org.apache.xpath.patterns

Class StepPattern

Implemented Interfaces:
ExpressionOwner, java.io.Serializable, ExpressionNode, SourceLocator, SubContextList, XPathVisitable
Known Direct Subclasses:
ContextMatchStepPattern, FunctionPattern

public class StepPattern
extends NodeTest
implements SubContextList, ExpressionOwner

This class represents a single pattern match step.

See Also:
Serialized Form

Field Summary

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

StepPattern(int whatToShow, String namespace, String name, int axis, int axisForPredicate)
Construct a StepPattern that tests for namespaces and node names.
StepPattern(int whatToShow, int axis, int axisForPredicate)
Construct a StepPattern that doesn't test for node names.

Method Summary

void
calcScore()
Static calc of match score.
void
calcTargetString()
Calculate the local name or psuedo name of the node that this pattern will test, for hash table lookup optimization.
void
callVisitors(ExpressionOwner owner, XPathVisitor visitor)
boolean
canTraverseOutsideSubtree()
Tell if this expression or it's subexpressions can traverse outside the current subtree.
boolean
deepEquals(Expression expr)
XObject
execute(XPathContext xctxt)
Execute this pattern step, including predicates.
XObject
execute(XPathContext xctxt, int currentNode)
Execute this pattern step, including predicates.
XObject
execute(XPathContext xctxt, int currentNode, DTM dtm, int expType)
Execute an expression in the XPath runtime context, and return the result of the expression.
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
getAxis()
Get the axis that this step follows.
Expression
getExpression()
int
getLastPos(XPathContext xctxt)
Get the count of the nodes that match the test, which is the proximity position of the last node that can pass this test in the sub context selection.
double
getMatchScore(XPathContext xctxt, int context)
Get the match score of the given node.
Expression
getPredicate(int i)
Get a predicate expression.
int
getPredicateCount()
Get the number of predicates for this match pattern step.
Expression[]
getPredicates()
Set the list of predicate expressions for this pattern step.
int
getProximityPosition(XPathContext xctxt)
Get the proximity position index of the current node based on this node test.
StepPattern
getRelativePathPattern()
Get the reference to nodetest and predicate for parent or ancestor.
String
getTargetString()
Get the local name or psuedo name of the node that this pattern will test, for hash table lookup optimization.
void
setAxis(int axis)
Set the axis that this step should follow.
void
setExpression(Expression exp)
void
setPredicates(Expression[] predicates)
Set the predicates for this match pattern step.
void
setRelativePathPattern(StepPattern expr)
Set the reference to nodetest and predicate for parent or ancestor.
String
toString()
Get the string represenentation of this step for diagnostic purposes.

Methods inherited from class org.apache.xpath.patterns.NodeTest

callVisitors, debugWhatToShow, deepEquals, execute, execute, execute, fixupVariables, 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, canTraverseOutsideSubtree, deepEquals, error, execute, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, fixupVariables, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr

Constructor Details

StepPattern

public StepPattern(int whatToShow,
                   String namespace,
                   String name,
                   int axis,
                   int axisForPredicate)
Construct a StepPattern that tests for namespaces and node names.

Parameters:
whatToShow - Bit set defined mainly by NodeFilter.
namespace - The namespace to be tested.
name - The local name to be tested.
axis - The Axis for this test, one of of Axes.ANCESTORORSELF, etc.
axisForPredicate - No longer used.


StepPattern

public StepPattern(int whatToShow,
                   int axis,
                   int axisForPredicate)
Construct a StepPattern that doesn't test for node names.

Parameters:
whatToShow - Bit set defined mainly by NodeFilter.
axis - The Axis for this test, one of of Axes.ANCESTORORSELF, etc.
axisForPredicate - No longer used.

Method Details

calcScore

public void calcScore()
Static calc of match score.


calcTargetString

public void calcTargetString()
Calculate the local name or psuedo name of the node that this pattern will test, for hash table lookup optimization.

See Also:
PsuedoNames


callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)
Specified by:
callVisitors in interface XPathVisitable
Overrides:
callVisitors in interface NodeTest

See Also:
XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)


canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()
Tell if this expression or it's subexpressions can traverse outside the current subtree. NOTE: Ancestors tests with predicates are problematic, and will require special treatment.
Overrides:
canTraverseOutsideSubtree in interface Expression

Returns:
true if traversal outside the context node's subtree can occur.


deepEquals

public boolean deepEquals(Expression expr)
Overrides:
deepEquals in interface NodeTest

See Also:
Expression.deepEquals(Expression)


execute

public XObject execute(XPathContext xctxt)
            throws TransformerException
Execute this pattern step, including predicates. NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.
Overrides:
execute in interface NodeTest

Parameters:
xctxt - XPath runtime context.

