Class LocPathIterator
- All Implemented Interfaces:
Cloneable
,SourceLocator
,DTMIterator
,PathComponent
,SubContextList
,ExpressionNode
,XPathVisitable
- Direct Known Subclasses:
BasicTestIterator
,ChildIterator
,DescendantIterator
,SelfIteratorNoPredicate
,UnionPathIterator
,WalkingIterator
If setShouldCacheNodes(true) is called, as each node is iterated via nextNode(), the node is also stored in the NodeVector, so that previousNode() can easily be done, except in the case where the LocPathIterator is "owned" by a UnionPathIterator, in which case the UnionPathIterator will cache the nodes.
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Field Summary
Modifier and TypeFieldDescriptionprotected boolean
Control over whether it is OK for detach to reset the iterator.protected DTM
The dtm of the context node.protected final IteratorPool
The pool for cloned iterators.protected int
The context node for this iterator, which doesn't change through the course of the iteration.protected int
The node context from where the expression is being executed from (i.e. for current() support).protected XPathContext
The XPathContext reference, needed for execution of many operations.int
The last node that was fetched, usually by nextNode.protected int
protected int
The current position of the context node.Fields inherited from class org.loboevolution.apache.xpath.axes.PredicatedNodeTest
m_foundLast, m_lpi, m_predCount, m_proximityPositions
Fields inherited from class org.loboevolution.apache.xpath.patterns.NodeTest
m_name, m_whatToShow, SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, WILD
Fields inherited from interface org.loboevolution.apache.xml.dtm.DTMIterator
FILTER_ACCEPT, FILTER_SKIP
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Constructor Summary
ModifierConstructorDescriptionprotected
Create a LocPathIterator object.protected
LocPathIterator
(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.protected
LocPathIterator
(int analysis, boolean shouldLoadWalkers) Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.protected
LocPathIterator
(PrefixResolver nscontext) Create a LocPathIterator object. -
Method Summary
Modifier and TypeMethodDescriptionvoid
allowDetachToRelease
(boolean allowRelease) Specify if it's OK for detach to release the iterator for reuse.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 expression to a boolean.void
callVisitors
(XPathVisitor visitor) This will traverse the hierarchy, calling the visitor for each member.Get a cloned Iterator that is reset to the start of the iteration.void
detach()
Detaches theDTMIterator
from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.execute
(XPathContext xctxt) Execute an expression in the XPath runtime context, and return the result of the expression.int
Get the analysis bits for this path component, as defined in the WalkerFactory.int
getAxis()
Returns the axis being iterated, if it is known.int
Get the current node in the iterator.final int
Get the current position within the cached list, 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.getDTM
(int nodeHandle) Get an instance of a DTM that "owns" a node handle.Get an instance of the DTMManager.boolean
The value of this flag determines whether the children of entity reference nodes are visible to the iterator.boolean
Get if this is an iterator at the upper level of the XPath.int
getLastPos
(XPathContext xctxt) Get the number of nodes in the node list, which, in the XSLT 1 based counting system, is the last index position.int
The number of nodes in the list.final PrefixResolver
Return the saved reference to the prefix resolver that was in effect when this iterator was created.int
getRoot()
The root node of theDTMIterator
, as specified when it was created.int
This attribute determines which node types are accepted.final XPathContext
The XPath execution context we are operating on.void
Increment the current position in the node set.boolean
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.int
item
(int index) Returns thenode handle
of an 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
Returns the previous node in the set and moves the position of theDTMIterator
backwards in the set.void
reset()
Reset the iterator to the start.protected int
returnNextNode
(int nextNode) Bottleneck the return of a next node, to make returns easier from nextNode().void
runTo
(int index) If an index is requested, NodeSetDTM will call this method to run the iterator to the index.void
setCurrentPos
(int i) Set the current position in the node set.void
setIsTopLevel
(boolean b) Set if this is an iterator at the upper level of the XPath.void
Reset the root node of theDTMIterator
, overriding the value specified when it was created.void
setShouldCacheNodes
(boolean b) If setShouldCacheNodes(true) is called, then nodes will be cached, enabling random access, and giving the ability to do sorts and the like.Methods inherited from class org.loboevolution.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, countProximityPosition, deepEquals, getPredicate, getPredicateCount, getProximityPosition, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, isReverseAxes, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount
