org.apache.xpath.patterns
Class StepPattern

java.lang.Object
  org.apache.xpath.Expression
      org.apache.xpath.patterns.NodeTest
          org.apache.xpath.patterns.StepPattern

All Implemented Interfaces:

ExpressionNode, ExpressionOwner, Serializable, javax.xml.transform.SourceLocator, SubContextList, XPathVisitable

Direct Known Subclasses:

ContextMatchStepPattern, FunctionPattern

public class StepPattern

extends NodeTest

implements SubContextList, ExpressionOwner

This class represents a single pattern match step.

See Also:

Serialized Form

Nested Class Summary

(package private) class

StepPattern.PredOwner

Field Summary

private static boolean	DEBUG_MATCHES Set to true to send diagnostics about pattern matches to the consol.
protected int	m_axis The axis for this test.
(package private) Expression[]	m_predicates The list of predicate expressions for this pattern step.
(package private) StepPattern	m_relativePathPattern Reference to nodetest and predicate for parent or ancestor.
(package private) String	m_targetString The target local name or psuedo name, for hash table lookup optimization.

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

m_name, m_namespace, m_score, m_whatToShow, SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, SUPPORTS_PRE_STRIPPING, WILD

Fields inherited from class org.apache.xpath.Expression

Constructor Summary

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

StepPattern(int whatToShow, String namespace, String name, int axis, int axisForPredicate)
Construct a StepPattern that tests for namespaces and 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.
protected void	callSubtreeVisitors(XPathVisitor visitor) Call the visitors on the subtree.
void	callVisitors(ExpressionOwner owner, XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
private boolean	checkProximityPosition(XPathContext xctxt, int predPos, DTM dtm, int context, int pos) New Method to check whether the current node satisfies a position predicate
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
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.
protected boolean	executePredicates(XPathContext xctxt, DTM dtm, int currentNode) Execute the predicates on this step to determine if the current node should be filtered or accepted.
protected XObject	executeRelativePathPattern(XPathContext xctxt, DTM dtm, int currentNode) Execute the match pattern step relative to another step.
void	fixupVariables(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() Get the raw Expression object that this class wraps.
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.
private int	getProximityPosition(XPathContext xctxt, int predPos, boolean findLast) 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) Set the raw expression object for this object.
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

debugWhatToShow, 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, isSameClass, isStableNumber, num, warn, xstr

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

m_axis

protected int m_axis

The axis for this test.

m_targetString

String m_targetString

The target local name or psuedo name, for hash table lookup optimization.

m_relativePathPattern

StepPattern m_relativePathPattern

Reference to nodetest and predicate for parent or ancestor.

m_predicates

Expression[] m_predicates

The list of predicate expressions for this pattern step.

DEBUG_MATCHES

private static final boolean DEBUG_MATCHES

Set to true to send diagnostics about pattern matches to the consol.

See Also:

Constant Field Values

Constructor Detail

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 Detail

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

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

fixupVariables

public void fixupVariables(Vector vars,
                           int globalsSize)

This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.

Overrides:

fixupVariables in class 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.

setRelativePathPattern

public void setRelativePathPattern(StepPattern expr)

Set the reference to nodetest and predicate for parent or ancestor.

Parameters:

expr - The relative pattern expression.

getRelativePathPattern

public StepPattern getRelativePathPattern()

Get the reference to nodetest and predicate for parent or ancestor.

Returns:

The relative pattern expression.

getPredicates

public Expression[] getPredicates()

Set the list of predicate expressions for this pattern step.

Returns:

List of expression objects.

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 class Expression

Returns:

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

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.

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.

calcScore

public void calcScore()

Static calc of match score.

Overrides:

calcScore in class NodeTest

execute

public XObject execute(XPathContext xctxt,
                       int currentNode)
                throws javax.xml.transform.TransformerException

Execute this pattern step, including predicates.

Overrides:

execute in class NodeTest

Parameters:

xctxt - XPath runtime context.

currentNode - The current node context.

Returns:

NodeTest.SCORE_NODETEST, NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.

Throws:

javax.xml.transform.TransformerException

execute

public XObject execute(XPathContext xctxt)
                throws javax.xml.transform.TransformerException

Execute this pattern step, including predicates.

