Class LocPathIterator
- 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.LocPathIterator
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,javax.xml.transform.SourceLocator
,DTMIterator
,PathComponent
,SubContextList
,ExpressionNode
,XPathVisitable
- Direct Known Subclasses:
BasicTestIterator
,ChildIterator
,DescendantIterator
,FilterExprIteratorSimple
,MatchPatternIterator
,SelfIteratorNoPredicate
,UnionPathIterator
,WalkingIterator
public abstract class LocPathIterator extends PredicatedNodeTest implements java.lang.Cloneable, DTMIterator, java.io.Serializable, PathComponent
This class extends NodeSetDTM, which implements NodeIterator, and fetches nodes one at a time in document order based on a XPath- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description int
m_lastFetched
The last node that was fetched, usually by nextNode.-
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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Fields inherited from interface org.apache.xml.dtm.DTMIterator
FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
allowDetachToRelease(boolean allowRelease)
Specify if it's OK for detach to release the iterator for reuse.DTMIterator
asIterator(XPathContext xctxt, int contextNode)
Given an select expression and a context, evaluate the XPath and return the resulting iterator.int
asNode(XPathContext xctxt)
Return the first node out of the nodeset, if this expression is a nodeset expression.boolean
bool(XPathContext xctxt)
Evaluate this operation directly to a boolean.void
callVisitors(ExpressionOwner owner, XPathVisitor visitor)
This will traverse the heararchy, calling the visitor for each member.DTMIterator
cloneWithReset()
Get a cloned Iterator that is reset to the beginning of the query.void
detach()
Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.XObject
execute(XPathContext xctxt)
Execute this iterator, meaning create a clone that can store state, and initialize it for fast execution from the current runtime state.void
executeCharsToContentHandler(XPathContext xctxt, org.xml.sax.ContentHandler handler)
Execute an expression in the XPath runtime context, and return the result of the expression.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
getContext()
The node context for the iterator.int
getCurrentContextNode()
The node context from where the expression is being executed from (i.e. for current() support).int
getCurrentNode()
Return the last fetched node.int
getCurrentPos()
Get the current position, which is one less than the next nextNode() call will retrieve.DTM
getDTM(int nodeHandle)
Get an instance of a DTM that "owns" a node handle.DTMManager
getDTMManager()
Get an instance of the DTMManager.boolean
getExpandEntityReferences()
The value of this flag determines whether the children of entity reference nodes are visible to the iterator.DTMFilter
getFilter()
The filter used to screen nodes.boolean
getFoundLast()
Tells if we've found the last node yet.boolean
getIsTopLevel()
Get if this is an iterator at the upper level of the XPath.int
getLastPos(XPathContext xctxt)
Get the index of the last node that can be itterated to.int
getLength()
The number of nodes in the list.PrefixResolver
getPrefixResolver()
Return the saved reference to the prefix resolver that was in effect when this iterator was created.int
getRoot()
The root node of the Iterator, as specified when it was created.int
getWhatToShow()
This attribute determines which node types are presented via the iterator.XPathContext
getXPathContext()
The XPath execution context we are operating on.void
incrementCurrentPos()
Increment the current position in the node set.boolean
isDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order.boolean
isFresh()
Tells if this NodeSetDTM is "fresh", in other words, if the first nextNode() that is called will return the first node in the set.boolean
isMutable()
Tells if this iterator can have nodes added to it or set via thesetItem(int node, int index)
method.boolean
isNodesetExpr()
Tell if the expression is a nodeset expression.int
item(int index)
Returns theindex
th item in the collection.abstract int
nextNode()
Returns the next node in the set and advances the position of the iterator in the set.int
previousNode()
Returns the previous node in the set and moves the position of the iterator backwards in the set.void
reset()
Reset the iterator.void
runTo(int index)
If an index is requested, NodeSetDTM will call this method to run the iterator to the index.void
setCurrentContextNode(int n)
Set the current context node for this iterator.void
setCurrentPos(int i)
Set the current position in the node set.void
setEnvironment(java.lang.Object environment)
Set 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.void
setIsTopLevel(boolean b)
Set if this is an iterator at the upper level of the XPath.void
setItem(int node, int index)
Sets the node at the specified index of this vector to be the specified node.void
setRoot(int context, java.lang.Object environment)
Initialize the context values for this expression after it is cloned.void
setShouldCacheNodes(boolean b)
If setShouldCacheNodes(true) is called, then nodes will be cached.int
size()
Get the length of the cached nodes.-
Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, deepEquals, 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, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
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Methods inherited from class org.apache.xpath.Expression
asIteratorRaw, assertion, error, execute, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isStableNumber, num, warn, xstr
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Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.apache.xml.dtm.DTMIterator
clone
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Method Detail
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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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setEnvironment
public void setEnvironment(java.lang.Object environment)
Set 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.
