org.apache.xpath.axes
Class WalkingIterator

java.lang.Object
  extended byorg.apache.xpath.Expression
      extended byorg.apache.xpath.patterns.NodeTest
          extended byorg.apache.xpath.axes.PredicatedNodeTest
              extended byorg.apache.xpath.axes.LocPathIterator
                  extended byorg.apache.xpath.axes.WalkingIterator
All Implemented Interfaces:
Cloneable, DTMIterator, ExpressionNode, ExpressionOwner, PathComponent, Serializable, javax.xml.transform.SourceLocator, SubContextList, 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 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.
 
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 class org.apache.xpath.Expression
 
Fields inherited from interface org.apache.xml.dtm.DTMIterator
FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP
 
Constructor Summary
(package private) 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.
 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(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, 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

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 Object clone()
             throws 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:
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,
                    Object environment)
Initialize the context values for this expression after it is cloned.

Specified by:
setRoot in interface DTMIterator
Overrides:
setRoot in class LocPathIterator

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(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
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
See Also:
Expression.deepEquals(Expression)