com.bigdata.util.concurrent

Class Memoizer<A,V>

java.lang.Object

com.bigdata.util.concurrent.Memoizer<A,V>

All Implemented Interfaces:

Computable<A,V>

public abstract class Memoizer<A,V>
extends Object
implements Computable<A,V>

Pattern using a FutureTask to force synchronization only on tasks waiting for the same computation. This is based on Java Concurrency in Practice, page 108.

Concrete implementations MUST provide a means to limit the size of the cache. Because the cache is unbounded, it will just take on more and more memory as new results are computed. This could be handled by imposing a capacity constraint on the cache, by the use of WeakReferences if they can be made to stand for the specific computation to be performed, or by the use of a timeout on the cache entries.

Version:

$Id$

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
protected ConcurrentMap<A,Future<V>>	cache Cache accumulates results.

Constructor Summary

Constructors

Constructor and Description
Memoizer(Computable<A,V> c)

Method Summary

Methods

Modifier and Type	Method and Description
V	compute(A arg)

Methods inherited from class java.lang.Object

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

Field Detail

cache

protected final ConcurrentMap<A,Future<V>> cache

Cache accumulates results.

Constructor Detail

Memoizer

public Memoizer(Computable<A,V> c)

Method Detail

compute

public V compute(A arg)
          throws InterruptedException

Specified by:

compute in interface Computable<A,V>

Throws:

InterruptedException