Package org.apache.xpath.axes
Class AxesWalker
- java.lang.Object
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- org.apache.xpath.Expression
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- org.apache.xpath.patterns.NodeTest
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- org.apache.xpath.axes.PredicatedNodeTest
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- org.apache.xpath.axes.AxesWalker
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,javax.xml.transform.SourceLocator
,PathComponent
,SubContextList
,ExpressionNode
,ExpressionOwner
,XPathVisitable
- Direct Known Subclasses:
FilterExprWalker
,ReverseAxesWalker
public class AxesWalker extends PredicatedNodeTest implements java.lang.Cloneable, PathComponent, ExpressionOwner
Serves as common interface for axes Walkers, and stores common state variables.- See Also:
- Serialized Form
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Field Summary
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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
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Constructor Summary
Constructors Constructor Description AxesWalker(LocPathIterator locPathIterator, int axis)
Construct an AxesWalker using a LocPathIterator.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
callVisitors(ExpressionOwner owner, XPathVisitor visitor)
This will traverse the heararchy, calling the visitor for each member.java.lang.Object
clone()
Get a cloned AxesWalker.boolean
deepEquals(Expression expr)
Compare this object with another object and see if they are equal, include the sub heararchy.void
detach()
Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.int
getAnalysisBits()
Get the analysis bits for this walker, as defined in the WalkerFactory.int
getAxis()
Returns the axis being iterated, if it is known.int
getCurrentNode()
The node at which the TreeWalker is currently positioned.DTM
getDTM(int node)
Get the DTM for this walker.Expression
getExpression()
Get the raw Expression object that this class wraps.int
getLastPos(XPathContext xctxt)
Get the index of the last node that can be itterated to.AxesWalker
getNextWalker()
Get the next walker in the location step chain.AxesWalker
getPrevWalker()
Get the previous walker reference in the location step chain.int
getRoot()
The root node of the TreeWalker, as specified in setRoot(int root).void
init(Compiler compiler, int opPos, int stepType)
Initialize an AxesWalker during the parse of the XPath expression.boolean
isDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order.int
nextNode()
Moves theTreeWalker
to the next visible node in document order relative to the current node, and returns the new node.void
setDefaultDTM(DTM dtm)
Set the DTM for this walker.void
setExpression(Expression exp)
Set the raw expression object for this object.void
setNextWalker(AxesWalker walker)
Set the next walker in the location step chain.void
setPrevWalker(AxesWalker walker)
Set or clear the previous walker reference in the location step chain.void
setRoot(int root)
Set the root node of the TreeWalker.WalkingIterator
wi()
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Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, fixupVariables, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, initProximityPosition, isReverseAxes, resetProximityPositions, setLocPathIterator, setPredicateCount
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Methods inherited from class org.apache.xpath.patterns.NodeTest
debugWhatToShow, execute, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, getWhatToShow, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
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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, isStableNumber, num, warn, xstr
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Constructor Detail
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AxesWalker
public AxesWalker(LocPathIterator locPathIterator, int axis)
Construct an AxesWalker using a LocPathIterator.- Parameters:
locPathIterator
- non-null reference to the parent iterator.
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Method Detail
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wi
public final WalkingIterator wi()
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init
public void init(Compiler compiler, int opPos, int stepType) throws javax.xml.transform.TransformerException
Initialize an AxesWalker during the parse of the XPath expression.- Parameters:
compiler
- The Compiler object that has information about this walker in the op map.opPos
- The op code position of this location step.stepType
- The type of location step.- Throws:
javax.xml.transform.TransformerException
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clone
public java.lang.Object clone() throws java.lang.CloneNotSupportedException
Get a cloned AxesWalker.- Overrides:
clone
in classPredicatedNodeTest
- Returns:
- A new AxesWalker that can be used without mutating this one.
- Throws:
java.lang.CloneNotSupportedException
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detach
public void detach()
Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
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getRoot
public int getRoot()
The root node of the TreeWalker, as specified in setRoot(int root). Note that this may actually be below the current node.- Returns:
- The context node of the step.
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getAnalysisBits
public int getAnalysisBits()
Get the analysis bits for this walker, as defined in the WalkerFactory.- Specified by:
getAnalysisBits
in interfacePathComponent
- Returns:
- One of WalkerFactory#BIT_DESCENDANT, etc.
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setRoot
public void setRoot(int root)
Set the root node of the TreeWalker. (Not part of the DOM2 TreeWalker interface).- Parameters:
root
- The context node of this step.
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getCurrentNode
public final int getCurrentNode()
The node at which the TreeWalker is currently positioned.
The value must not be null. Alterations to the DOM tree may cause the current node to no longer be accepted by the TreeWalker's associated filter. currentNode may also be explicitly set to any node, whether or not it is within the subtree specified by the root node or would be accepted by the filter and whatToShow flags. Further traversal occurs relative to currentNode even if it is not part of the current view by applying the filters in the requested direction (not changing currentNode where no traversal is possible).- Returns:
- The node at which the TreeWalker is currently positioned, only null if setRoot has not yet been called.
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setNextWalker
public void setNextWalker(AxesWalker walker)
Set the next walker in the location step chain.- Parameters:
walker
- Reference to AxesWalker derivative, or may be null.
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getNextWalker
public AxesWalker getNextWalker()
Get the next walker in the location step chain.- Returns:
- Reference to AxesWalker derivative, or null.
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setPrevWalker
public void setPrevWalker(AxesWalker walker)
Set or clear the previous walker reference in the location step chain.- Parameters:
walker
- Reference to previous walker reference in the location step chain, or null.
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getPrevWalker
public AxesWalker getPrevWalker()
Get the previous walker reference in the location step chain.- Returns:
- Reference to previous walker reference in the location step chain, or null.
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nextNode
public int nextNode()
Moves theTreeWalker
to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returnsnull
, and retains the current node.- Returns:
- The new node, or
null
if the current node has no next node in the TreeWalker's logical view.
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getLastPos
public int getLastPos(XPathContext xctxt)
Get the index of the last node that can be itterated to.- Specified by:
getLastPos
in interfaceSubContextList
- Specified by:
getLastPos
in classPredicatedNodeTest
- Parameters:
xctxt
- XPath runtime context.- Returns:
- the index of the last node that can be itterated to.
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setDefaultDTM
public void setDefaultDTM(DTM dtm)
Set the DTM for this walker.- Parameters:
dtm
- Non-null reference to a DTM.
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getDTM
public DTM getDTM(int node)
Get the DTM for this walker.- Returns:
- Non-null reference to a DTM.
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isDocOrdered
public boolean isDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order. Warning: This can only be called after setRoot has been called!- Returns:
- true as a default.
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getAxis
public int getAxis()
Returns the axis being iterated, if it is known.- Returns:
- Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.
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callVisitors
public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
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 interfaceXPathVisitable
- Overrides:
callVisitors
in classNodeTest
- 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)
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getExpression
public Expression getExpression()
Description copied from interface:ExpressionOwner
Get the raw Expression object that this class wraps.- Specified by:
getExpression
in interfaceExpressionOwner
- Returns:
- the raw Expression object, which should not normally be null.
- See Also:
ExpressionOwner.getExpression()
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setExpression
public void setExpression(Expression exp)
Description copied from interface:ExpressionOwner
Set the raw expression object for this object.- Specified by:
setExpression
in interfaceExpressionOwner
- Parameters:
exp
- the raw Expression object, which should not normally be null.- See Also:
ExpressionOwner.setExpression(Expression)
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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 classPredicatedNodeTest
- 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)
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