org.basex.query.iter

Class ValueIter

java.lang.Object

org.basex.query.iter.Iter

org.basex.query.iter.ValueIter

All Implemented Interfaces:

java.lang.Iterable<Item>

Direct Known Subclasses:

ItemCache

public abstract class ValueIter
extends Iter
implements java.lang.Iterable<Item>

Value iterator interface, throwing no exceptions. This class also implements the Iterable interface, which is why all of its values can also be retrieved via enhanced for (for-each) loops. Note, however, that using the next() method will give you better performance.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Constructor Summary

Constructors

Constructor and Description
ValueIter()

Method Summary

Methods

Modifier and Type	Method and Description
abstract Item	get(long i) Returns the specified item, or an arbitrary item if the index is invalid.
java.util.Iterator<Item>	iterator()
abstract Item	next() Returns the next item or null if no other items are found.
abstract boolean	reset() Resets the iterator and returns true if operation was successful.
abstract long	size() Returns the iterator size.
Value	value() Returns a sequence with all iterator values.

Methods inherited from class java.lang.Object

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

Constructor Detail

ValueIter

public ValueIter()

Method Detail

next

public abstract Item next()

Description copied from class: Iter

Returns the next item or null if no other items are found.

Specified by:

next in class Iter

Returns:

resulting item or null

get

public abstract Item get(long i)

Description copied from class: Iter

Returns the specified item, or an arbitrary item if the index is invalid. This method needs to be implemented - and should only be called - if Iter.size() returns the correct number of results. A calling method should call Iter.reset() after the last items has been retrieved.

Overrides:

get in class Iter

Parameters:

i - value offset

Returns:

specified item

size

public abstract long size()

Description copied from class: Iter

Returns the iterator size. Note: -1 is returned if the result size is unknown. If this method is implemented by an iterator, Iter.get(long) needs to be implemented as well.

Overrides:

size in class Iter

Returns:

number of entries

reset

public abstract boolean reset()

Description copied from class: Iter

Resets the iterator and returns true if operation was successful. false is returned if the iterator cannot be reset.

Overrides:

reset in class Iter

Returns:

true if operator could be reset

value

public Value value()

Description copied from class: Iter

Returns a sequence with all iterator values. Must only be called if Iter.next() has not been called before.

Overrides:

value in class Iter

Returns:

sequence

iterator

public final java.util.Iterator<Item> iterator()

Specified by:

iterator in interface java.lang.Iterable<Item>