org.apache.xpath.axes
Class UnionPathIterator

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.apache.xpath.patterns.NodeTest
              |
              +--org.apache.xpath.axes.PredicatedNodeTest
                    |
                    +--org.apache.xpath.axes.LocPathIterator
                          |
                          +--org.apache.xpath.axes.UnionPathIterator

public class UnionPathIterator
extends LocPathIterator
implements java.lang.Cloneable, DTMIterator, java.io.Serializable, PathComponent

This class extends NodeSetDTM, which implements DTMIterator, and fetches nodes one at a time in document order based on a XPath UnionExpr. As each node is iterated via nextNode(), the node is also stored in the NodeVector, so that previousNode() can easily be done.

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

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
 
Constructor Summary
UnionPathIterator()
          Constructor to create an instance which you can add location paths to.
UnionPathIterator(Compiler compiler, int opPos)
          Create a UnionPathIterator object, including creation of location path iterators from the opcode list, and call back into the Compiler to create predicate expressions.
 
Method Summary
 void addIterator(DTMIterator expr)
          Add an iterator to the union list.
 void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
           
 java.lang.Object clone()
          Get a cloned LocPathIterator that holds the same position as this iterator.
static LocPathIterator createUnionIterator(Compiler compiler, int opPos)
          This will return an iterator capable of handling the union of paths given.
 boolean deepEquals(Expression expr)
           
 void detach()
          Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
 void fixupVariables(java.util.Vector vars, int globalsSize)
          This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
 int getAnalysisBits()
          Get the analysis bits for this walker, as defined in the WalkerFactory.
 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, asNode, bool, cloneWithReset, execute, executeCharsToContentHandler, 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, 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
 

Constructor Detail

UnionPathIterator

public UnionPathIterator()
Constructor to create an instance which you can add location paths to.

UnionPathIterator

public UnionPathIterator(Compiler compiler,
                         int opPos)
                  throws TransformerException
Create a UnionPathIterator object, including creation of location path iterators from the opcode list, and call back into the Compiler to create predicate expressions.
Parameters:
compiler - The Compiler which is creating this expression.
opPos - The position of this iterator in the opcode list from the compiler.
Throws:
TransformerException -  
Method Detail

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
Parameters:
context - The XPath runtime context for this transformation.
Overrides:
setRoot in class LocPathIterator

addIterator

public void addIterator(DTMIterator expr)
Add an iterator to the union list.
Parameters:
expr - non-null reference to a location path iterator.

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

createUnionIterator

public static LocPathIterator createUnionIterator(Compiler compiler,
                                                  int opPos)
                                           throws TransformerException
This will return an iterator capable of handling the union of paths given.
Parameters:
compiler - The Compiler which is creating this expression.
opPos - The position of this iterator in the opcode list from the compiler.
Returns:
Object that is derived from LocPathIterator.
Throws:
TransformerException -  

getAnalysisBits

public int getAnalysisBits()
Get the analysis bits for this walker, as defined in the WalkerFactory.
Specified by:
getAnalysisBits in interface PathComponent
Returns:
One of WalkerFactory#BIT_DESCENDANT, etc.
Overrides:
getAnalysisBits in class LocPathIterator

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException
Get a cloned LocPathIterator that holds the same position as this iterator.
Specified by:
clone in interface DTMIterator
Returns:
A clone of this iterator that holds the same node position.
Throws:
java.lang.CloneNotSupportedException -  
Overrides:
clone in class PredicatedNodeTest

nextNode

public int nextNode()
Returns the next node in the set and advances the position of the iterator in the set. After a DTMIterator is created, the first call to nextNode() returns the first node in the set.
Specified by:
nextNode in interface DTMIterator
Returns:
The next Node in the set being iterated over, or null if there are no more members in that set.
Overrides:
nextNode in class LocPathIterator

fixupVariables

public void fixupVariables(java.util.Vector vars,
                           int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
Parameters:
vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame).
Overrides:
fixupVariables in class PredicatedNodeTest

getAxis

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

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)
Overrides:
callVisitors in class LocPathIterator
See Also:
XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)

deepEquals

public boolean deepEquals(Expression expr)
Overrides:
deepEquals in class PredicatedNodeTest
See Also:
Expression.deepEquals(Expression)


Copyright 2006 Apache XML Project. All Rights Reserved.