org.codehaus.groovy.runtime

Class ComposedClosure<V>

java.lang.Object

groovy.lang.GroovyObjectSupport

groovy.lang.Closure<V>

org.codehaus.groovy.runtime.ComposedClosure<V>

All Implemented Interfaces:

GroovyCallable<V>, GroovyObject, Serializable, Cloneable, Runnable, Callable<V>

public final class ComposedClosure<V>
extends Closure<V>

A wrapper for Closure to support composition. Normally used only internally through the rightShift() and leftShift() methods on Closure.

Typical usages:

 def twice = { a -> a * 2 }
 def inc = { b -> b + 1 }
 def f = { x -> twice(inc(x)) } // longhand
 def g = inc >> twice
 def h = twice << inc
 assert f(10) == 22
 assert g(10) == 22
 assert h(10) == 22

 def s2c = { it.chars[0] }
 def p = Integer.&toHexString >> s2c >> Character.&toUpperCase
 assert p(15) == 'F'

 def multiply = { a, b -> a * b }
 def identity = { a -> [a, a] }
 def sq = identity >> multiply
 assert (1..5).collect{ sq(it) } == [1, 4, 9, 16, 25]

 def add3 = { a, b, c -> a + b + c }
 def add2plus10 = add3.curry(10)
 def multBoth = { a, b, c -> [a*c, b*c] }
 def twiceBoth = multBoth.rcurry(2)
 def twiceBothPlus10 = twiceBoth >> add2plus10
 assert twiceBothPlus10(5, 10) == 40
 

Author:

Paul King

See Also:

Serialized Form

Field Summary

Fields inherited from class groovy.lang.Closure

DELEGATE_FIRST, DELEGATE_ONLY, DONE, IDENTITY, maximumNumberOfParameters, OWNER_FIRST, OWNER_ONLY, parameterTypes, SKIP, TO_SELF

Constructor Summary

Constructors

Constructor and Description
ComposedClosure(Closure first, Closure<V> second)

Method Summary

Methods

Modifier and Type	Method and Description
V	call(Object... args)
Object	clone()
Object	doCall(Object... args)
Object	getDelegate()
Class[]	getParameterTypes()
int	getResolveStrategy() Gets the strategy which the closure users to resolve methods and properties
void	setDelegate(Object delegate) Allows the delegate to be changed such as when performing markup building
void	setResolveStrategy(int resolveStrategy) Sets the strategy which the closure uses to resolve property references.

Methods inherited from class groovy.lang.Closure

asWritable, call, call, curry, getDirective, getMaximumNumberOfParameters, getOwner, getProperty, getThisObject, isCase, leftShift, leftShift, memoize, memoizeAtLeast, memoizeAtMost, memoizeBetween, ncurry, ncurry, rcurry, rcurry, rightShift, run, setDirective, setProperty, throwRuntimeException, trampoline, trampoline

Methods inherited from class groovy.lang.GroovyObjectSupport

getMetaClass, invokeMethod, setMetaClass

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ComposedClosure

public ComposedClosure(Closure first,
               Closure<V> second)

Method Detail

setDelegate

public void setDelegate(Object delegate)

Description copied from class: Closure

Allows the delegate to be changed such as when performing markup building

Overrides:

setDelegate in class Closure<V>

Parameters:

delegate - the new delegate

getDelegate

public Object getDelegate()

Overrides:

getDelegate in class Closure<V>

Returns:

the delegate Object to which method calls will go which is typically the outer class when the closure is constructed

setResolveStrategy

public void setResolveStrategy(int resolveStrategy)

Description copied from class: Closure

Sets the strategy which the closure uses to resolve property references. The default is Closure.OWNER_FIRST

Overrides:

setResolveStrategy in class Closure<V>

Parameters:

resolveStrategy - The resolve strategy to set

See Also:

Closure.DELEGATE_FIRST, Closure.DELEGATE_ONLY, Closure.OWNER_FIRST, Closure.OWNER_ONLY, Closure.TO_SELF

getResolveStrategy

public int getResolveStrategy()

Description copied from class: Closure

Gets the strategy which the closure users to resolve methods and properties

Overrides:

getResolveStrategy in class Closure<V>

Returns:

The resolve strategy

See Also:

Closure.DELEGATE_FIRST, Closure.DELEGATE_ONLY, Closure.OWNER_FIRST, Closure.OWNER_ONLY, Closure.TO_SELF

clone

public Object clone()

Overrides:

clone in class Closure<V>

getParameterTypes

public Class[] getParameterTypes()

Overrides:

getParameterTypes in class Closure<V>

Returns:

the parameter types of the longest doCall method of this closure

doCall

public Object doCall(Object... args)

call

public V call(Object... args)

Overrides:

call in class Closure<V>