org.apache.xpath.axes
Class DescendantIterator

java.lang.Object
  extended by org.apache.xpath.Expression
      extended by org.apache.xpath.patterns.NodeTest
          extended by org.apache.xpath.axes.PredicatedNodeTest
              extended by org.apache.xpath.axes.LocPathIterator
                  extended by org.apache.xpath.axes.DescendantIterator
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, javax.xml.transform.SourceLocator, DTMIterator, PathComponent, SubContextList, ExpressionNode, XPathVisitable

public class DescendantIterator
extends LocPathIterator

This class implements an optimized iterator for descendant, descendant-or-self, or "//foo" patterns.

See Also:
LocPathIterator, Serialized Form
Usage:
**For advanced use only**

Field Summary
 
Fields inherited from class org.apache.xpath.axes.LocPathIterator
m_lastFetched
 
Fields inherited from class org.apache.xpath.patterns.NodeTest
SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, SUPPORTS_PRE_STRIPPING, WILD
 
Fields inherited from interface org.apache.xml.dtm.DTMIterator
FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP
 
Constructor Summary
DescendantIterator()
          Create a DescendantIterator object.
 
Method Summary
 int asNode(XPathContext xctxt)
          Return the first node out of the nodeset, if this expression is a nodeset expression.
 DTMIterator cloneWithReset()
          Get a cloned Iterator that is reset to the beginning of the query.
 boolean deepEquals(Expression expr)
          Compare this object with another object and see if they are equal, include the sub heararchy.
 void detach()
          Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
 int getAxis()
          Returns the axis being iterated, if it is known.
 int nextNode()
          Returns the next node in the set and advances the position of the iterator in the set.
 void setRoot(int context, java.lang.Object environment)
          Initialize the context values for this expression after it is cloned.
 
Methods inherited from class org.apache.xpath.axes.LocPathIterator
allowDetachToRelease, asIterator, bool, callVisitors, execute, executeCharsToContentHandler, getAnalysisBits, getContext, getCurrentContextNode, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getFilter, getFoundLast, getIsTopLevel, getLastPos, getLength, getPrefixResolver, getRoot, getWhatToShow, getXPathContext, incrementCurrentPos, isDocOrdered, isFresh, isMutable, isNodesetExpr, item, previousNode, reset, runTo, setCurrentContextNode, setCurrentPos, setEnvironment, setIsTopLevel, setItem, setShouldCacheNodes, size
 
Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, fixupVariables, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, initProximityPosition, isReverseAxes, resetProximityPositions, setLocPathIterator, setPredicateCount
 
Methods inherited from class org.apache.xpath.patterns.NodeTest
debugWhatToShow, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
 
Methods inherited from class org.apache.xpath.Expression
asIteratorRaw, assertion, error, execute, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.xml.dtm.DTMIterator
clone
 

Constructor Detail

DescendantIterator

public DescendantIterator()
Create a DescendantIterator object.

Method Detail

cloneWithReset

public DTMIterator cloneWithReset()
                           throws java.lang.CloneNotSupportedException
Get a cloned Iterator that is reset to the beginning of the query.

Specified by:
cloneWithReset in interface DTMIterator
Overrides:
cloneWithReset in class LocPathIterator
Returns:
A cloned NodeIterator set of the start of the query.
Throws:
java.lang.CloneNotSupportedException

nextNode

public int nextNode()
Returns the next node in the set and advances the position of the iterator in the set. After a NodeIterator is created, the first call to nextNode() returns the first node in the set.

Specified by:
nextNode in interface DTMIterator
Specified by:
nextNode in class LocPathIterator
Returns:
The next Node in the set being iterated over, or null if there are no more members in that set.
Throws:
DOMException - INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked.

setRoot

public void setRoot(int context,
                    java.lang.Object environment)
Initialize the context values for this expression after it is cloned.

Specified by:
setRoot in interface DTMIterator
Overrides:
setRoot in class LocPathIterator
Parameters:
context - The XPath runtime context for this transformation.
environment - The environment object. The environment in which this iterator operates, which should provide:
  • a node (the context node... same value as "root" defined below)
  • a pair of non-zero positive integers (the context position and the context size)
  • a set of variable bindings
  • a function library
  • the set of namespace declarations in scope for the expression.
    • At this time the exact implementation of this environment is application dependent. Probably a proper interface will be created fairly soon.


asNode

public int asNode(XPathContext xctxt)
           throws javax.xml.transform.TransformerException
Return the first node out of the nodeset, if this expression is a nodeset expression. This is the default implementation for nodesets.

WARNING: Do not mutate this class from this function!

Overrides:
asNode in class LocPathIterator
Parameters:
xctxt - The XPath runtime context.
Returns:
the first node out of the nodeset, or DTM.NULL.
Throws:
javax.xml.transform.TransformerException

detach

public void detach()
Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. Afterdetach has been invoked, calls to nextNode orpreviousNode will raise the exception INVALID_STATE_ERR.

Specified by:
detach in interface DTMIterator
Overrides:
detach in class LocPathIterator

getAxis

public int getAxis()
Returns the axis being iterated, if it is known.

Specified by:
getAxis in interface DTMIterator
Overrides:
getAxis in class LocPathIterator
Returns:
Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.

deepEquals

public boolean deepEquals(Expression expr)
Description copied from class: Expression
Compare this object with another object and see if they are equal, include the sub heararchy.

Overrides:
deepEquals in class PredicatedNodeTest
Parameters:
expr - Another expression object.
Returns:
true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.
See Also:
Expression.deepEquals(Expression)


Copyright © 2005 Apache XML Project. All Rights Reserved.