org.apache.xpath
Class XPathContext

java.lang.Object
  |
  +--org.apache.xml.dtm.DTMManager
        |
        +--org.apache.xpath.XPathContext

public class XPathContext

extends DTMManager

**For advanced use only** Default class for the runtime execution context for XPath.

This class extends DTMManager but does not directly implement it.

Inner Class Summary

class

XPathContext.XPathExpressionContext

Field Summary

XMLReader	m_primaryReader The reader of the primary source tree.
static int	RECURSIONLIMIT The ammount to use for stacks that record information during the recursive execution.

Fields inherited from class org.apache.xml.dtm.DTMManager

IDENT_DTM_DEFAULT, IDENT_DTM_NODE_BITS, IDENT_MAX_DTMS, IDENT_NODE_DEFAULT, m_incremental

Constructor Summary

XPathContext()
Create an XPathContext instance.

XPathContext(java.lang.Object owner)
Create an XPathContext instance.

Method Summary

DTM	createDocumentFragment() Creates an empty DocumentFragment object.
DTMIterator	createDTMIterator(int node) Create a new DTMIterator that holds exactly one node.
DTMIterator	createDTMIterator(int whatToShow, DTMFilter filter, boolean entityReferenceExpansion) Create a new DTMIterator based only on a whatToShow and a DTMFilter.
DTMIterator	createDTMIterator(java.lang.Object xpathCompiler, int pos) Create a new DTMIterator based on an XPath UnionExpr.
DTMIterator	createDTMIterator(java.lang.String xpathString, PrefixResolver presolver) Create a new DTMIterator based on an XPath UnionExpr.
java.util.Stack	getAxesIteratorStackStacks()
int	getContextNode() Get the current context node.
DTMIterator	getContextNodeList() Get the current context node list.
java.util.Stack	getContextNodeListsStack()
DTMIterator	getContextNodes() Get the current context node list.
int	getCurrentExpressionNode() Get the current node that is the expression's context (i.e.
IntStack	getCurrentExpressionNodeStack()
int	getCurrentNode() Get the current context node.
LocPathIterator	getCurrentNodeList() **For internal use only** Get the current node list as defined by the XSLT spec.
IntStack	getCurrentNodeStack()
DTM	getDTM(int nodeHandle) Get an instance of a DTM that "owns" a node handle.
DTM	getDTM(Source source, boolean unique, DTMWSFilter wsfilter, boolean incremental, boolean doIndexing) Get an instance of a DTM, loaded with the content from the specified source.
int	getDTMHandleFromNode(Node node) Given a W3C DOM node, try and return a DTM handle.
int	getDTMIdentity(DTM dtm) %TBD% Doc
DTMManager	getDTMManager() Return the DTMManager object.
ErrorListener	getErrorListener() Get the ErrorListener where errors and warnings are to be reported.
ExpressionContext	getExpressionContext() The the expression context for extensions for this context.
DTM	getGlobalRTFDTM() Get a DTM to be used as a container for a global Result Tree Fragment.
int	getIteratorRoot() Get the current location path iterator root.
PrefixResolver	getNamespaceContext() Get the current namespace context for the xpath.
java.lang.Object	getOwnerObject() Get the "owner" context of this context, which should be, in the case of XSLT, the Transformer object.
int	getPredicatePos()
int	getPredicateRoot() Get the current predicate root.
XMLReader	getPrimaryReader() Get primary XMLReader associated with this execution context.
DTM	getRTFDTM() Get a DTM to be used as a container for a dynamic Result Tree Fragment.
SourceLocator	getSAXLocator() Get the current locater in the stylesheet.
SourceTreeManager	getSourceTreeManager() Get the SourceTreeManager associated with this execution context.
SubContextList	getSubContextList() **For internal use only** Get the current axes iterator, or return null if none.
URIResolver	getURIResolver() Get the URIResolver associated with this execution context.
VariableStack	getVarStack() Get the variable stack, which is in charge of variables and parameters.
void	popContextNodeList() **For internal use only** Pop the current context node list.
void	popCurrentExpressionNode() Pop the current node that is the expression's context (i.e.
void	popCurrentNode() Pop the current context node.
void	popCurrentNodeAndExpression() Set the current context node.
void	popExpressionState() Pop the current context node, expression node, and prefix resolver.
void	popIteratorRoot() Pop the current location path iterator root.
void	popNamespaceContext() Pop the current namespace context for the xpath.
void	popPredicatePos()
void	popPredicateRoot() Pop the current predicate root.
void	popRTFContext() Pop the RTFDTM's context mark.
void	popSAXLocator() Pop the current locater.
void	popSubContextList() **For internal use only** Pop the last pushed axes iterator.
void	pushContextNodeList(DTMIterator nl) **For internal use only** Set the current context node list.
void	pushCurrentExpressionNode(int n) Set the current node that is the expression's context (i.e.
void	pushCurrentNode(int n) Set the current context node.
void	pushCurrentNodeAndExpression(int cn, int en) Set the current context node and expression node.
void	pushExpressionState(int cn, int en, PrefixResolver nc) Push the current context node, expression node, and prefix resolver.
void	pushIteratorRoot(int n) Set the current location path iterator root.
void	pushNamespaceContext(PrefixResolver pr) Push a current namespace context for the xpath.
void	pushNamespaceContextNull() Just increment the namespace contest stack, so that setNamespaceContext can be used on the slot.
void	pushPredicatePos(int n)
void	pushPredicateRoot(int n) Set the current predicate root.
void	pushRTFContext() Push the RTFDTM's context mark, to allows discarding RTFs added after this point.
void	pushSAXLocator(SourceLocator location) Set the current locater in the stylesheet.
void	pushSAXLocatorNull() Push a slot on the locations stack so that setSAXLocator can be repeatedly called.
void	pushSubContextList(SubContextList iter) **For internal use only** Push a TreeWalker on the stack.
boolean	release(DTM dtm, boolean shouldHardDelete) Release a DTM either to a lru pool, or completely remove reference.
void	reset() Reset for new run.
void	setAxesIteratorStackStacks(java.util.Stack s)
void	setContextNodeListsStack(java.util.Stack s)
void	setCurrentExpressionNodeStack(IntStack nv)
void	setCurrentNodeStack(IntStack nv)
void	setErrorListener(ErrorListener listener) Set the ErrorListener where errors and warnings are to be reported.
void	setNamespaceContext(PrefixResolver pr) Get the current namespace context for the xpath.
void	setPrimaryReader(XMLReader reader) Set primary XMLReader associated with this execution context.
void	setSAXLocator(SourceLocator location) Set the current locater in the stylesheet.
void	setSourceTreeManager(SourceTreeManager mgr) Set the SourceTreeManager associated with this execution context.
void	setURIResolver(URIResolver resolver) Set the URIResolver associated with this execution context.
void	setVarStack(VariableStack varStack) Get the variable stack, which is in charge of variables and parameters.