Returns:
NodeTest.SCORE_NODETEST,

Throws:
TransformerException -


execute

public XObject execute(XPathContext xctxt,
                       int currentNode)
            throws TransformerException
Execute this pattern step, including predicates. NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.
Overrides:
execute in interface NodeTest

Parameters:
xctxt - XPath runtime context.
currentNode - The current node context.

Returns:
NodeTest.SCORE_NODETEST,

Throws:
TransformerException -


execute

public XObject execute(XPathContext xctxt,
                       int currentNode,
                       DTM dtm,
                       int expType)
            throws TransformerException
Execute an expression in the XPath runtime context, and return the result of the expression.
Overrides:
execute in interface NodeTest

Parameters:
xctxt - The XPath runtime context.
currentNode - The currentNode.
dtm - The DTM of the current node.
expType - The expanded type ID of the current node.

Returns:
The result of the expression in the form of a XObject.

Throws:
TransformerException - if a runtime exception occurs.


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.
Overrides:
fixupVariables in interface NodeTest

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).
globalsSize - The number of variables in the global variable area.


getAxis

public int getAxis()
Get the axis that this step follows.

Returns:
The Axis for this test, one of of Axes.ANCESTORORSELF, etc.


getExpression

public Expression getExpression()
Specified by:
getExpression in interface ExpressionOwner

See Also:
ExpressionOwner.getExpression()


getLastPos

public int getLastPos(XPathContext xctxt)
Get the count of the nodes that match the test, which is the proximity position of the last node that can pass this test in the sub context selection. In XSLT 1-based indexing, this count is the index of the last node.
Specified by:
getLastPos in interface SubContextList

Parameters:
xctxt - XPath runtime context.

Returns:
the count of the nodes that match the test.


getMatchScore

public double getMatchScore(XPathContext xctxt,
                            int context)
            throws TransformerException

Parameters:
xctxt - The XPath runtime context.
context - The node to be tested.

Returns:
NodeTest.SCORE_NODETEST,

Throws:
TransformerException -


getPredicate

public Expression getPredicate(int i)
Get a predicate expression.

Parameters:
i - The index of the predicate.

Returns:
A predicate expression.


getPredicateCount

public final int getPredicateCount()
Get the number of predicates for this match pattern step.

Returns:
the number of predicates for this match pattern step.


getPredicates

public Expression[] getPredicates()
Set the list of predicate expressions for this pattern step.

Returns:
List of expression objects.


getProximityPosition

public int getProximityPosition(XPathContext xctxt)
Get the proximity position index of the current node based on this node test.
Specified by:
getProximityPosition in interface SubContextList

Parameters:
xctxt - XPath runtime context.

Returns:
the proximity position index of the current node based on the node test.


getRelativePathPattern

public StepPattern getRelativePathPattern()
Get the reference to nodetest and predicate for parent or ancestor.

Returns:
The relative pattern expression.


getTargetString

public String getTargetString()
Get the local name or psuedo name of the node that this pattern will test, for hash table lookup optimization.

Returns:
local name or psuedo name of the node.

See Also:
PsuedoNames


setAxis

public void setAxis(int axis)
Set the axis that this step should follow.

Parameters:
axis - The Axis for this test, one of of Axes.ANCESTORORSELF, etc.


setExpression

public void setExpression(Expression exp)
Specified by:
setExpression in interface ExpressionOwner

See Also:
ExpressionOwner.setExpression(Expression)


setPredicates

public void setPredicates(Expression[] predicates)
Set the predicates for this match pattern step.

Parameters:
predicates - An array of expressions that define predicates for this step.


setRelativePathPattern

public void setRelativePathPattern(StepPattern expr)
Set the reference to nodetest and predicate for parent or ancestor.

Parameters:
expr - The relative pattern expression.


toString

public String toString()
Get the string represenentation of this step for diagnostic purposes.

Returns:
A string representation of this step, built by reverse-engineering the contained info.


Copyright B) 2004 Apache XML Project. All Rights Reserved.