org.apache.commons.collections.collection
Class TransformedCollection<I,O>

java.lang.Object
  org.apache.commons.collections.collection.AbstractCollectionDecorator<E>
      org.apache.commons.collections.collection.AbstractSerializableCollectionDecorator
          org.apache.commons.collections.collection.TransformedCollection<I,O>

All Implemented Interfaces:

Serializable, Iterable, Collection

Direct Known Subclasses:

TransformedBag, TransformedBuffer, TransformedList, TransformedSet

public class TransformedCollection<I,O>
extends AbstractSerializableCollectionDecorator

Decorates another Collection to transform objects that are added.

The add methods 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 Collection 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

Field Summary

protected Transformer<? super I,? extends O>

transformer The transformer to use

Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

collection

Constructor Summary

protected

TransformedCollection(Collection<I> coll, Transformer<? super I,? extends O> transformer) Constructor that wraps (not copies).

Method Summary

boolean	add(Object object)
boolean	addAll(Collection coll)
boolean	addAllTyped(Collection<? extends I> coll) A better typed version of the addAll method (although breaks the Collection interface).
boolean	addTyped(I object) A better typed version of the add method (although breaks the Collection interface).
static <I,O> Collection<O>	decorate(Collection<I> coll, Transformer<? super I,? extends O> transformer) Factory method to create a transforming collection.
protected Collection<O>	transform(Collection<? extends I> coll) Transforms a collection.
protected O	transform(I object) Transforms an object.

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

clear, contains, containsAll, equals, getCollection, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Field Detail

transformer

protected final Transformer<? super I,? extends O> transformer

The transformer to use

Constructor Detail

TransformedCollection

protected TransformedCollection(Collection<I> coll,
                                Transformer<? super I,? extends O> transformer)

Constructor that wraps (not copies).

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

Parameters:

coll - the collection to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Throws:

IllegalArgumentException - if collection or transformer is null

Method Detail

decorate

public static <I,O> Collection<O> decorate(Collection<I> coll,
                                           Transformer<? super I,? extends O> transformer)

Factory method to create a transforming collection.

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

Parameters:

coll - the collection to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Returns:

a new transformed collection

Throws:

IllegalArgumentException - if collection or transformer is null

transform

protected O transform(I object)

Transforms an object.

The transformer itself may throw an exception if necessary.

Parameters:

object - the object to transform

Returns:

a transformed object

transform

protected Collection<O> transform(Collection<? extends I> coll)

Transforms a collection.

The transformer itself may throw an exception if necessary.

Parameters:

coll - the collection to transform

Returns:

a transformed object

add

public boolean add(Object object)

Specified by:

add in interface Collection

Overrides:

add in class AbstractCollectionDecorator

addTyped

public boolean addTyped(I object)

A better typed version of the add method (although breaks the Collection interface).

addAll

public boolean addAll(Collection coll)

Specified by:

addAll in interface Collection

Overrides:

addAll in class AbstractCollectionDecorator

addAllTyped

public boolean addAllTyped(Collection<? extends I> coll)

A better typed version of the addAll method (although breaks the Collection interface).