Methods inherited from class org.apache.xml.dtm.DTMManager

getDTMIdentityMask, getIncremental, getNodeIdentityMask, getXMLStringFactory, newInstance, setIncremental, setXMLStringFactory

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_primaryReader

public XMLReader m_primaryReader

The reader of the primary source tree.

RECURSIONLIMIT

public static final int RECURSIONLIMIT

The ammount to use for stacks that record information during the recursive execution.

Constructor Detail

XPathContext

public XPathContext()

Create an XPathContext instance.

XPathContext

public XPathContext(java.lang.Object owner)

Create an XPathContext instance.

Parameters:

owner - Value that can be retrieved via the getOwnerObject() method.

See Also:

getOwnerObject()

Method Detail

getDTMManager

public DTMManager getDTMManager()

Return the DTMManager object. Though XPathContext context extends the DTMManager, it really is a proxy for the real DTMManager. If a caller needs to make a lot of calls to the DTMManager, it is faster if it gets the real one from this function.

getDTM

public DTM getDTM(Source source,
                  boolean unique,
                  DTMWSFilter wsfilter,
                  boolean incremental,
                  boolean doIndexing)

Get an instance of a DTM, loaded with the content from the specified source. If the unique flag is true, a new instance will always be returned. Otherwise it is up to the DTMManager to return a new instance or an instance that it already created and may be being used by someone else. (I think more parameters will need to be added for error handling, and entity resolution).

Parameters:

source - the specification of the source object, which may be null, in which case it is assumed that node construction will take by some other means.

unique - true if the returned DTM must be unique, probably because it is going to be mutated.

whiteSpaceFilter - Enables filtering of whitespace nodes, and may be null.

incremental - true if the construction should try and be incremental.

doIndexing - true if the caller considers it worth it to use indexing schemes.

Returns:

a non-null DTM reference.

Overrides:

getDTM in class DTMManager

getDTM

public DTM getDTM(int nodeHandle)

Get an instance of a DTM that "owns" a node handle.

Parameters:

nodeHandle - the nodeHandle.

Returns:

a non-null DTM reference.

Overrides:

getDTM in class DTMManager

getDTMHandleFromNode

public int getDTMHandleFromNode(Node node)

Given a W3C DOM node, try and return a DTM handle. Note: calling this may be non-optimal.

