org.apache.commons.collections.map
Class TransformedMap

java.lang.Object
  org.apache.commons.collections.map.AbstractMapDecorator<K,V>
      org.apache.commons.collections.map.TransformedMap

All Implemented Interfaces:

Serializable, Map

Direct Known Subclasses:

TransformedSortedMap

public class TransformedMap
extends AbstractMapDecorator<K,V>
implements Serializable

Decorates another Map to transform objects that are added.

The Map put methods and Map.Entry setValue method are affected by this class. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.

This class is Serializable from Commons Collections 3.1.

Note: This class cannot support generics without breaking the Map contract.

Since:

Commons Collections 3.0

Version:

$Revision: 1.2 $ $Date: 2005/05/23 14:42:13 $

Author:

Matt Hall, John Watkinson, Stephen Colebourne

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

protected Transformer	keyTransformer The transformer to use for the key
protected Transformer	valueTransformer The transformer to use for the value

Fields inherited from class org.apache.commons.collections.map.AbstractMapDecorator

map

Constructor Summary

protected

TransformedMap(Map map, Transformer keyTransformer, Transformer valueTransformer) Constructor that wraps (not copies).

Method Summary

protected Object	checkSetValue(Object value) Override to transform the value when using setValue.
static Map	decorate(Map map, Transformer keyTransformer, Transformer valueTransformer) Factory method to create a transforming map.
Set<Map.Entry<K,V>>	entrySet()
protected boolean	isSetValueChecking() Override to only return true when there is a value transformer.
Object	put(Object key, Object value)
void	putAll(Map mapToCopy)
protected Object	transformKey(Object object) Transforms a key.
protected Map	transformMap(Map map) Transforms a map.
protected Object	transformValue(Object object) Transforms a value.

Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator

clear, containsKey, containsValue, equals, get, getMap, hashCode, isEmpty, keySet, remove, size, toString, values

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

keyTransformer

protected final Transformer keyTransformer

The transformer to use for the key

valueTransformer

protected final Transformer valueTransformer

The transformer to use for the value

Constructor Detail

TransformedMap

protected TransformedMap(Map map,
                         Transformer keyTransformer,
                         Transformer valueTransformer)

Constructor that wraps (not copies).

If there are any elements already in the collection being decorated, they are NOT transformed.

Parameters:

map - the map to decorate, must not be null

keyTransformer - the transformer to use for key conversion, null means no conversion

valueTransformer - the transformer to use for value conversion, null means no conversion

Throws:

IllegalArgumentException - if map is null

Method Detail

decorate

public static Map decorate(Map map,
                           Transformer keyTransformer,
                           Transformer valueTransformer)

Factory method to create a transforming map.

If there are any elements already in the map being decorated, they are NOT transformed.

Parameters:

map - the map to decorate, must not be null

keyTransformer - the transformer to use for key conversion, null means no conversion

valueTransformer - the transformer to use for value conversion, null means no conversion

Throws:

IllegalArgumentException - if map is null

transformKey

protected Object transformKey(Object object)

Transforms a key.

The transformer itself may throw an exception if necessary.

Parameters:

object - the object to transform

Throws:

the - transformed object

transformValue

protected Object transformValue(Object object)

Transforms a value.

The transformer itself may throw an exception if necessary.

Parameters:

object - the object to transform

Throws:

the - transformed object

transformMap

protected Map transformMap(Map map)

Transforms a map.

The transformer itself may throw an exception if necessary.

Parameters:

map - the map to transform

Throws:

the - transformed object

checkSetValue

protected Object checkSetValue(Object value)

Override to transform the value when using setValue.

Parameters:

value - the value to transform

Returns:

the transformed value

Since:

Commons Collections 3.1

isSetValueChecking

protected boolean isSetValueChecking()

Override to only return true when there is a value transformer.

Returns:

true if a value transformer is in use

Since:

Commons Collections 3.1

put

public Object put(Object key,
                  Object value)

Specified by:

put in interface Map

Overrides:

put in class AbstractMapDecorator

putAll

public void putAll(Map mapToCopy)

Specified by:

putAll in interface Map

Overrides:

putAll in class AbstractMapDecorator

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

Overrides:

entrySet in class AbstractMapDecorator<K,V>