Overrides:

execute in class NodeTest

Parameters:

xctxt - XPath runtime context.

Returns:

NodeTest.SCORE_NODETEST, NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.

Throws:

javax.xml.transform.TransformerException

execute

public XObject execute(XPathContext xctxt,
                       int currentNode,
                       DTM dtm,
                       int expType)
                throws javax.xml.transform.TransformerException

Execute an expression in the XPath runtime context, and return the result of the expression.

Overrides:

execute in class 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:

javax.xml.transform.TransformerException - if a runtime exception occurs.

checkProximityPosition

private final boolean checkProximityPosition(XPathContext xctxt,
                                             int predPos,
                                             DTM dtm,
                                             int context,
                                             int pos)

New Method to check whether the current node satisfies a position predicate

Parameters:

xctxt - The XPath runtime context.

predPos - Which predicate we're evaluating of foo[1][2][3].

dtm - The DTM of the current node.

context - The currentNode.

pos - The position being requested, i.e. the value returned by m_predicates[predPos].execute(xctxt).

Returns:

true of the position of the context matches pos, false otherwise.

getProximityPosition

private final int getProximityPosition(XPathContext xctxt,
                                       int predPos,
                                       boolean findLast)

Get the proximity position index of the current node based on this node test.

Parameters:

xctxt - XPath runtime context.

predPos - Which predicate we're evaluating of foo[1][2][3].

findLast - If true, don't terminate when the context node is found.

Returns:

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

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.

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.

executeRelativePathPattern

protected final XObject executeRelativePathPattern(XPathContext xctxt,
                                                   DTM dtm,
                                                   int currentNode)
                                            throws javax.xml.transform.TransformerException

Execute the match pattern step relative to another step.

Parameters:

xctxt - The XPath runtime context.

dtm - The DTM of the current node.

currentNode - The current node context.

Returns:

NodeTest.SCORE_NODETEST, NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.

Throws:

javax.xml.transform.TransformerException

executePredicates

protected final boolean executePredicates(XPathContext xctxt,
                                          DTM dtm,
                                          int currentNode)
                                   throws javax.xml.transform.TransformerException

Execute the predicates on this step to determine if the current node should be filtered or accepted.

Parameters:

xctxt - The XPath runtime context.

dtm - The DTM of the current node.

currentNode - The current node context.

Returns:

true if the node should be accepted, false otherwise.

Throws:

javax.xml.transform.TransformerException

toString

public String toString()

Get the string represenentation of this step for diagnostic purposes.

Overrides:

toString in class Object

Returns:

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

getMatchScore

public double getMatchScore(XPathContext xctxt,
                            int context)
                     throws javax.xml.transform.TransformerException

Get the match score of the given node.

Parameters:

xctxt - The XPath runtime context.

context - The node to be tested.

Returns:

NodeTest.SCORE_NODETEST, NodeTest.SCORE_NONE, NodeTest.SCORE_NSWILD, NodeTest.SCORE_QNAME, or NodeTest.SCORE_OTHER.

Throws:

javax.xml.transform.TransformerException

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.

getAxis

public int getAxis()

Get the axis that this step follows.

Returns:

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

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)

Description copied from interface: XPathVisitable

This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Specified by:

callVisitors in interface XPathVisitable

Overrides:

callVisitors in class NodeTest

See Also:

XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)

callSubtreeVisitors

protected void callSubtreeVisitors(XPathVisitor visitor)

Call the visitors on the subtree. Factored out from callVisitors so it may be called by derived classes.

getExpression

public Expression getExpression()

Description copied from interface: ExpressionOwner

Get the raw Expression object that this class wraps.

Specified by:

getExpression in interface ExpressionOwner

Returns:

the raw Expression object, which should not normally be null.

See Also:

ExpressionOwner.getExpression()

setExpression

public void setExpression(Expression exp)

Description copied from interface: ExpressionOwner

Set the raw expression object for this object.

Specified by:

setExpression in interface ExpressionOwner

Parameters:

exp - the raw Expression object, which should not normally be null.

See Also:

ExpressionOwner.setExpression(Expression)

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 NodeTest

See Also:

Expression.deepEquals(Expression)