net.sf.staccatocommons.iterators
Class UpdateCurrentThriterator<A>

java.lang.Object
  net.sf.staccatocommons.iterators.AbstractUnmodifiableIterator<A>
      net.sf.staccatocommons.iterators.thriter.AbstractThriterator<A>
          net.sf.staccatocommons.iterators.thriter.AdvanceThriterator<A>
              net.sf.staccatocommons.iterators.UpdateCurrentThriterator<A>

Type Parameters:

A -

All Implemented Interfaces:

Iterator<A>, EmptyAware, Thriter<A>, Thriterator<A>

public abstract class UpdateCurrentThriterator<A>
extends AdvanceThriterator<A>

A thriterator that is implemented through a single message updateCurrent(), which is both responsible for answering if there is a current element and setting it.

This is useful when implementor does not know if it has a next element until it effectively computes it. This implementation of Thriterator resolves it by caching the temporal element

Typical implementation of that method is the following:

 protected boolean updateCurrent() {
   A element = .. compute next element ..
   if ( .. element matches a criteria ..  ) {
     setCurrent(element);
   }
 }
 

Since:

2.2

Author:

flbulgarelli

Constructor Summary

UpdateCurrentThriterator()

Method Summary

void	advanceNext() Advances to the thriter to the position of the next element.
A	current() Answers element at the current position of this Thriter.
boolean	hasNext() Answers if the thriter has more elements, that is, if sending Thriter.advanceNext() would not result in a NoSuchElementException
protected void	setCurrent(A current) Sets the current value of iteration.
protected abstract void	updateCurrent() Sets the current element, if any.

Methods inherited from class net.sf.staccatocommons.iterators.thriter.AdvanceThriterator

next

Methods inherited from class net.sf.staccatocommons.iterators.thriter.AbstractThriterator

delayedCurrent, delayedNext, isEmpty

Methods inherited from class net.sf.staccatocommons.iterators.AbstractUnmodifiableIterator

remove

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

remove

Constructor Detail

UpdateCurrentThriterator

public UpdateCurrentThriterator()

Method Detail

hasNext

public final boolean hasNext()

Description copied from interface: Thriter

Answers if the thriter has more elements, that is, if sending Thriter.advanceNext() would not result in a NoSuchElementException

Returns:

if the Thriter has more elements

advanceNext

public final void advanceNext()
                       throws NoSuchElementException

Description copied from interface: Thriter

Advances to the thriter to the position of the next element.

Throws:

NoSuchElementException - if there are no more elements

setCurrent

protected final void setCurrent(A current)

Sets the current value of iteration.

Parameters:

current - the current value of iteration

current

public final A current()

Description copied from interface: Thriter

Answers element at the current position of this Thriter. Result of this method if Thriter.advanceNext() was never evaluated before is undefined.

Returns:

the current element

updateCurrent

protected abstract void updateCurrent()

Sets the current element, if any. Implementors need to send setCurrent(Object) in order to indicate which is the next element. If there is no current element - end of source has reached - implementors must do nothing.