org.apache.commons.functor.core.algorithm
Class FoldLeft<T>

java.lang.Object
  org.apache.commons.functor.core.algorithm.FoldLeft<T>

Type Parameters:

T - the returned evaluation type.

All Implemented Interfaces:

Serializable, BinaryFunction<Generator<T>,T,T>, BinaryFunctor<Generator<T>,T>, Functor, UnaryFunction<Generator<T>,T>, UnaryFunctor<Generator<T>>

public class FoldLeft<T>
extends Object
implements UnaryFunction<Generator<T>,T>, BinaryFunction<Generator<T>,T,T>, Serializable

Functional left-fold algorithm against the elements of a Generator. Uses the seed object (if supplied) as the initial left-side argument to the BinaryFunction, then uses the result of that evaluation as the next left-side argument, until the Generator's elements have been expended.

Version:

$Revision: 1171154 $ $Date: 2011-09-15 17:58:38 +0200 (Thu, 15 Sep 2011) $

See Also:

Serialized Form

Constructor Summary

FoldLeft(BinaryFunction<? super T,? super T,? extends T> func)
Create a new FoldLeft.

Method Summary

boolean	equals(Object obj) Indicates whether some other object is "equal to" this functor.
T	evaluate(Generator<T> obj) Evaluate this function.
T	evaluate(Generator<T> left, T right) Evaluate this function.
int	hashCode() Returns a hash code for this functor adhering to the general Object.hashCode contract.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.commons.functor.Functor

toString

Constructor Detail

FoldLeft

public FoldLeft(BinaryFunction<? super T,? super T,? extends T> func)

Create a new FoldLeft.

Parameters:

func - BinaryFunction to apply to each (seed, next)

Method Detail

evaluate

public final T evaluate(Generator<T> obj)

Evaluate this function.

Specified by:

evaluate in interface UnaryFunction<Generator<T>,T>

Parameters:

obj - Generator to transform

Returns:

the T result of this evaluation

evaluate

public final T evaluate(Generator<T> left,
                        T right)

Evaluate this function.

Specified by:

evaluate in interface BinaryFunction<Generator<T>,T,T>

Parameters:

left - Generator to transform

right - initial left-side seed object

Returns:

the T result of this function for the given arguments

equals

public boolean equals(Object obj)

Indicates whether some other object is "equal to" this functor. This method must adhere to general Object.equals contract. Additionally, this method can return true only if the specified Object implements the same functor interface and is known to produce the same results and/or side-effects for the same arguments (if any).

While implementators are strongly encouraged to override the default Object implementation of this method, note that the default Object implementation does in fact adhere to the functor equals contract.

Specified by:

equals in interface Functor

Overrides:

equals in class Object

Parameters:

obj - the object to compare this functor to

Returns:

true iff the given object implements this functor interface, and is known to produce the same results and/or side-effects for the same arguments (if any).

See Also:

Functor.hashCode()

hashCode

public int hashCode()

Returns a hash code for this functor adhering to the general Object.hashCode contract. Implementators are strongly encouraged but not strictly required to override the default Object implementation of this method.

Specified by:

hashCode in interface Functor

Overrides:

hashCode in class Object

Returns:

a hash code for this functor

See Also:

Functor.equals(java.lang.Object)