sync

Main interface for locks, gates, and conditions.

Since:
0.2
Version:
$Revision: 1.3 $ $Date: 2001/11/13 10:02:17 $
Author:
Doug Lea

Field Summary
static long ONE_CENTURY
          One century in milliseconds; convenient as a time-out value
static long ONE_DAY
          One day, in milliseconds; convenient as a time-out value
static long ONE_HOUR
          One hour, in milliseconds; convenient as a time-out value
static long ONE_MINUTE
          One minute, in milliseconds; convenient as a time-out value
static long ONE_SECOND
          One second, in milliseconds; convenient as a time-out value
static long ONE_WEEK
          One week, in milliseconds; convenient as a time-out value
static long ONE_YEAR
          One year in milliseconds; convenient as a time-out value
 
Method Summary
 void acquire()
          Wait (possibly forever) until successful passage.
 boolean attempt(long msecs)
          Wait at most msecs to pass; report whether passed.
 void release()
          Potentially enable others to pass.
 

Field Detail

ONE_SECOND

public static final long ONE_SECOND
One second, in milliseconds; convenient as a time-out value

ONE_MINUTE

public static final long ONE_MINUTE
One minute, in milliseconds; convenient as a time-out value

ONE_HOUR

public static final long ONE_HOUR
One hour, in milliseconds; convenient as a time-out value

ONE_DAY

public static final long ONE_DAY
One day, in milliseconds; convenient as a time-out value

ONE_WEEK

public static final long ONE_WEEK
One week, in milliseconds; convenient as a time-out value

ONE_YEAR

public static final long ONE_YEAR
One year in milliseconds; convenient as a time-out value

ONE_CENTURY

public static final long ONE_CENTURY
One century in milliseconds; convenient as a time-out value
Method Detail

acquire

public void acquire()
             throws java.lang.InterruptedException
Wait (possibly forever) until successful passage. Fail only upon interuption. Interruptions always result in `clean' failures. On failure, you can be sure that it has not been acquired, and that no corresponding release should be performed. Conversely, a normal return guarantees that the acquire was successful.

attempt

public boolean attempt(long msecs)
                throws java.lang.InterruptedException
Wait at most msecs to pass; report whether passed.

The method has best-effort semantics: The msecs bound cannot be guaranteed to be a precise upper bound on wait time in Java. Implementations generally can only attempt to return as soon as possible after the specified bound. Also, timers in Java do not stop during garbage collection, so timeouts can occur just because a GC intervened. So, msecs arguments should be used in a coarse-grained manner. Further, implementations cannot always guarantee that this method will return at all without blocking indefinitely when used in unintended ways. For example, deadlocks may be encountered when called in an unintended context.

Parameters:
msecs - the number of milleseconds to wait. An argument less than or equal to zero means not to wait at all. However, this may still require access to a synchronization lock, which can impose unbounded delay if there is a lot of contention among threads.
Returns:
true if acquired

release

public void release()
Potentially enable others to pass.

Because release does not raise exceptions, it can be used in `finally' clauses without requiring extra embedded try/catch blocks. But keep in mind that as with any java method, implementations may still throw unchecked exceptions such as Error or NullPointerException when faced with uncontinuable errors. However, these should normally only be caught by higher-level error handlers.


eaLib API Docs
Last Modified : January 7 2002

Copyright © 2000-2001 Technical University of Ilmenau, Department ESS