Methods inherited from class org.loboevolution.apache.xpath.patterns.NodeTest
calcScore, execute, execute, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
Methods inherited from class org.loboevolution.apache.xpath.Expression
assertion, error, execute, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isSameClass, isStableNumber, num
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.loboevolution.apache.xml.dtm.DTMIterator
clone
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Field Details
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m_allowDetach
protected boolean m_allowDetachControl over whether it is OK for detach to reset the iterator. -
m_clones
The pool for cloned iterators. Iterators need to be cloned because the hold running state, and thus the original iterator expression from the stylesheet pool can not be used. -
m_cdtm
The dtm of the context node. Careful about using this... it may not be the dtm of the current node. -
m_lastFetched
public transient int m_lastFetchedThe last node that was fetched, usually by nextNode. -
m_context
protected transient int m_contextThe context node for this iterator, which doesn't change through the course of the iteration. -
m_currentContextNode
protected transient int m_currentContextNodeThe node context from where the expression is being executed from (i.e. for current() support). Different from m_context in that this is the context for the entire expression, rather than the context for the subexpression. -
m_pos
protected transient int m_posThe current position of the context node. -
m_length
protected transient int m_length -
m_execContext
The XPathContext reference, needed for execution of many operations.
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Constructor Details
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LocPathIterator
protected LocPathIterator()Create a LocPathIterator object. -
LocPathIterator
Create a LocPathIterator object.- Parameters:
nscontext
- The namespace context for this iterator, should be OK if null.
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LocPathIterator
Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.- Throws:
TransformerException
- if any
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LocPathIterator
Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.- Parameters:
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:
TransformerException
- if any
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Method Details
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getAnalysisBits
public int getAnalysisBits()Get the analysis bits for this path component, as defined in the WalkerFactory.- Specified by:
getAnalysisBits
in interfacePathComponent
- Returns:
- One of WalkerFactory#BIT_DESCENDANT, etc.
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getDTM
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
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
Execute an expression in the XPath runtime context, and return the result of the expression.- Overrides:
execute
in classNodeTest
- Parameters:
xctxt
- The XPath runtime context.- Returns:
- The result of the expression in the form of a
XObject
. - Throws:
TransformerException
- if a runtime exception occurs.
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asIterator
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.
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asNode
Return the first node out of the nodeset, if this expression is a nodeset expression.- Overrides:
asNode
in classExpression
- Parameters:
xctxt
- The XPath runtime context.- Returns:
- the first node out of the nodeset, or DTM.NULL.
- Throws:
TransformerException
- if any
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bool
Evaluate expression to a boolean.- Overrides:
bool
in classExpression
- Parameters:
xctxt
- The XPath runtime context.- Returns:
- false
- Throws:
TransformerException
- if any
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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
Reset the root node of theDTMIterator
, overriding the value specified when it was created. Note the root node is not the root node of the document tree, but the context node from where the iteration begins.- Specified by:
setRoot
in interfaceDTMIterator
- Parameters:
context
- int Handle of the context node.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 within the cached list, 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:
- The position of the iteration.
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setShouldCacheNodes
public void setShouldCacheNodes(boolean b) If setShouldCacheNodes(true) is called, then nodes will be cached, enabling random access, and giving the ability to do sorts and the like. They are not cached by default.%REVIEW% Shouldn't the other random-access methods throw an exception if they're called on a DTMIterator with this flag set false?
- Specified by:
setShouldCacheNodes
in interfaceDTMIterator
- Parameters:
b
- true if the nodes should be cached.
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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.
