org.apache.xpath.axes
Class FilterExprWalker

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.apache.xpath.patterns.NodeTest
              |
              +--org.apache.xpath.axes.PredicatedNodeTest
                    |
                    +--org.apache.xpath.axes.AxesWalker
                          |
                          +--org.apache.xpath.axes.FilterExprWalker

public class FilterExprWalker
extends AxesWalker

Walker for the OP_VARIABLE, or OP_EXTFUNCTION, or OP_FUNCTION, or OP_GROUP, op codes.

See Also:
XPath FilterExpr descriptions, Serialized Form

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
FilterExprWalker(WalkingIterator locPathIterator)
          Construct a FilterExprWalker using a LocPathIterator.
 
Method Summary
 short acceptNode(int n)
          This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.
 void callPredicateVisitors(XPathVisitor visitor)
          This will traverse the heararchy, calling the visitor for each member.
 java.lang.Object clone()
          Get a cloned FilterExprWalker.
 boolean deepEquals(Expression expr)
           
 void detach()
          Detaches the walker 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.
 Expression getInnerExpression()
          Get the inner contained expression of this filter.
 int getLastPos(XPathContext xctxt)
          Get the index of the last node that can be itterated to.
 int getNextNode()
          Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node.
 void init(Compiler compiler, int opPos, int stepType)
          Init a FilterExprWalker.
 boolean isDocOrdered()
          Returns true if all the nodes in the iteration well be returned in document order.
 void setInnerExpression(Expression expr)
          Set the inner contained expression of this filter.
 void setRoot(int root)
          Set the root node of the TreeWalker.
 
Methods inherited from class org.apache.xpath.axes.AxesWalker
callVisitors, getCurrentNode, getDTM, getExpression, getNextWalker, getPrevWalker, getRoot, nextNode, setDefaultDTM, setExpression, setNextWalker, setPrevWalker, wi
 
Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
canTraverseOutsideSubtree, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, initProximityPosition, isReverseAxes, resetProximityPositions, setLocPathIterator, setPredicateCount
 
Methods inherited from class org.apache.xpath.patterns.NodeTest
debugWhatToShow, execute, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, getWhatToShow, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
 
Methods inherited from class org.apache.xpath.Expression
asIterator, asIteratorRaw, asNode, assertion, bool, error, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FilterExprWalker

public FilterExprWalker(WalkingIterator locPathIterator)
Construct a FilterExprWalker using a LocPathIterator.
Parameters:
locPathIterator - non-null reference to the parent iterator.
Method Detail

init

public void init(Compiler compiler,
                 int opPos,
                 int stepType)
          throws TransformerException
Init a FilterExprWalker.
Parameters:
compiler - non-null reference to the Compiler that is constructing.
opPos - positive opcode position for this step.
stepType - The type of step.
Throws:
TransformerException -  
Overrides:
init in class AxesWalker

detach

public void detach()
Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
Overrides:
detach in class AxesWalker

setRoot

public void setRoot(int root)
Set the root node of the TreeWalker.
Parameters:
root - non-null reference to the root, or starting point of the query.
Overrides:
setRoot in class AxesWalker

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException
Get a cloned FilterExprWalker.
Returns:
A new FilterExprWalker that can be used without mutating this one.
Throws:
java.lang.CloneNotSupportedException -  
Overrides:
clone in class AxesWalker

acceptNode

public short acceptNode(int n)
This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.
Parameters:
n - The node to check to see if it passes the filter or not.
Returns:
a constant to determine whether the node is accepted, rejected, or skipped, as defined above .
Overrides:
acceptNode in class PredicatedNodeTest

getNextNode

public int getNextNode()
Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returns null , and retains the current node.
Returns:
The new node, or null if the current node has no next node in the TreeWalker's logical view.

getLastPos

public int getLastPos(XPathContext xctxt)
Get the index of the last node that can be itterated to.
Parameters:
xctxt - XPath runtime context.
Returns:
the index of the last node that can be itterated to.
Overrides:
getLastPos in class AxesWalker

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

getInnerExpression

public Expression getInnerExpression()
Get the inner contained expression of this filter.

setInnerExpression

public void setInnerExpression(Expression expr)
Set the inner contained expression of this filter.

getAnalysisBits

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

isDocOrdered

public boolean isDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order. Warning: This can only be called after setRoot has been called!
Returns:
true as a default.
Overrides:
isDocOrdered in class AxesWalker

getAxis

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

callPredicateVisitors

public void callPredicateVisitors(XPathVisitor visitor)
This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.
Parameters:
visitor - The visitor whose appropriate method will be called.
Overrides:
callPredicateVisitors in class PredicatedNodeTest

deepEquals

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


Copyright 2006 Apache XML Project. All Rights Reserved.