Parameters:

node - Non-null reference to a DOM node.

Returns:

a valid DTM handle.

Overrides:

getDTMHandleFromNode in class DTMManager

getDTMIdentity

public int getDTMIdentity(DTM dtm)

%TBD% Doc

Overrides:

getDTMIdentity in class DTMManager

createDocumentFragment

public DTM createDocumentFragment()

Creates an empty DocumentFragment object.

Returns:

A new DocumentFragment handle.

Overrides:

createDocumentFragment in class DTMManager

release

public boolean release(DTM dtm,
                       boolean shouldHardDelete)

Release a DTM either to a lru pool, or completely remove reference. DTMs without system IDs are always hard deleted. State: experimental.

Parameters:

dtm - The DTM to be released.

shouldHardDelete - True if the DTM should be removed no matter what.

Returns:

true if the DTM was removed, false if it was put back in a lru pool.

Overrides:

release in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(java.lang.Object xpathCompiler,
                                     int pos)

Create a new DTMIterator based on an XPath UnionExpr.

Parameters:

xpathCompiler - ??? Somehow we need to pass in a subpart of the expression. I hate to do this with strings, since the larger expression has already been parsed.

pos - The position in the expression.

Returns:

The newly created DTMIterator.

Overrides:

createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(java.lang.String xpathString,
                                     PrefixResolver presolver)

Create a new DTMIterator based on an XPath UnionExpr.

Parameters:

xpathString - Must be a valid string expressing a UnionExpr.

presolver - An object that can resolve prefixes to namespace URLs.

Returns:

The newly created DTMIterator.

Overrides:

createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(int whatToShow,
                                     DTMFilter filter,
                                     boolean entityReferenceExpansion)

Create a new DTMIterator based only on a whatToShow and a DTMFilter. The traversal semantics are defined as the descendant access.

Parameters:

whatToShow - This flag specifies which node types may appear in the logical view of the tree presented by the iterator. See the description of NodeFilter for the set of possible SHOW_ values.These flags can be combined using OR.

filter - The NodeFilter to be used with this TreeWalker, or null to indicate no filter.

entityReferenceExpansion - The value of this flag determines whether entity reference nodes are expanded.

Returns:

The newly created NodeIterator.

Overrides:

createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(int node)

Create a new DTMIterator that holds exactly one node.

Parameters:

node - The node handle that the DTMIterator will iterate to.

Returns:

The newly created DTMIterator.

Overrides:

createDTMIterator in class DTMManager

reset

public void reset()

Reset for new run.

setSAXLocator

public void setSAXLocator(SourceLocator location)

Set the current locater in the stylesheet.

Parameters:

location - The location within the stylesheet.

pushSAXLocator

public void pushSAXLocator(SourceLocator location)

Set the current locater in the stylesheet.

Parameters:

location - The location within the stylesheet.

pushSAXLocatorNull

public void pushSAXLocatorNull()

Push a slot on the locations stack so that setSAXLocator can be repeatedly called.

Parameters:

location - The location within the stylesheet.

popSAXLocator

public void popSAXLocator()

Pop the current locater.

getSAXLocator

public SourceLocator getSAXLocator()

Get the current locater in the stylesheet.

Returns:

The location within the stylesheet, or null if not known.

getOwnerObject

public java.lang.Object getOwnerObject()

Get the "owner" context of this context, which should be, in the case of XSLT, the Transformer object. This is needed so that XSLT functions can get the Transformer.

Returns:

The owner object passed into the constructor, or null.

getVarStack

public final VariableStack getVarStack()

Get the variable stack, which is in charge of variables and parameters.

Returns:

the variable stack, which should not be null.

setVarStack

public final void setVarStack(VariableStack varStack)

Get the variable stack, which is in charge of variables and parameters.

Parameters:

varStack - non-null reference to the variable stack.

getSourceTreeManager

public final SourceTreeManager getSourceTreeManager()

Get the SourceTreeManager associated with this execution context.

Returns:

the SourceTreeManager associated with this execution context.

setSourceTreeManager

public void setSourceTreeManager(SourceTreeManager mgr)

Set the SourceTreeManager associated with this execution context.

Parameters:

mgr - the SourceTreeManager to be associated with this execution context.

getErrorListener

public final ErrorListener getErrorListener()

Get the ErrorListener where errors and warnings are to be reported.

Returns:

A non-null ErrorListener reference.

setErrorListener

public void setErrorListener(ErrorListener listener)
                      throws java.lang.IllegalArgumentException

Set the ErrorListener where errors and warnings are to be reported.

Parameters:

listener - A non-null ErrorListener reference.

getURIResolver

public final URIResolver getURIResolver()

Get the URIResolver associated with this execution context.

