org.apache.xpath.axes
Class MatchPatternIterator

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.MatchPatternIterator
All Implemented Interfaces:
Cloneable, DTMIterator, ExpressionNode, PathComponent, Serializable, javax.xml.transform.SourceLocator, SubContextList, XPathVisitable

public class MatchPatternIterator
extends LocPathIterator

This class treats a LocationPath as a filtered iteration over the tree, evaluating each node in a super axis traversal against the LocationPath interpreted as a match pattern. This class is useful to find nodes in document order that are complex paths whose steps probably criss-cross each other.

See Also:
Serialized Form

Nested Class Summary
 
Nested classes inherited from class org.apache.xpath.axes.PredicatedNodeTest
PredicatedNodeTest.PredOwner
 
Field Summary
private static boolean DEBUG
          DEBUG flag for diagnostic dumps.
protected  StepPattern m_pattern
          This is the select pattern, translated into a match pattern.
protected  int m_superAxis
          The traversal axis from where the nodes will be filtered.
protected  DTMAxisTraverser m_traverser
          The DTM inner traversal class, that corresponds to the super axis.
 
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) MatchPatternIterator(Compiler compiler, int opPos, int analysis)
          Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.
 
Method Summary
 short acceptNode(int n, XPathContext xctxt)
          Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator.
protected  int getNextNode()
          Get the next node via getNextXXX.
 int nextNode()
          Returns the next node in the set and advances the position of the iterator in the set.
 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, callVisitors, cloneWithReset, detach, execute, executeCharsToContentHandler, getAnalysisBits, getAxis, getContext, getCurrentContextNode, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getFilter, getFoundLast, getIsTopLevel, getLastPos, getLength, getPrefixResolver, getRoot, getWhatToShow, getXPathContext, incrementCurrentPos, isDocOrdered, isFresh, isMutable, isNodesetExpr, item, previousNode, reset, returnNextNode, runTo, setCurrentContextNode, setCurrentPos, setEnvironment, setIsTopLevel, setItem, setNextPosition, setShouldCacheNodes, size
 
Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, countProximityPosition, deepEquals, executePredicates, fixupVariables, 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
 
Methods inherited from interface org.apache.xml.dtm.DTMIterator
clone
 

Field Detail

m_pattern

protected StepPattern m_pattern
This is the select pattern, translated into a match pattern.


m_superAxis

protected int m_superAxis
The traversal axis from where the nodes will be filtered.


m_traverser

protected DTMAxisTraverser m_traverser
The DTM inner traversal class, that corresponds to the super axis.


DEBUG

private static final boolean DEBUG
DEBUG flag for diagnostic dumps.

See Also:
Constant Field Values
Constructor Detail

MatchPatternIterator

MatchPatternIterator(Compiler compiler,
                     int opPos,
                     int analysis)
               throws javax.xml.transform.TransformerException
Create a LocPathIterator object, 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.
analysis - Analysis bits that give general information about the LocationPath.
Throws:
javax.xml.transform.TransformerException
Method Detail

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

getNextNode

protected int getNextNode()
Get the next node via getNextXXX. Bottlenecked for derived class override.

Returns:
The next node on the axis, or DTM.NULL.

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.

acceptNode

public short acceptNode(int n,
                        XPathContext xctxt)
Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator. This function will be called by the implementation of TreeWalker and NodeIterator; it is not intended to be called directly from user code.

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 .