org.apache.commons.collections.iterators

Class FilterListIterator

java.lang.Object

org.apache.commons.collections.iterators.FilterListIterator

All Implemented Interfaces:

java.util.Iterator, java.util.ListIterator

public class FilterListIterator
extends java.lang.Object
implements java.util.ListIterator

Decorates another ListIterator using a predicate to filter elements.

This iterator decorates the underlying iterator, only allowing through those elements that match the specified Predicate.

Since:

Commons Collections 2.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.ListIterator	iterator The iterator being used
private int	nextIndex The index of the element that would be returned by next().
private java.lang.Object	nextObject The value of the next (matching) object, when nextObjectSet is true.
private boolean	nextObjectSet Whether or not the nextObject has been set (possibly to null).
private Predicate	predicate The predicate being used
private java.lang.Object	previousObject The value of the previous (matching) object, when previousObjectSet is true.
private boolean	previousObjectSet Whether or not the previousObject has been set (possibly to null).

Constructor Summary

Constructors

Constructor and Description
FilterListIterator() Constructs a new FilterListIterator that will not function until setListIterator and setPredicate are invoked.
FilterListIterator(java.util.ListIterator iterator) Constructs a new FilterListIterator that will not function until setPredicate is invoked.
FilterListIterator(java.util.ListIterator iterator, Predicate predicate) Constructs a new FilterListIterator.
FilterListIterator(Predicate predicate) Constructs a new FilterListIterator that will not function until setListIterator is invoked.

Method Summary

Modifier and Type	Method and Description
void	add(java.lang.Object o) Not supported.
private void	clearNextObject()
private void	clearPreviousObject()
java.util.ListIterator	getListIterator() Gets the iterator this iterator is using.
Predicate	getPredicate() Gets the predicate this iterator is using.
boolean	hasNext()
boolean	hasPrevious()
java.lang.Object	next()
int	nextIndex()
java.lang.Object	previous()
int	previousIndex()
void	remove() Not supported.
void	set(java.lang.Object o) Not supported.
void	setListIterator(java.util.ListIterator iterator) Sets the iterator for this iterator to use.
private boolean	setNextObject()
void	setPredicate(Predicate predicate) Sets the predicate this the iterator to use.
private boolean	setPreviousObject()

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 Detail

iterator

private java.util.ListIterator iterator

The iterator being used

predicate

private Predicate predicate

The predicate being used

nextObject

private java.lang.Object nextObject

The value of the next (matching) object, when nextObjectSet is true.

nextObjectSet

private boolean nextObjectSet

Whether or not the nextObject has been set (possibly to null).

previousObject

private java.lang.Object previousObject

The value of the previous (matching) object, when previousObjectSet is true.

previousObjectSet

private boolean previousObjectSet

Whether or not the previousObject has been set (possibly to null).

nextIndex

private int nextIndex

The index of the element that would be returned by next().

Constructor Detail

FilterListIterator

public FilterListIterator()

Constructs a new FilterListIterator that will not function until setListIterator and setPredicate are invoked.

FilterListIterator

public FilterListIterator(java.util.ListIterator iterator)

Constructs a new FilterListIterator that will not function until setPredicate is invoked.

Parameters:

iterator - the iterator to use

FilterListIterator

public FilterListIterator(java.util.ListIterator iterator,
                          Predicate predicate)

Constructs a new FilterListIterator.

Parameters:

iterator - the iterator to use

predicate - the predicate to use

FilterListIterator

public FilterListIterator(Predicate predicate)

Constructs a new FilterListIterator that will not function until setListIterator is invoked.

Parameters:

predicate - the predicate to use.

Method Detail

add

public void add(java.lang.Object o)

Not supported.

Specified by:

add in interface java.util.ListIterator

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator

Specified by:

hasNext in interface java.util.ListIterator

hasPrevious

public boolean hasPrevious()

Specified by:

hasPrevious in interface java.util.ListIterator

next

public java.lang.Object next()

Specified by:

next in interface java.util.Iterator

Specified by:

next in interface java.util.ListIterator

nextIndex

public int nextIndex()

Specified by:

nextIndex in interface java.util.ListIterator

previous

public java.lang.Object previous()

Specified by:

previous in interface java.util.ListIterator

previousIndex

public int previousIndex()

Specified by:

previousIndex in interface java.util.ListIterator

remove

public void remove()

Not supported.

Specified by:

remove in interface java.util.Iterator

Specified by:

remove in interface java.util.ListIterator

set

public void set(java.lang.Object o)

Not supported.

Specified by:

set in interface java.util.ListIterator

getListIterator

public java.util.ListIterator getListIterator()

Gets the iterator this iterator is using.

Returns:

the iterator.

setListIterator

public void setListIterator(java.util.ListIterator iterator)

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

Parameters:

iterator - the iterator to use

getPredicate

public Predicate getPredicate()

Gets the predicate this iterator is using.

Returns:

the predicate.

setPredicate

public void setPredicate(Predicate predicate)

Sets the predicate this the iterator to use.

Parameters:

predicate - the transformer to use

clearNextObject

private void clearNextObject()

setNextObject

private boolean setNextObject()

clearPreviousObject

private void clearPreviousObject()

setPreviousObject

private boolean setPreviousObject()