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incrementCurrentPos
public void incrementCurrentPos()Increment the current position in the node set. -
item
public int item(int index) Returns thenode handle
of an 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
- of the item.- Returns:
- The node handle at the
index
th position in theDTMIterator
, or-1
if that is not a valid index.
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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. Note that this requires running the iterator to completion, and presumably filling the cache.- Specified by:
getLength
in interfaceDTMIterator
- Returns:
- The number of nodes in the list.
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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 if the iteration of this list has not yet begun.
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previousNode
public int previousNode()Returns the previous node in the set and moves the position of theDTMIterator
backwards in the set.- Specified by:
previousNode
in interfaceDTMIterator
- Returns:
- The previous node handle in the set being iterated over, or
DTM.NULL
if there are no more members in that set.
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getWhatToShow
public int getWhatToShow()This attribute determines which node types are accepted. These constants are defined in theNodeFilter
interface.- Specified by:
getWhatToShow
in interfaceDTMIterator
- Overrides:
getWhatToShow
in classNodeTest
- Returns:
- bitset mainly defined in
NodeFilter
.
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getRoot
public int getRoot()The root node of theDTMIterator
, as specified when it was created. Note the root node is not the root node of the document tree, but the context node from where the iteration begins and ends.- Specified by:
getRoot
in interfaceDTMIterator
- Returns:
- nodeHandle int Handle of the context node.
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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 and their descendants will be rejected. Note that this rejection takes precedence overwhatToShow
and the filter.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 setexpandEntityReferences
to true when creating the iterator. To produce a view of the document that has entity reference nodes but no entity expansion, use thewhatToShow
flags to show the entity reference node and setexpandEntityReferences
to false.NOTE: In Xalan's use of DTM we will generally have fully expanded entity references when the document tree was built, and thus this flag will have no effect.
- Specified by:
getExpandEntityReferences
in interfaceDTMIterator
- Returns:
- true if entity references will be expanded.
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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 theDTMIterator
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 a runtime exception.- Specified by:
detach
in interfaceDTMIterator
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reset
public void reset()Reset the iterator to the start. After resetting, the next node returned will be the root node -- or, if that's filtered out, the first node within the root's subtree which is _not_ skipped by the filters.- Specified by:
reset
in interfaceDTMIterator
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cloneWithReset
Get a cloned Iterator that is reset to the start of the iteration.- Specified by:
cloneWithReset
in interfaceDTMIterator
- Returns:
- A clone of this iteration that has been reset.
- Throws:
CloneNotSupportedException
- if any
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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 aDTMIterator
has setRoot called, the first call tonextNode()
returns that root or (if it is rejected by the filters) the first node within its subtree which is not filtered out.- Specified by:
nextNode
in interfaceDTMIterator
- Returns:
- The next node handle in the set being iterated over, or
DTM.NULL
if there are no more members in that set.
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returnNextNode
protected int returnNextNode(int nextNode) Bottleneck the return of a next node, to make returns easier from nextNode().- Parameters:
nextNode
- The next node found, may be null.- Returns:
- The same node that was passed as an argument.
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getCurrentNode
public int getCurrentNode()Get the current node in the iterator. Note that this differs from the DOM's NodeIterator, where the current position lies between two nodes (as part of the maintain-relative-position semantic).- Specified by:
getCurrentNode
in interfaceDTMIterator
- Returns:
- The current node handle, or -1.
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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 and completely fill the cache.- Specified by:
runTo
in interfaceDTMIterator
- Parameters:
index
- The index to run to, or -1 if the iterator should be run to the end.
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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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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
This will traverse the hierarchy, 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:
visitor
- The visitor whose appropriate method will be called.
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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 if all the nodes in the iteration well be returned in document order.
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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
Get the number of nodes in the node list, which, in the XSLT 1 based counting system, is the last index position.- Specified by:
getLastPos
in interfaceSubContextList
- Specified by:
getLastPos
in classPredicatedNodeTest
- Parameters:
xctxt
- The XPath runtime context.- Returns:
- the number of nodes in the node list.
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