Package com.twelvemonkeys.util

Class FilterIterator<E>

java.lang.Object

com.twelvemonkeys.util.FilterIterator<E>

All Implemented Interfaces:

Iterator<E>

public class FilterIterator<E>
extends Object
implements Iterator<E>

Wraps (decorates) an Iterator with extra functionality, to allow element filtering. Each element is filtered against the given Filter, and only elements that are accepted are returned by the next method.

The optional remove operation is implemented, but may throw UnsupportedOperationException if the underlying iterator does not support the remove operation.

Version:

$Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/util/FilterIterator.java#1 $

See Also:

• FilterIterator.Filter

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	FilterIterator.Filter<E>	Used to tests whether or not an element fulfills certain criteria, and hence should be accepted by the FilterIterator instance.

Field Summary

Fields

Modifier and Type	Field	Description
private E	current
protected final FilterIterator.Filter<E>	filter
protected final Iterator<E>	iterator
private E	next

Constructor Summary

Constructors

Constructor	Description
FilterIterator(Iterator<E> pIterator, FilterIterator.Filter<E> pFilter)	Creates a FilterIterator that wraps the Iterator.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Returns true if the iteration has more elements.
E	next()	Returns the next element in the iteration.
void	remove()	Removes from the underlying collection the last element returned by the iterator (optional operation).

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

Field Details

filter

protected final FilterIterator.Filter<E> filter

iterator

protected final Iterator<E> iterator

next

private E next

current

private E current

Constructor Details

FilterIterator

public FilterIterator(Iterator<E> pIterator,
 FilterIterator.Filter<E> pFilter)

Creates a FilterIterator that wraps the Iterator. Each element is filtered against the given Filter, and only elements that are accepted are returned by the next method.

Parameters:

pIterator - the iterator to filter

pFilter - the filter

See Also:

• FilterIterator.Filter

Method Details

hasNext

public boolean hasNext()

Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)

Specified by:

hasNext in interface Iterator<E>

Returns:

true if the iterator has more elements.

See Also:

• FilterIterator.Filter.accept(E)

next

public E next()

Returns the next element in the iteration.

Specified by:

next in interface Iterator<E>

Returns:

the next element in the iteration.

See Also:

• FilterIterator.Filter.accept(E)

remove

public void remove()

Removes from the underlying collection the last element returned by the iterator (optional operation). This method can be called only once per call to next. The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method.

Specified by:

remove in interface Iterator<E>