Package 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:
Serializable, Map
Direct Known Subclasses:
TransformedSortedMap
public class TransformedMap extends AbstractMapDecorator 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.

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 14:33:15 +0200 (Thu, 10 Apr 2008) $
Author:
Stephen Colebourne
See Also:

  • Field Details

    • 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 Details

    • 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 Details

    • 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. 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:
      IllegalArgumentException - if map is null

    • decorateTransform

      public static Map decorateTransform(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:
      IllegalArgumentException - if map is null
      Since:
      Commons Collections 3.2

    • 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 entrySet()
      Specified by:
      entrySet in interface Map
      Overrides:
      entrySet in class AbstractMapDecorator