- Parameters:
environment
- The environment object.
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getDTM
public DTM getDTM(int nodeHandle)
Get an instance of a DTM that "owns" a node handle. Since a node iterator may be passed without a DTMManager, this allows the caller to easily get the DTM using just the iterator.- Specified by:
getDTM
in interfaceDTMIterator
- Parameters:
nodeHandle
- the nodeHandle.- Returns:
- a non-null DTM reference.
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getDTMManager
public DTMManager getDTMManager()
Get an instance of the DTMManager. Since a node iterator may be passed without a DTMManager, this allows the caller to easily get the DTMManager using just the iterator.- Specified by:
getDTMManager
in interfaceDTMIterator
- Returns:
- a non-null DTMManager reference.
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execute
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
Execute this iterator, meaning create a clone that can store state, and initialize it for fast execution from the current runtime state. When this is called, no actual query from the current context node is performed.
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executeCharsToContentHandler
public void executeCharsToContentHandler(XPathContext xctxt, org.xml.sax.ContentHandler handler) throws javax.xml.transform.TransformerException, org.xml.sax.SAXException
Execute an expression in the XPath runtime context, and return the result of the expression.- Overrides:
executeCharsToContentHandler
in classExpression
- Parameters:
xctxt
- The XPath runtime context.handler
- The target content handler.- Throws:
javax.xml.transform.TransformerException
- if a runtime exception occurs.org.xml.sax.SAXException
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asIterator
public DTMIterator asIterator(XPathContext xctxt, int contextNode) throws javax.xml.transform.TransformerException
Given an select expression and a context, evaluate the XPath and return the resulting iterator.- Overrides:
asIterator
in classExpression
- Parameters:
xctxt
- The execution context.contextNode
- The node that "." expresses.- Returns:
- A valid DTMIterator.
- Throws:
TransformerException
- thrown if the active ProblemListener decides the error condition is severe enough to halt processing.javax.xml.transform.TransformerException
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isNodesetExpr
public boolean isNodesetExpr()
Tell if the expression is a nodeset expression.- Overrides:
isNodesetExpr
in classExpression
- Returns:
- true if the expression can be represented as a nodeset.
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asNode
public int asNode(XPathContext xctxt) throws javax.xml.transform.TransformerException
Return the first node out of the nodeset, if this expression is a nodeset expression. This is the default implementation for nodesets. Derived classes should try and override this and return a value without having to do a clone operation.- Overrides:
asNode
in classExpression
- Parameters:
xctxt
- The XPath runtime context.- Returns:
- the first node out of the nodeset, or DTM.NULL.
- Throws:
javax.xml.transform.TransformerException
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bool
public boolean bool(XPathContext xctxt) throws javax.xml.transform.TransformerException
Evaluate this operation directly to a boolean.- Overrides:
bool
in classExpression
- Parameters:
xctxt
- The runtime execution context.- Returns:
- The result of the operation as a boolean.
