org.apache.commons.collections.functors
Class SwitchTransformer
java.lang.Object
|
+--org.apache.commons.collections.functors.SwitchTransformer
- All Implemented Interfaces:
- Serializable, Transformer
- public class SwitchTransformer
- extends Object
- implements Transformer, Serializable
Transformer implementation calls the transformer whose predicate returns true,
like a switch statement.
- Since:
- Commons Collections 3.0
- Version:
- $Revision: 1.2 $ $Date: 2004/01/14 21:43:09 $
- Author:
- Stephen Colebourne
- See Also:
- Serialized Form
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SwitchTransformer
public SwitchTransformer(Predicate[] predicates,
Transformer[] transformers,
Transformer defaultTransformer)
- Constructor that performs no validation.
Use
getInstance
if you want that.
- Parameters:
predicates
- array of predicates, not cloned, no nullstransformers
- matching array of transformers, not cloned, no nullsdefaultTransformer
- the transformer to use if no match, null means nop
getInstance
public static Transformer getInstance(Predicate[] predicates,
Transformer[] transformers,
Transformer defaultTransformer)
- Factory method that performs validation and copies the parameter arrays.
- Parameters:
predicates
- array of predicates, cloned, no nullstransformers
- matching array of transformers, cloned, no nullsdefaultTransformer
- the transformer to use if no match, null means nop- Returns:
- the
chained
transformer - Throws:
IllegalArgumentException
- if array is nullIllegalArgumentException
- if any element in the array is null
getInstance
public static Transformer getInstance(Map predicatesAndTransformers)
- Create a new Transformer that calls one of the transformers depending
on the predicates.
The Map consists of Predicate keys and Transformer values. A transformer
is called if its matching predicate returns true. Each predicate is evaluated
until one returns true. If no predicates evaluate to true, the default
transformer is called. The default transformer is set in the map with a
null key. The ordering is that of the iterator() method on the entryset
collection of the map.
- Parameters:
predicatesAndTransformers
- a map of predicates to transformers- Returns:
- the
switch
transformer - Throws:
IllegalArgumentException
- if the map is nullIllegalArgumentException
- if any transformer in the map is nullClassCastException
- if the map elements are of the wrong type
transform
public Object transform(Object input)
- Execute the transformer whose predicate returns true.
- Specified by:
transform
in interface Transformer
- Following copied from interface:
org.apache.commons.collections.Transformer
- Parameters:
input
- the object to be transformed- Returns:
- a transformed object
- Throws:
ClassCastException
- (runtime) if the input is the wrong classIllegalArgumentException
- (runtime) if the input is invalidFunctorException
- (runtime) if the transform cannot be completed
Copyright © 2001-2004 Apache Software Foundation. All Rights Reserved.