org.apache.jackrabbit.commons.iterator
Class RangeIteratorAdapter

java.lang.Object
  org.apache.jackrabbit.commons.iterator.RangeIteratorAdapter

All Implemented Interfaces:

Iterator, RangeIterator

Direct Known Subclasses:

FrozenNodeIteratorAdapter

public class RangeIteratorAdapter
extends Object
implements RangeIterator

Adapter for turning normal Iterators into RangeIterators. This helper class is used by the adapter classes in this package to implement the JCR iterator interfaces on top of normal Java iterators.

Field Summary

static RangeIterator

EMPTY Static instance of an empty RangeIterator.

Constructor Summary

RangeIteratorAdapter(Collection collection)
Creates a RangeIterator for the given collection.

RangeIteratorAdapter(Iterator iterator)
Creates an adapter for the given iterator of unknown size.

RangeIteratorAdapter(Iterator iterator, long size)
Creates an adapter for the given iterator of the given size.

Method Summary

long	getPosition() Returns the current position of the iterator.
long	getSize() Returns the size of the iterator.
boolean	hasNext() Checks if this iterator has more elements.
Object	next() Returns the next element in this iterator and advances the iterator position.
void	remove() Removes the previously retrieved element.
void	skip(long n) Skips the given number of elements.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static final RangeIterator EMPTY

Static instance of an empty RangeIterator.

Constructor Detail

RangeIteratorAdapter

public RangeIteratorAdapter(Iterator iterator,
                            long size)

Creates an adapter for the given iterator of the given size.

Parameters:

iterator - adapted iterator

size - size of the iterator, or -1 if unknown

RangeIteratorAdapter

public RangeIteratorAdapter(Iterator iterator)

Creates an adapter for the given iterator of unknown size.

Parameters:

iterator - adapted iterator

RangeIteratorAdapter

public RangeIteratorAdapter(Collection collection)

Creates a RangeIterator for the given collection.

Parameters:

collection - the collection to iterate

Method Detail

getPosition

public long getPosition()

Returns the current position of the iterator.

Specified by:

getPosition in interface RangeIterator

Returns:

iterator position

getSize

public long getSize()

Returns the size of the iterator.

Specified by:

getSize in interface RangeIterator

Returns:

iterator size, or -1 if unknown

skip

public void skip(long n)
          throws IllegalArgumentException,
                 NoSuchElementException

Skips the given number of elements.

Specified by:

skip in interface RangeIterator

Parameters:

n - number of elements to skip

Throws:

IllegalArgumentException - if n is negative

NoSuchElementException - if skipped past the last element

hasNext

public boolean hasNext()

Checks if this iterator has more elements. If there are no more elements and the size of the iterator is unknown, then the size is set to the current position.

Specified by:

hasNext in interface Iterator

Returns:

true if this iterator has more elements, false otherwise

next

public Object next()
            throws NoSuchElementException

Returns the next element in this iterator and advances the iterator position. If there are no more elements and the size of the iterator is unknown, then the size is set to the current position.

Specified by:

next in interface Iterator

Returns:

next element

Throws:

NoSuchElementException - if there are no more elements

remove

public void remove()
            throws UnsupportedOperationException,
                   IllegalStateException

Removes the previously retrieved element. Decreases the current position and size of this iterator.

Specified by:

remove in interface Iterator

Throws:

UnsupportedOperationException - if removes are not permitted

IllegalStateException - if there is no previous element to remove