org.apache.commons.collections.iterators

Class FilterIterator

Implemented Interfaces:
Iterator
Known Direct Subclasses:
UniqueFilterIterator

public class FilterIterator
extends java.lang.Object
implements Iterator

Decorates an iterator such that only elements matching a predicate filter are returned.
Version:
$Revision: 1.8 $ $Date: 2004/02/18 00:59:50 $
Authors:
James Strachan
Jan Sorensen
Ralph Wagner
Stephen Colebourne
Since:
Commons Collections 1.0

Constructor Summary

FilterIterator()
Constructs a new FilterIterator that will not function until setIterator is invoked.
FilterIterator(Iterator iterator)
Constructs a new FilterIterator that will not function until setPredicate is invoked.
FilterIterator(Iterator iterator, Predicate predicate)
Constructs a new FilterIterator that will use the given iterator and predicate.

Method Summary

Iterator
getIterator()
Gets the iterator this iterator is using.
Predicate
getPredicate()
Gets the predicate this iterator is using.
boolean
hasNext()
Returns true if the underlying iterator contains an object that matches the predicate.
Object
next()
Returns the next object that matches the predicate.
void
remove()
Removes from the underlying collection of the base iterator the last element returned by this iterator.
void
setIterator(Iterator iterator)
Sets the iterator for this iterator to use.
void
setPredicate(Predicate predicate)
Sets the predicate this the iterator to use.

Constructor Details

FilterIterator

public FilterIterator()

FilterIterator

public FilterIterator(Iterator iterator)
Parameters:
iterator - the iterator to use

FilterIterator

public FilterIterator(Iterator iterator,
                      Predicate predicate)
Constructs a new FilterIterator that will use the given iterator and predicate.
Parameters:
iterator - the iterator to use
predicate - the predicate to use

Method Details

getIterator

public Iterator getIterator()
Gets the iterator this iterator is using.
Returns:
the iterator.

getPredicate

public Predicate getPredicate()
Gets the predicate this iterator is using.
Returns:
the predicate.

hasNext

public boolean hasNext()
Returns true if the underlying iterator contains an object that matches the predicate.
Returns:
true if there is another object that matches the predicate

next

public Object next()
Returns the next object that matches the predicate.
Returns:
the next object which matches the given predicate

remove

public void remove()
Removes from the underlying collection of the base iterator the last element returned by this iterator. This method can only be called if next() was called, but not after hasNext(), because the hasNext() call changes the base iterator.

setIterator

public void setIterator(Iterator iterator)
Sets the iterator for this iterator to use. If iteration has started, this effectively resets the iterator.
Parameters:
iterator - the iterator to use

setPredicate

public void setPredicate(Predicate predicate)
Sets the predicate this the iterator to use.
Parameters:
predicate - the transformer to use

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