Package org.eclipse.aether.named

Interface NamedLock

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

AdaptedSemaphoreNamedLock, CompositeNamedLock, FileLockNamedLock, NamedLockSupport, ReadWriteLockNamedLock

public interface NamedLock
extends AutoCloseable

A named lock, functionally similar to existing JVM and other implementations. Must support boxing (reentrancy), but no lock upgrade is supported. The lock instance obtained from lock factory must be treated as a resource, best in try-with-resource block. Usual pattern to use this lock:

   try (NamedLock lock = factory.getLock("resourceName")) {
     if (lock.lockExclusively(10L, Timeunit.SECONDS)) {
       try {
         ... exclusive access to "resourceName" resource gained here
       }
       finally {
         lock.unlock();
       }
     }
     else {
       ... failed to gain access within specified time, handle it
     }
   }
 

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the lock resource.
NamedLockKey	key()	Returns this instance key, never null.
boolean	lockExclusively(long time, TimeUnit unit)	Tries to lock exclusively, may block for given time.
boolean	lockShared(long time, TimeUnit unit)	Tries to lock shared, may block for given time.
void	unlock()	Unlocks the lock, must be invoked by caller after one of the lockShared(long, TimeUnit) or lockExclusively(long, TimeUnit).

Method Details

key

NamedLockKey key()

Returns this instance key, never null.

lockShared

boolean lockShared(long time,
 TimeUnit unit)
            throws InterruptedException

Tries to lock shared, may block for given time. If successful, returns true.

Throws:

InterruptedException

lockExclusively

boolean lockExclusively(long time,
 TimeUnit unit)
                 throws InterruptedException

Tries to lock exclusively, may block for given time. If successful, returns true.

Throws:

InterruptedException

unlock

void unlock()

Unlocks the lock, must be invoked by caller after one of the lockShared(long, TimeUnit) or lockExclusively(long, TimeUnit).

close

void close()

Closes the lock resource. Lock MUST be unlocked using unlock() in case any locking happened on it. After invoking this method, the lock instance MUST NOT be used anymore. If lock for same name needed, a new instance should be obtained from factory using NamedLockFactory.getLock(java.util.Collection). Ideally, instances are to be used within try-with-resource blocks, so calling this method directly is not really needed, nor advised.

Specified by:

close in interface AutoCloseable