org.apache.commons.collections.collection

## Class TransformedCollection

- java.lang.Object
- - org.apache.commons.collections.collection.AbstractCollectionDecorator
  - - org.apache.commons.collections.collection.AbstractSerializableCollectionDecorator
    - - org.apache.commons.collections.collection.TransformedCollection

- All Implemented Interfaces:
    Serializable, Iterable, Collection
  Direct Known Subclasses:
    TransformedBag, TransformedBuffer, TransformedList, TransformedSet

      public class TransformedCollection
      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.

  Since:
    Commons Collections 3.0
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    Stephen Colebourne
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected Transformer` | `transformer` The transformer to use

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

      `collection`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `TransformedCollection(Collection coll, Transformer transformer)` Constructor that wraps (not copies).

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `add(Object object)`
    `boolean` | `addAll(Collection coll)`
    `static Collection` | `decorate(Collection coll, Transformer transformer)` Factory method to create a transforming collection.
    `protected Collection` | `transform(Collection coll)` Transforms a collection.
    `protected Object` | `transform(Object 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 transformer

      The transformer to use

  - ### Constructor Detail

    - #### TransformedCollection

          protected TransformedCollection(Collection coll,
                               Transformer 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 Collection decorate(Collection coll,
                            Transformer 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 Object transform(Object 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 transform(Collection 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`

    - #### addAll

          public boolean addAll(Collection coll)

      Specified by:
        `addAll` in interface `Collection`
      Overrides:
        `addAll` in class `AbstractCollectionDecorator`

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