- Throws:
javax.xml.transform.TransformerException
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setIsTopLevel
public void setIsTopLevel(boolean b)
Set if this is an iterator at the upper level of the XPath.- Parameters:
b
- true if this location path is at the top level of the expression.
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getIsTopLevel
public boolean getIsTopLevel()
Get if this is an iterator at the upper level of the XPath.- Returns:
- true if this location path is at the top level of the expression.
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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 interfaceDTMIterator
- 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.
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getCurrentPos
public final int getCurrentPos()
Get the current position, which is one less than the next nextNode() call will retrieve. i.e. if you call getCurrentPos() and the return is 0, the next fetch will take place at index 1.- Specified by:
getCurrentPos
in interfaceDTMIterator
- Returns:
- A value greater than or equal to zero that indicates the next node position to fetch.
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setShouldCacheNodes
public void setShouldCacheNodes(boolean b)
If setShouldCacheNodes(true) is called, then nodes will be cached. They are not cached by default.- Specified by:
setShouldCacheNodes
in interfaceDTMIterator
- Parameters:
b
- True if this iterator should cache nodes.
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isMutable
public boolean isMutable()
Tells if this iterator can have nodes added to it or set via thesetItem(int node, int index)
method.- Specified by:
isMutable
in interfaceDTMIterator
- Returns:
- True if the nodelist can be mutated.
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setCurrentPos
public void setCurrentPos(int i)
Set the current position in the node set.- Specified by:
setCurrentPos
in interfaceDTMIterator
- Parameters:
i
- Must be a valid index greater than or equal to zero and less than m_cachedNodes.size().
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incrementCurrentPos
public void incrementCurrentPos()
Increment the current position in the node set.
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size
public int size()
Get the length of the cached nodes.Note: for the moment at least, this only returns the size of the nodes that have been fetched to date, it doesn't attempt to run to the end to make sure we have found everything. This should be reviewed.
- Returns:
- The size of the current cache list.
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item
public int item(int index)
Returns theindex
th item in the collection. Ifindex
is greater than or equal to the number of nodes in the list, this returnsnull
.- Specified by:
item
in interfaceDTMIterator
- Parameters:
index
- Index into the collection.- Returns:
- The node at the
index
th position in theNodeList
, ornull
if that is not a valid index.
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setItem
public void setItem(int node, int index)
Sets the node at the specified index of this vector to be the specified node. The previous component at that position is discarded.The index must be a value greater than or equal to 0 and less than the current size of the vector. The iterator must be in cached mode.
Meant to be used for sorted iterators.
- Specified by:
setItem
in interfaceDTMIterator
- Parameters:
node
- Node to setindex
- Index of where to set the node
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getLength
public int getLength()
The number of nodes in the list. The range of valid child node indices is 0 tolength-1
inclusive.- Specified by:
getLength
in interfaceDTMIterator
- Returns:
- The number of nodes in the list, always greater or equal to zero.
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isFresh
public boolean isFresh()
Tells if this NodeSetDTM is "fresh", in other words, if the first nextNode() that is called will return the first node in the set.- Specified by:
isFresh
in interfaceDTMIterator
- Returns:
- true of nextNode has not been called.
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previousNode
public int previousNode()
Returns the previous node in the set and moves the position of the iterator backwards in the set.- Specified by:
previousNode
in interfaceDTMIterator
- Returns:
- The previous
Node
in the set being iterated over, ornull
if there are no more members in that set.
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getWhatToShow
public int getWhatToShow()
This attribute determines which node types are presented via the iterator. The available set of constants is defined in theNodeFilter
interface.This is somewhat useless at this time, since it doesn't really return information that tells what this iterator will show. It is here only to fullfill the DOM NodeIterator interface.
- Specified by:
getWhatToShow
in interfaceDTMIterator
- Overrides:
getWhatToShow
in classNodeTest
- Returns:
- For now, always NodeFilter.SHOW_ALL & ~NodeFilter.SHOW_ENTITY_REFERENCE.
