org.basex.query.iter

Class NodeCache

java.lang.Object

org.basex.query.iter.Iter

org.basex.query.iter.NodeIter

org.basex.query.iter.AxisIter

org.basex.query.iter.NodeCache

All Implemented Interfaces:

java.lang.Iterable<ANode>

public final class NodeCache
extends AxisIter

Caching node iterator, returning sorted nodes.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Field Summary

Fields

Modifier and Type	Field and Description
ANode[]	item Node container.

Constructor Summary

Constructors

Constructor and Description
NodeCache() Constructor.
NodeCache(ANode[] it, int s) Constructor, specifying an initial array of sorted nodes.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(ANode n) Adds a node.
int	binarySearch(DBNode nd, int start, int length) Performs a binary search on the given range of this sequence iterator, assuming that all nodes are DBNodes from the same Data instance (i.e., dbnodes() returns true).
boolean	dbnodes() Checks if binary search can be applied to this iterator, i.e.
void	delete(int p) Deletes a value at the specified position.
ANode	get(int i) Returns the specified node.
ANode	get(long i) Returns the specified item, or an arbitrary item if the index is invalid.
int	indexOf(ANode node, boolean db) Checks if the iterator contains a database node with the specified pre value.
ANode	next() Returns the next item or null if no other items are found.
NodeCache	random() Sets the internal duplicate flag, which indicates that duplicate and unordered nodes might be added to this iterator.
boolean	reset() Resets the iterator and returns true if operation was successful.
long	size() Returns the iterator size.
void	size(int s) Sets a new item size.
NodeCache	sort() Sorts the nodes, if necessary.
java.lang.String	toString()
Value	value() Returns a sequence with all iterator values.

Methods inherited from class org.basex.query.iter.AxisIter

iterator

Methods inherited from class java.lang.Object

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

Field Detail

item

public ANode[] item

Node container.

Constructor Detail

NodeCache

public NodeCache()

Constructor.

NodeCache

public NodeCache(ANode[] it,
         int s)

Constructor, specifying an initial array of sorted nodes.

Parameters:

it - node array

s - size

Method Detail

random

public NodeCache random()

Sets the internal duplicate flag, which indicates that duplicate and unordered nodes might be added to this iterator.

Returns:

self reference

get

public ANode get(int i)

Returns the specified node.

Parameters:

i - node offset

Returns:

node

delete

public void delete(int p)

Deletes a value at the specified position.

Parameters:

p - deletion position

add

public void add(ANode n)

Adds a node.

Parameters:

n - node to be added

reset

public 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

next

public ANode next()

Description copied from class: Iter

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

Specified by:

next in class AxisIter

Returns:

resulting item or null

get

public ANode 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 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

size

public void size(int s)

Sets a new item size.

Parameters:

s - size

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

dbnodes

public boolean dbnodes()

Checks if binary search can be applied to this iterator, i.e. if all nodes are DBNode references and refer to the same database.

Returns:

result of check

indexOf

public int indexOf(ANode node,
          boolean db)

Checks if the iterator contains a database node with the specified pre value.

Parameters:

node - node to be found

db - indicates if all nodes are sorted DBNode references

Returns:

position, or -1

binarySearch

public int binarySearch(DBNode nd,
               int start,
               int length)

Performs a binary search on the given range of this sequence iterator, assuming that all nodes are DBNodes from the same Data instance (i.e., dbnodes() returns true).

Parameters:

nd - node to find

start - start of the search interval

length - length of the search interval

Returns:

position of the item or -insertPosition - 1 if not found

sort

public NodeCache sort()

Sorts the nodes, if necessary.

Returns:

self reference

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object