de.rwth.utils
Class AbstractIterator

java.lang.Object
  |
  +--de.rwth.utils.AbstractIterator

All Implemented Interfaces:

java.util.Iterator

public abstract class AbstractIterator

extends java.lang.Object

implements java.util.Iterator

Provides a default implementation for the Iterator interface. To get a working implementation of Iterator only the methods produceNext() and externalView(Object o) must be defined in a subclass.

This class allows to distinguish between internal (seen inside this class) and external representation (seen by the user of the Iterator).

Version:

$Id: AbstractIterator.java,v 1.2 2002/09/17 06:53:53 mohnen Exp $

Author:

Markus Mohnen

Constructor Summary

AbstractIterator()

Method Summary

abstract java.lang.Object	externalView(java.lang.Object o) The externalView method is supposed to convert internal to external representation.
boolean	hasNext()
java.lang.Object	next()
abstract java.lang.Object	produceNext() The produceNext method is supposed to produce the internal representation of the next element of the Iterator.
void	remove()

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractIterator

public AbstractIterator()

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator

next

public java.lang.Object next()
                      throws java.util.NoSuchElementException

Specified by:

next in interface java.util.Iterator

remove

public void remove()

Specified by:

remove in interface java.util.Iterator

produceNext

public abstract java.lang.Object produceNext()

The produceNext method is supposed to produce the internal representation of the next element of the Iterator. If there are no more elements, it should indicate this byte returning null. This method is guaranteed to be called exactly once to produce a new element, independently on how often hasNext() is called before a call to next().

Returns:

a value of type Object

externalView

public abstract java.lang.Object externalView(java.lang.Object o)

The externalView method is supposed to convert internal to external representation.

Parameters:

o - a value of type Object

Returns:

a value of type Object