- See Also:
NodeIterator
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getFilter
public DTMFilter getFilter()
The filter used to screen nodes. Not used at this time, this is here only to fullfill the DOM NodeIterator interface.- Returns:
- Always null.
- See Also:
NodeIterator
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getRoot
public int getRoot()
The root node of the Iterator, as specified when it was created.- Specified by:
getRoot
in interfaceDTMIterator
- Returns:
- The "root" of this iterator, which, in XPath terms, is the node context for this iterator.
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getExpandEntityReferences
public boolean getExpandEntityReferences()
The value of this flag determines whether the children of entity reference nodes are visible to the iterator. If false, they will be skipped over.
To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the iterator. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false.- Specified by:
getExpandEntityReferences
in interfaceDTMIterator
- Returns:
- Always true, since entity reference nodes are not visible in the XPath model.
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allowDetachToRelease
public void allowDetachToRelease(boolean allowRelease)
Specify if it's OK for detach to release the iterator for reuse.- Specified by:
allowDetachToRelease
in interfaceDTMIterator
- Parameters:
allowRelease
- true if it is OK for detach to release this iterator for pooling.
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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 tonextNode
orpreviousNode
will raise the exception INVALID_STATE_ERR.- Specified by:
detach
in interfaceDTMIterator
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reset
public void reset()
Reset the iterator.- Specified by:
reset
in interfaceDTMIterator
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cloneWithReset
public DTMIterator cloneWithReset() throws java.lang.CloneNotSupportedException
Get a cloned Iterator that is reset to the beginning of the query.- Specified by:
cloneWithReset
in interfaceDTMIterator
- Returns:
- A cloned NodeIterator set of the start of the query.
- Throws:
java.lang.CloneNotSupportedException
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nextNode
public abstract 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 interfaceDTMIterator
- Returns:
- The next
Node
in the set being iterated over, ornull
if there are no more members in that set.
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getCurrentNode
public int getCurrentNode()
Return the last fetched node. Needed to support the UnionPathIterator.- Specified by:
getCurrentNode
in interfaceDTMIterator
- Returns:
- The last fetched node, or null if the last fetch was null.
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runTo
public void runTo(int index)
If an index is requested, NodeSetDTM will call this method to run the iterator to the index. By default this sets m_next to the index. If the index argument is -1, this signals that the iterator should be run to the end.- Specified by:
runTo
in interfaceDTMIterator
- Parameters:
index
- The index to run to, or -1 if the iterator should run to the end.
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getFoundLast
public final boolean getFoundLast()
Tells if we've found the last node yet.- Returns:
- true if the last nextNode returned null.
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getXPathContext
public final XPathContext getXPathContext()
The XPath execution context we are operating on.- Returns:
- XPath execution context this iterator is operating on, or null if setRoot has not been called.
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getContext
public final int getContext()
The node context for the iterator.- Returns:
- The node context, same as getRoot().
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getCurrentContextNode
public final int getCurrentContextNode()
The node context from where the expression is being executed from (i.e. for current() support).- Returns:
- The top-level node context of the entire expression.
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setCurrentContextNode
public final void setCurrentContextNode(int n)
Set the current context node for this iterator.- Parameters:
n
- Must be a non-null reference to the node context.
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getPrefixResolver
public final PrefixResolver getPrefixResolver()
Return the saved reference to the prefix resolver that was in effect when this iterator was created.- Returns:
- The prefix resolver or this iterator, which may be null.
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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 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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isDocOrdered
public boolean isDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order.- Specified by:
isDocOrdered
in interfaceDTMIterator
- Returns:
- true as a default.
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getAxis
public int getAxis()
Returns the axis being iterated, if it is known.- Specified by:
getAxis
in interfaceDTMIterator
- Returns:
- Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.
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getLastPos
public int getLastPos(XPathContext xctxt)
Description copied from class:PredicatedNodeTest
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.
- See Also:
PredicatedNodeTest.getLastPos(XPathContext)
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