Package 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:

java.io.Serializable, BinaryFunction<Generator<T>,T,T>, BinaryFunctor<Generator<T>,T>, Functor, UnaryFunction<Generator<T>,T>, UnaryFunctor<Generator<T>>

public class FoldLeft<T>
extends java.lang.Object
implements UnaryFunction<Generator<T>,T>, BinaryFunction<Generator<T>,T,T>, java.io.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:

$Revision$ $Date$

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	FoldLeft.FoldLeftHelper<T>	Helper procedure.

Field Summary

Fields

Modifier and Type	Field	Description
private BinaryFunction<? super T,? super T,? extends T>	function	BinaryFunction to apply to each (seed, next).
private static long	serialVersionUID	serialVersionUID declaration.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.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

Field Detail

serialVersionUID

private static final long serialVersionUID

serialVersionUID declaration.

See Also:

Constant Field Values

function

private final BinaryFunction<? super T,? super T,? extends T> function

BinaryFunction to apply to each (seed, next).

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(java.lang.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 java.lang.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 java.lang.Object

Returns:

a hash code for this functor

See Also:

Functor.equals(java.lang.Object)