org.apache.xpath.axes
Class WalkingIterator

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.WalkingIterator

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, javax.xml.transform.SourceLocator, DTMIterator, PathComponent, SubContextList, ExpressionNode, ExpressionOwner, XPathVisitable

Direct Known Subclasses:

WalkingIteratorSorted

public class WalkingIterator
extends LocPathIterator
implements ExpressionOwner

Location path iterator that uses Walkers.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.xpath.axes.PredicatedNodeTest

PredicatedNodeTest.PredOwner

Field Summary

protected AxesWalker	m_firstWalker The head of the step walker list.
protected AxesWalker	m_lastUsedWalker The last used step walker in the walker list.
(package private) static long	serialVersionUID

Fields inherited from class org.apache.xpath.axes.LocPathIterator

m_allowDetach, m_cdtm, m_clones, m_context, m_currentContextNode, m_execContext, m_lastFetched, m_length, m_pos, m_stackFrame

Fields inherited from class org.apache.xpath.axes.PredicatedNodeTest

DEBUG_PREDICATECOUNTING, m_foundLast, m_lpi, m_predCount, m_predicateIndex, m_proximityPositions

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

m_name, m_whatToShow, 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

WalkingIterator(Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)
Create a WalkingIterator iterator, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.

WalkingIterator(PrefixResolver nscontext)
Create a WalkingIterator object.

Method Summary

void	callVisitors(ExpressionOwner owner, XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
java.lang.Object	clone() Get a cloned WalkingIterator that holds the same position as this iterator.
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.
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.
Expression	getExpression() Get the raw Expression object that this class wraps.
AxesWalker	getFirstWalker() Get the head of the walker list.
AxesWalker	getLastUsedWalker() Get the last used walker.
int	nextNode() Returns the next node in the set and advances the position of the iterator in the set.
void	reset() Reset the iterator.
void	setExpression(Expression exp) Set the raw expression object for this object.
void	setFirstWalker(AxesWalker walker) Set the head of the walker list.
void	setLastUsedWalker(AxesWalker walker) Set the last used walker.
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, getAxis, getContext, getCurrentContextNode, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getFilter, getFoundLast, getIsTopLevel, getLastPos, getLength, getPrefixResolver, getRoot, getWhatToShow, getXPathContext, incrementCurrentPos, isDocOrdered, isFresh, isMutable, isNodesetExpr, item, previousNode, returnNextNode, runTo, setCurrentContextNode, setCurrentPos, setEnvironment, setIsTopLevel, setItem, setNextPosition, setShouldCacheNodes, size

Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest

acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, countProximityPosition, executePredicates, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, isReverseAxes, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount

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

calcScore, 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, isSameClass, isStableNumber, num, warn, xstr

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

static final long serialVersionUID

See Also:

Constant Field Values

m_lastUsedWalker

protected AxesWalker m_lastUsedWalker

The last used step walker in the walker list.

m_firstWalker

protected AxesWalker m_firstWalker

The head of the step walker list.

Constructor Detail

WalkingIterator

WalkingIterator(Compiler compiler,
                int opPos,
                int analysis,
                boolean shouldLoadWalkers)
          throws javax.xml.transform.TransformerException

Create a WalkingIterator iterator, including creation of step walkers 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.

shouldLoadWalkers - True if walkers should be loaded, or false if this is a derived iterator and it doesn't wish to load child walkers.

Throws:

javax.xml.transform.TransformerException

WalkingIterator

public WalkingIterator(PrefixResolver nscontext)

Create a WalkingIterator object.

Parameters:

nscontext - The namespace context for this iterator, should be OK if null.

Method Detail

getAnalysisBits

public int getAnalysisBits()

Get the analysis bits for this walker, as defined in the WalkerFactory.

Specified by:

getAnalysisBits in interface PathComponent

Overrides:

getAnalysisBits in class LocPathIterator

Returns:

One of WalkerFactory#BIT_DESCENDANT, etc.

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Get a cloned WalkingIterator that holds the same position as this iterator.

Specified by:

clone in interface DTMIterator

Overrides:

clone in class PredicatedNodeTest

Returns:

A clone of this iterator that holds the same node position.

Throws:

java.lang.CloneNotSupportedException

reset

public void reset()

Reset the iterator.

Specified by:

reset in interface DTMIterator

Overrides:

reset in class LocPathIterator

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.

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.

getFirstWalker

public final AxesWalker getFirstWalker()

Get the head of the walker list.

Returns:

The head of the walker list, or null if this iterator does not implement walkers.

setFirstWalker

public final void setFirstWalker(AxesWalker walker)

Set the head of the walker list.

Parameters:

walker - Should be a valid AxesWalker.

setLastUsedWalker

public final void setLastUsedWalker(AxesWalker walker)

Set the last used walker.

Parameters:

walker - The last used walker, or null.

getLastUsedWalker

public final AxesWalker getLastUsedWalker()

Get the last used walker.

Returns:

The last used walker, or null.

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

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 class PredicatedNodeTest

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).

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 LocPathIterator

Parameters:

owner - The owner of the visitor, where that path may be rewritten if needed.

visitor - The visitor whose appropriate method will be called.

See Also:

XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)

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 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)