com.abstractics.utils.converter
Class CachingConverterWrapper

java.lang.Object
  com.abstractics.utils.converter.CachingConverterWrapper

All Implemented Interfaces:

ObjectConverter

public class CachingConverterWrapper

extends java.lang.Object

implements ObjectConverter

An instance of ObjectConverter that can wrap another ObjectConverter and provide caching for the objects that are converted. An example is the ConverterImageIcon class that is often wrapped to provide a cache for the loaded images.

 ConvertObject.register(new CachingConverterWrapper(new ConverterImageIcon()));
 

When an object is asked to be converted, it's toString() method is called to determine a key for the cache. If an object is already in the cache with that key, then it is returned. Otherwise the wrapped converter is used to do the conversion and the result is cached with the key.
NOTE: Since the toString() method is used to determine keys, it becomes important that they are unique. This is often the case beacuse Strings are the objects being converted, but be aware.

Version:

$Id: CachingConverterWrapper.java,v 1.2 2006/03/15 05:37:30 andyman99 Exp $

Author:

Andrew Lawrence, Copyright 2006 Abstractics, L.L.C., Licensed under the Apache License, Version 2.0

Constructor Summary

CachingConverterWrapper(ObjectConverter wrappedConverter)

Method Summary

java.lang.Object	convert(java.lang.Object obj, java.util.Locale locale) Implemented here to intercept conversion calls and check for the objects in the cache first.
java.lang.Class	getClassToConvertTo()

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingConverterWrapper

public CachingConverterWrapper(ObjectConverter wrappedConverter)

Parameters:

wrappedConverter - The ObjectConverter object to wrap, intercepting its calls to cache them

Method Detail

convert

public java.lang.Object convert(java.lang.Object obj,
                                java.util.Locale locale)
                         throws ObjectConverterException

Implemented here to intercept conversion calls and check for the objects in the cache first. The given object has its toString() method called to determine the key for the cache Map. If an object with that key already exists, then it is returned. Otherwise the wrappedConverter specified in the constructor is called to do the conversion. The resulting object is then stored in the cache

Specified by:

convert in interface ObjectConverter

Parameters:

obj - Object to be converted. Guaranteed not to be null and not to already be an instanceof the Class returned by ObjectConverter.getClassToConvertTo(). Those conditions are checked before the converter is even called.

locale - The locale that is asking for the conversion. This may or may not be necessary for the conversion.

Returns:

The converted object - should NEVER return anything that is not an instanceof the class returned by ObjectConverter.getClassToConvertTo()

Throws:

ObjectConverterException - Throw this exception if the string cannot be converted, for whatever reason.

See Also:

com.abstractics.utils.converter.ObjectConverter#convert(java.lang.Object)

getClassToConvertTo

public java.lang.Class getClassToConvertTo()

Specified by:

getClassToConvertTo in interface ObjectConverter

Returns:

The class that this converter converts to