org.apache.commons.collections.functors
Class SwitchClosure

java.lang.Object
  |
  +--org.apache.commons.collections.functors.SwitchClosure
All Implemented Interfaces:
Closure, Serializable

public class SwitchClosure
extends Object
implements Closure, Serializable

Closure implementation calls the closure 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

Constructor Summary
SwitchClosure(Predicate[] predicates, Closure[] closures, Closure defaultClosure)
          Constructor that performs no validation.
 
Method Summary
 void execute(Object input)
          Execute the closure whose predicate returns true
static Closure getInstance(Map predicatesAndClosures)
          Create a new Closure that calls one of the closures depending on the predicates.
static Closure getInstance(Predicate[] predicates, Closure[] closures, Closure defaultClosure)
          Factory method that performs validation and copies the parameter arrays.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SwitchClosure

public SwitchClosure(Predicate[] predicates,
                     Closure[] closures,
                     Closure defaultClosure)
Constructor that performs no validation. Use getInstance if you want that.
Parameters:
predicates - array of predicates, not cloned, no nulls
closures - matching array of closures, not cloned, no nulls
defaultClosure - the closure to use if no match, null means nop
Method Detail

getInstance

public static Closure getInstance(Predicate[] predicates,
                                  Closure[] closures,
                                  Closure defaultClosure)
Factory method that performs validation and copies the parameter arrays.
Parameters:
predicates - array of predicates, cloned, no nulls
closures - matching array of closures, cloned, no nulls
defaultClosure - the closure to use if no match, null means nop
Returns:
the chained closure
Throws:
IllegalArgumentException - if array is null
IllegalArgumentException - if any element in the array is null

getInstance

public static Closure getInstance(Map predicatesAndClosures)
Create a new Closure that calls one of the closures depending on the predicates.

The Map consists of Predicate keys and Closure values. A closure is called if its matching predicate returns true. Each predicate is evaluated until one returns true. If no predicates evaluate to true, the default closure is called. The default closure 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:
predicatesAndClosures - a map of predicates to closures
Returns:
the switch closure
Throws:
IllegalArgumentException - if the map is null
IllegalArgumentException - if any closure in the map is null
ClassCastException - if the map elements are of the wrong type

execute

public void execute(Object input)
Execute the closure whose predicate returns true
Specified by:
execute in interface Closure
Following copied from interface: org.apache.commons.collections.Closure
Parameters:
input - the input to execute on
Throws:
ClassCastException - (runtime) if the input is the wrong class
IllegalArgumentException - (runtime) if the input is invalid
FunctorException - (runtime) if any other error occurs


Copyright © 2001-2004 Apache Software Foundation. All Rights Reserved.