com.bigdata.concurrent

Class NamedReadWriteLock<T>

java.lang.Object

com.bigdata.concurrent.NamedReadWriteLock<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 NamedReadWriteLock<T>
extends Object

A factory for named ReadWriteLocks. A simple ReadWriteLock manages access to a single resource. However, a NamedReadWriteLock 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
NamedReadWriteLock()

Method Summary

Methods

Modifier and Type	Method and Description
Lock	acquireReadLock(T name) Block until the ReentrantReadWriteLock.ReadLock for the named resource is available, then Lock.lock() the Lock and returns the Lock.
Lock	acquireReadLock(T name, long timeout, TimeUnit unit)
Lock	acquireWriteLock(T name)
Lock	acquireWriteLock(T name, long timeout, TimeUnit unit)
protected ReentrantReadWriteLock	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

NamedReadWriteLock

public NamedReadWriteLock()

Method Detail

lockFactory

protected ReentrantReadWriteLock 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.

acquireReadLock

public Lock acquireReadLock(T name)

Block until the ReentrantReadWriteLock.ReadLock for the named resource is available, then Lock.lock() the Lock and returns the Lock.

Parameters:

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

Returns:

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

acquireReadLock

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

Throws:

InterruptedException

TimeoutException

acquireWriteLock

public Lock acquireWriteLock(T name)

acquireWriteLock

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

Throws:

InterruptedException

TimeoutException