com.bigdata.concurrent

Class NamedLock<T>

java.lang.Object

com.bigdata.concurrent.NamedLock<T>

Type Parameters:

T - The generic type for the "name". This MUST implement hashCode() and equals() since the instances of this type will serve as keys in a Map.

public class NamedLock<T>
extends Object

A factory for named Locks. A simple Lock manages access to a single resource. However, a NamedLock manages access to the members of a set of named resources. This is more efficient when the latency of the operation once the lock is acquired is significant, e.g., an RMI call or a disk IO.

The locks are stored in a WeakHashMap so that they will be garbage collected if there are no threads waiting in the queue for a given named lock.

Version:

$Id$

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
NamedLock()

Method Summary

Methods

Modifier and Type	Method and Description
Lock	acquireLock(T name) Block until the Lock for the named resource is available, then Lock.lock() the Lock and return the locked Lock.
Lock	acquireLock(T name, long timeout, TimeUnit unit)
protected Lock	lockFactory(T name) Return the canonical instance of the lock for a named resource.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NamedLock

public NamedLock()

Method Detail

lockFactory

protected Lock lockFactory(T name)

Return the canonical instance of the lock for a named resource.

Parameters:

name - The name.

Returns:

The canonical instance of the lock for that name.

acquireLock

public Lock acquireLock(T name)

Block until the Lock for the named resource is available, then Lock.lock() the Lock and return the locked Lock.

Parameters:

name - The name of the resource whose Lock is desired.

Returns:

The Lock. It will have already been Lock.lock()ed.

acquireLock

public Lock acquireLock(T name,
               long timeout,
               TimeUnit unit)
                 throws InterruptedException,
                        TimeoutException

Throws:

InterruptedException

TimeoutException