com.bigdata.striterator

Class PushbackIterator<E>

java.lang.Object

com.bigdata.striterator.PushbackIterator<E>

Type Parameters:

E -

All Implemented Interfaces:

ICloseable, ICloseableIterator<E>, Iterator<E>

public class PushbackIterator<E>
extends Object
implements Iterator<E>, ICloseableIterator<E>

Allows pushback of the most recently visited element onto the iterator.

Note: There is no corresponding IFilter pattern for this class since you need the interface offered by the PushbackIterator in order to use pushback.

Version:

$Id$

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
PushbackIterator(Iterator<E> src)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the iterator, releasing any associated resources.
boolean	hasNext()
E	next()
void	pushback() Push the value onto the internal buffer.
void	remove()

Methods inherited from class java.lang.Object

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

Constructor Detail

PushbackIterator

public PushbackIterator(Iterator<E> src)

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<E>

next

public E next()

Specified by:

next in interface Iterator<E>

pushback

public void pushback()

Push the value onto the internal buffer. It will be returned by the next call to next().

Parameters:

value - The value.

Throws:

IllegalStateException - if there is already a value pushed back.

remove

public void remove()

Specified by:

remove in interface Iterator<E>

close

public void close()

Description copied from interface: ICloseableIterator

Closes the iterator, releasing any associated resources. This method MAY be invoked safely if the iterator is already closed. Implementations of this interface MUST invoke ICloseableIterator.close() if Iterator.hasNext() method returns false to ensure that the iterator is closed (and its resources release) as soon as it is exhausted.

Note: Implementations that support Iterator.remove() MUST NOT eagerly close the iterator when it is exhausted since that would make it impossible to remove the last visited statement. Instead they MUST wait for an explicit ICloseableIterator.close() by the application.

Specified by:

close in interface ICloseable

Specified by:

close in interface ICloseableIterator<E>