org.exist.xquery.value
Class PreorderedValueSequence

java.lang.Object
  extended byorg.exist.xquery.value.AbstractSequence
      extended byorg.exist.xquery.value.PreorderedValueSequence
All Implemented Interfaces:
Sequence

public class PreorderedValueSequence
extends AbstractSequence

A sequence that sorts its items in the order specified by the order specs of an "order by" clause. Used by ForExpr. For better performance, the whole input sequence is sorted in one single step. However, this only works if every order expression returns a result of type node.

Author:
wolf

Field Summary
 
Fields inherited from interface org.exist.xquery.value.Sequence
EMPTY_SEQUENCE
 
Constructor Summary
PreorderedValueSequence(OrderSpec[] specs, Sequence input, int contextId)
           
 
Method Summary
 void add(Item item)
          Add an item to the current sequence.
 void clearContext(int contextId)
          For every item in the sequence, clear any context-dependant information that is stored during query processing.
 int getItemType()
          Return the primary type to which all items in this sequence belong.
 int getLength()
          Returns the number of items contained in the sequence.
 boolean hasOne()
          Returns whether the sequence has just one item or not.
 boolean isEmpty()
          Returns whether the sequence is empty or not.
 Item itemAt(int pos)
          Returns the item located at the specified position within this sequence.
 SequenceIterator iterate()
          Returns an iterator over all items in the sequence.
 void removeDuplicates()
          Explicitely remove all duplicate nodes from this sequence.
 NodeSet toNodeSet()
          Convert the sequence into a NodeSet.
 SequenceIterator unorderedIterator()
          Returns an iterator over all items in the sequence.
 
Methods inherited from class org.exist.xquery.value.AbstractSequence
addAll, conversionPreference, convertTo, effectiveBooleanValue, getCardinality, getDocumentSet, getStringValue, hasMany, isCached, isPersistentSet, setIsCached, setSelfAsContext, toJavaObject, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

PreorderedValueSequence

public PreorderedValueSequence(OrderSpec[] specs,
                               Sequence input,
                               int contextId)
                        throws XPathException
Method Detail

clearContext

public void clearContext(int contextId)
Description copied from interface: Sequence
For every item in the sequence, clear any context-dependant information that is stored during query processing. This feature is used for node sets, which may store information about their context node.

Specified by:
clearContext in interface Sequence
Overrides:
clearContext in class AbstractSequence

getItemType

public int getItemType()
Description copied from interface: Sequence
Return the primary type to which all items in this sequence belong. This is Type.NODE for node sets, Type.ITEM for other sequences with mixed items.

Specified by:
getItemType in interface Sequence
Specified by:
getItemType in class AbstractSequence

iterate

public SequenceIterator iterate()
                         throws XPathException
Description copied from interface: Sequence
Returns an iterator over all items in the sequence. The items are returned in document order where applicable.

Specified by:
iterate in interface Sequence
Specified by:
iterate in class AbstractSequence
Throws:
XPathException

unorderedIterator

public SequenceIterator unorderedIterator()
Description copied from interface: Sequence
Returns an iterator over all items in the sequence. The returned items may - but need not - to be in document order.

Specified by:
unorderedIterator in interface Sequence
Specified by:
unorderedIterator in class AbstractSequence

getLength

public int getLength()
Description copied from interface: Sequence
Returns the number of items contained in the sequence. Call this method only when necessary, since it can be resource consuming.

Specified by:
getLength in interface Sequence
Specified by:
getLength in class AbstractSequence

isEmpty

public boolean isEmpty()
Description copied from interface: Sequence
Returns whether the sequence is empty or not.

Specified by:
isEmpty in interface Sequence
Specified by:
isEmpty in class AbstractSequence

hasOne

public boolean hasOne()
Description copied from interface: Sequence
Returns whether the sequence has just one item or not.

Specified by:
hasOne in interface Sequence
Specified by:
hasOne in class AbstractSequence

add

public void add(Item item)
         throws XPathException
Description copied from interface: Sequence
Add an item to the current sequence. An XPathException may be thrown if the item's type is incompatible with this type of sequence (e.g. if the sequence is a node set). The sequence may or may not allow duplicate values.

Specified by:
add in interface Sequence
Specified by:
add in class AbstractSequence
Throws:
XPathException

itemAt

public Item itemAt(int pos)
Description copied from interface: Sequence
Returns the item located at the specified position within this sequence. Items are counted beginning at 0.

Specified by:
itemAt in interface Sequence
Specified by:
itemAt in class AbstractSequence

toNodeSet

public NodeSet toNodeSet()
                  throws XPathException
Description copied from interface: Sequence
Convert the sequence into a NodeSet. If the sequence contains items which are not nodes, an XPathException is thrown.

Throws:
XPathException - if the sequence contains items which are not nodes.

removeDuplicates

public void removeDuplicates()
Description copied from interface: Sequence
Explicitely remove all duplicate nodes from this sequence.



Copyright (C) Wolfgang Meier. All rights reserved.