org.apache.commons.collections.map
Class TransformedMap

java.lang.Object
  org.apache.commons.collections.map.AbstractMapDecorator
      org.apache.commons.collections.map.TransformedMap

All Implemented Interfaces:

java.io.Serializable, java.util.Map

Direct Known Subclasses:

TransformedSortedMap

public class TransformedMap
extends AbstractMapDecorator
implements java.io.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.

Note that TransformedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using Collections.synchronizedMap(Map). This class may throw exceptions when accessed by concurrent threads without synchronization.

This class is Serializable from Commons Collections 3.1.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne

See Also:

Serialized Form

Nested Class Summary

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

java.util.Map.Entry

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

Method Summary

protected java.lang.Object	checkSetValue(java.lang.Object value) Override to transform the value when using setValue.
static java.util.Map	decorate(java.util.Map map, Transformer keyTransformer, Transformer valueTransformer) Factory method to create a transforming map.
static java.util.Map	decorateTransform(java.util.Map map, Transformer keyTransformer, Transformer valueTransformer) Factory method to create a transforming map that will transform existing contents of the specified map.
java.util.Set	entrySet()
protected boolean	isSetValueChecking() Override to only return true when there is a value transformer.
java.lang.Object	put(java.lang.Object key, java.lang.Object value)
void	putAll(java.util.Map mapToCopy)
protected java.lang.Object	transformKey(java.lang.Object object) Transforms a key.
protected java.util.Map	transformMap(java.util.Map map) Transforms a map.
protected java.lang.Object	transformValue(java.lang.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(java.util.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:

java.lang.IllegalArgumentException - if map is null

Method Detail

decorate

public static java.util.Map decorate(java.util.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. Constrast this with decorateTransform(java.util.Map, org.apache.commons.collections.Transformer, org.apache.commons.collections.Transformer).

Parameters:

map - the map to decorate, must not be null

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

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

Throws:

java.lang.IllegalArgumentException - if map is null

decorateTransform

public static java.util.Map decorateTransform(java.util.Map map,
                                              Transformer keyTransformer,
                                              Transformer valueTransformer)

Factory method to create a transforming map that will transform existing contents of the specified map.

If there are any elements already in the map being decorated, they will be transformed by this method. Constrast this with decorate(java.util.Map, org.apache.commons.collections.Transformer, org.apache.commons.collections.Transformer).

Parameters:

map - the map to decorate, must not be null

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

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

Throws:

java.lang.IllegalArgumentException - if map is null

Since:

Commons Collections 3.2

transformKey

protected java.lang.Object transformKey(java.lang.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 java.lang.Object transformValue(java.lang.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 java.util.Map transformMap(java.util.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 java.lang.Object checkSetValue(java.lang.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 java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Specified by:

put in interface java.util.Map

Overrides:

put in class AbstractMapDecorator

putAll

public void putAll(java.util.Map mapToCopy)

Specified by:

putAll in interface java.util.Map

Overrides:

putAll in class AbstractMapDecorator

entrySet

public java.util.Set entrySet()

Specified by:

entrySet in interface java.util.Map

Overrides:

entrySet in class AbstractMapDecorator