org.apache.commons.collections.functors
Class SwitchClosure

java.lang.Object
  org.apache.commons.collections.functors.SwitchClosure

All Implemented Interfaces:

java.io.Serializable, Closure

public class SwitchClosure
extends java.lang.Object
implements Closure, java.io.Serializable

Closure implementation calls the closure whose predicate returns true, like a switch statement.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

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(java.lang.Object input) Executes the closure whose matching predicate returns true
Closure[]	getClosures() Gets the closures, do not modify the array.
Closure	getDefaultClosure() Gets the default closure.
static Closure	getInstance(java.util.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.
Predicate[]	getPredicates() Gets the predicates, do not modify the array.

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:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if any element in the array is null

getInstance

public static Closure getInstance(java.util.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:

java.lang.IllegalArgumentException - if the map is null

java.lang.IllegalArgumentException - if any closure in the map is null

java.lang.ClassCastException - if the map elements are of the wrong type

execute

public void execute(java.lang.Object input)

Executes the closure whose matching predicate returns true

Specified by:

execute in interface Closure

Parameters:

input - the input object

getPredicates

public Predicate[] getPredicates()

Gets the predicates, do not modify the array.

Returns:

the predicates

Since:

Commons Collections 3.1

getClosures

public Closure[] getClosures()

Gets the closures, do not modify the array.

Returns:

the closures

Since:

Commons Collections 3.1

getDefaultClosure

public Closure getDefaultClosure()

Gets the default closure.

Returns:

the default closure

Since:

Commons Collections 3.1