org.faktorips.runtime.caching
Class Memoizer<K,V>

java.lang.Object
  org.faktorips.runtime.caching.Memoizer<K,V>

All Implemented Interfaces:

IComputable<K,V>

public class Memoizer<K,V>
extends Object
implements IComputable<K,V>

This Memoizer is implemented as suggested by Brian Goetz in Java Concurrency in Practice. It is a thread safe caching mechanism that loads not stored object by calling a IComputable. It is extended by the soft reference mechanism so references could be garbage collected in case of memory needs.

Author:

dirmeier

Constructor Summary

Memoizer(IComputable<K,V> computable)
The constructor to create a memoizer with default values for the internal ConcurrentHashMap

Memoizer(IComputable<K,V> computable, int initSize, float loadFactor, int concurrencyLevel)
This constructor needs next to the IComputable also the initial size, the load factor and the concurrency level.

Method Summary

V	compute(K key) Compute an object of type V identified by the key of type K
Class<? super V>	getValueClass() Getting the Class of the value this computable produces.
static RuntimeException	launderThrowable(Throwable t) Coerce an unchecked Throwable to a RuntimeException If the Throwable is an Error, throw it; if it is a RuntimeException return it, otherwise throw IllegalStateException

Methods inherited from class java.lang.Object

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

Constructor Detail

Memoizer

public Memoizer(IComputable<K,V> computable)

The constructor to create a memoizer with default values for the internal ConcurrentHashMap

Parameters:

computable - the IComputable to load new items

Memoizer

public Memoizer(IComputable<K,V> computable,
                int initSize,
                float loadFactor,
                int concurrencyLevel)

This constructor needs next to the IComputable also the initial size, the load factor and the concurrency level. These parameters are only for tuning purpose and are directly forwarded to the internal ConcurrentHashMap.

Parameters:

computable - The IComputable to load new items

initSize - the initial size @see ConcurrentHashMap

loadFactor - the load factor @see ConcurrentHashMap

concurrencyLevel - the concurrency level @see ConcurrentHashMap

Method Detail

compute

public V compute(K key)
          throws InterruptedException

Description copied from interface: IComputable

Compute an object of type V identified by the key of type K

Specified by:

compute in interface IComputable<K,V>

Parameters:

key - the key to identify the object

Returns:

the computed Object of type V

Throws:

InterruptedException - When computation was interrupted

launderThrowable

public static RuntimeException launderThrowable(Throwable t)

Coerce an unchecked Throwable to a RuntimeException

If the Throwable is an Error, throw it; if it is a RuntimeException return it, otherwise throw IllegalStateException

getValueClass

public Class<? super V> getValueClass()

Description copied from interface: IComputable

Getting the Class of the value this computable produces.

Specified by:

getValueClass in interface IComputable<K,V>