de.unidu.is.util
Class AcceptFilterIterator

java.lang.Object
  de.unidu.is.util.AcceptFilterIterator

All Implemented Interfaces:

AcceptFilter, java.util.Iterator

public abstract class AcceptFilterIterator

extends java.lang.Object

implements java.util.Iterator, AcceptFilter

A iterator that filters another iterator. The method accept(Object) is called for every item in the another iterator to test if that object should be returned by this filter iterator.

Since:

2001-04-23

Version:

$Revision: 1.5 $, $Date: 2005/02/21 17:29:29 $

Author:

Henrik Nottelmann

Field Summary

protected boolean	called Indicates if next() has ever been called.
protected java.util.Iterator	iterator The iterator to be filtered.
protected java.lang.Object	next The next object to be returned.

Constructor Summary

AcceptFilterIterator()
Creates a new filter iterator which has to be initialised.

AcceptFilterIterator(java.util.Iterator iterator)
Creates a new filter iterator.

Method Summary

abstract boolean	accept(java.lang.Object object) Returns true if the specified object should be returned by next().
protected void	calcNext() Calculates the next object to be returned.
boolean	hasNext() Returns true if this iterator has more elements.
void	init(java.util.Iterator iterator) Inits this iterator.
java.lang.Object	next() Returns the next object.
void	remove() Removing objects is unsupported!

Methods inherited from class java.lang.Object

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

Field Detail

iterator

protected java.util.Iterator iterator

The iterator to be filtered.

next

protected java.lang.Object next

The next object to be returned.

called

protected boolean called

Indicates if next() has ever been called. This is needed for initialisation outside the constructor (because that does not work!).

Constructor Detail

AcceptFilterIterator

public AcceptFilterIterator()

Creates a new filter iterator which has to be initialised.

AcceptFilterIterator

public AcceptFilterIterator(java.util.Iterator iterator)

Creates a new filter iterator.

Parameters:

iterator - iterator to be filtered

Method Detail

init

public void init(java.util.Iterator iterator)

Inits this iterator.

Parameters:

iterator - iterator to be filtered

hasNext

public boolean hasNext()

Returns true if this iterator has more elements.

Specified by:

hasNext in interface java.util.Iterator

Returns:

true if the iterator has more elements

next

public java.lang.Object next()

Returns the next object.

Specified by:

next in interface java.util.Iterator

Returns:

next object

Throws:

java.util.NoSuchElementException - if there is no object available

calcNext

protected void calcNext()

Calculates the next object to be returned.

accept

public abstract boolean accept(java.lang.Object object)

Returns true if the specified object should be returned by next(). This method has to be overridden!

Specified by:

accept in interface AcceptFilter

Parameters:

object - object to be testet

Returns:

true if the specified object should be returned by next()

remove

public void remove()

Removing objects is unsupported!

Specified by:

remove in interface java.util.Iterator