Package org.apache.commons.collections4.iterators

Class TransformIterator<I,O>

java.lang.Object

org.apache.commons.collections4.iterators.TransformIterator<I,O>

Type Parameters:

I - the type of the input to the function.

O - the type of the result of the function.

All Implemented Interfaces:

Iterator<O>

public class TransformIterator<I,O>
extends Object
implements Iterator<O>

Decorates an iterator such that each element returned is transformed.

Since:

1.0

Constructor Summary

Constructors

Constructor	Description
TransformIterator()	Constructs a new TransformIterator that will not function until the setIterator and setTransformer(Transformer) methods are invoked.
TransformIterator(Iterator<? extends I> iterator)	Constructs a new TransformIterator that won't transform elements from the given iterator.
TransformIterator(Iterator<? extends I> iterator, Transformer<? super I,? extends O> transformer)	Constructs a new TransformIterator that will use the given iterator and transformer.

Method Summary

Modifier and Type	Method	Description
Iterator<? extends I>	getIterator()	Gets the iterator this iterator is using.
Transformer<? super I,? extends O>	getTransformer()	Gets the transformer this iterator is using.
boolean	hasNext()
O	next()	Gets the next object from the iteration, transforming it using the current transformer.
void	remove()
void	setIterator(Iterator<? extends I> iterator)	Sets the iterator for this iterator to use.
void	setTransformer(Transformer<? super I,? extends O> transformer)	Sets the transformer this the iterator to use.
protected O	transform(I source)	Transforms the given object using the transformer.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Details

TransformIterator

public TransformIterator()

Constructs a new TransformIterator that will not function until the setIterator and setTransformer(Transformer) methods are invoked.

TransformIterator

public TransformIterator(Iterator<? extends I> iterator)

Constructs a new TransformIterator that won't transform elements from the given iterator.

Parameters:

iterator - the iterator to use

TransformIterator

public TransformIterator(Iterator<? extends I> iterator,
 Transformer<? super I,? extends O> transformer)

Constructs a new TransformIterator that will use the given iterator and transformer. If the given transformer is null, then objects will not be transformed.

Parameters:

iterator - the iterator to use

transformer - the transformer to use

Method Details

getIterator

public Iterator<? extends I> getIterator()

Gets the iterator this iterator is using.

Returns:

the iterator.

getTransformer

public Transformer<? super I,? extends O> getTransformer()

Gets the transformer this iterator is using.

Returns:

the transformer.

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<I>

next

public O next()

Gets the next object from the iteration, transforming it using the current transformer. If the transformer is null, no transformation occurs and the object from the iterator is returned directly.

Specified by:

next in interface Iterator<I>

Returns:

the next object

Throws:

NoSuchElementException - if there are no more elements

remove

public void remove()

Specified by:

remove in interface Iterator<I>

setIterator

public void setIterator(Iterator<? extends I> iterator)

Sets the iterator for this iterator to use. If iteration has started, this effectively resets the iterator.

Parameters:

iterator - the iterator to use

setTransformer

public void setTransformer(Transformer<? super I,? extends O> transformer)

Sets the transformer this the iterator to use. A null transformer is a no-op transformer.

Parameters:

transformer - the transformer to use

transform

protected O transform(I source)

Transforms the given object using the transformer. If the transformer is null, the original object is returned as-is.

Parameters:

source - the object to transform

Returns:

the transformed object