Returns:

a URI resolver, which may be null.

setURIResolver

public void setURIResolver(URIResolver resolver)

Set the URIResolver associated with this execution context.

Parameters:

resolver - the URIResolver to be associated with this execution context, may be null to clear an already set resolver.

getPrimaryReader

public final XMLReader getPrimaryReader()

Get primary XMLReader associated with this execution context.

Returns:

The reader of the primary source tree.

setPrimaryReader

public void setPrimaryReader(XMLReader reader)

Set primary XMLReader associated with this execution context.

Parameters:

reader - The reader of the primary source tree.

getContextNodeListsStack

public java.util.Stack getContextNodeListsStack()

setContextNodeListsStack

public void setContextNodeListsStack(java.util.Stack s)

getContextNodeList

public final DTMIterator getContextNodeList()

Get the current context node list.

Returns:

the current node list, also refered to here as a context node list.

pushContextNodeList

public final void pushContextNodeList(DTMIterator nl)

**For internal use only** Set the current context node list.

Parameters:

nl - the current node list, also refered to here as a context node list.

popContextNodeList

public final void popContextNodeList()

**For internal use only** Pop the current context node list.

getCurrentNodeStack

public IntStack getCurrentNodeStack()

setCurrentNodeStack

public void setCurrentNodeStack(IntStack nv)

getCurrentNode

public final int getCurrentNode()

Get the current context node.

Returns:

the current node.

pushCurrentNodeAndExpression

public final void pushCurrentNodeAndExpression(int cn,
                                               int en)

Set the current context node and expression node.

Parameters:

cn - the current node.

en - the sub-expression context node.

popCurrentNodeAndExpression

public final void popCurrentNodeAndExpression()

Set the current context node.

pushExpressionState

public final void pushExpressionState(int cn,
                                      int en,
                                      PrefixResolver nc)

Push the current context node, expression node, and prefix resolver.

Parameters:

cn - the current node.

en - the sub-expression context node.

nc - the namespace context (prefix resolver.

popExpressionState

public final void popExpressionState()

Pop the current context node, expression node, and prefix resolver.

pushCurrentNode

public final void pushCurrentNode(int n)

Set the current context node.

Parameters:

n - the current node.

popCurrentNode

public final void popCurrentNode()

Pop the current context node.

pushPredicateRoot

public final void pushPredicateRoot(int n)

Set the current predicate root.

popPredicateRoot

public final void popPredicateRoot()

Pop the current predicate root.

getPredicateRoot

public final int getPredicateRoot()

Get the current predicate root.

pushIteratorRoot

public final void pushIteratorRoot(int n)

Set the current location path iterator root.

popIteratorRoot

public final void popIteratorRoot()

Pop the current location path iterator root.

getIteratorRoot

public final int getIteratorRoot()

Get the current location path iterator root.

getCurrentExpressionNodeStack

public IntStack getCurrentExpressionNodeStack()

setCurrentExpressionNodeStack

public void setCurrentExpressionNodeStack(IntStack nv)

getPredicatePos

public final int getPredicatePos()

pushPredicatePos

public final void pushPredicatePos(int n)

popPredicatePos

public final void popPredicatePos()

getCurrentExpressionNode

public final int getCurrentExpressionNode()

Get the current node that is the expression's context (i.e. for current() support).

Returns:

The current sub-expression node.

pushCurrentExpressionNode

public final void pushCurrentExpressionNode(int n)

Set the current node that is the expression's context (i.e. for current() support).

Parameters:

n - The sub-expression node to be current.

popCurrentExpressionNode

public final void popCurrentExpressionNode()

Pop the current node that is the expression's context (i.e. for current() support).

getNamespaceContext

public final PrefixResolver getNamespaceContext()

Get the current namespace context for the xpath.

Returns:

the current prefix resolver for resolving prefixes to namespace URLs.

setNamespaceContext

public final void setNamespaceContext(PrefixResolver pr)

Get the current namespace context for the xpath.

Parameters:

pr - the prefix resolver to be used for resolving prefixes to namespace URLs.

pushNamespaceContext

public final void pushNamespaceContext(PrefixResolver pr)

Push a current namespace context for the xpath.

Parameters:

pr - the prefix resolver to be used for resolving prefixes to namespace URLs.

pushNamespaceContextNull

public final void pushNamespaceContextNull()

Just increment the namespace contest stack, so that setNamespaceContext can be used on the slot.

popNamespaceContext

public final void popNamespaceContext()

Pop the current namespace context for the xpath.

getAxesIteratorStackStacks

public java.util.Stack getAxesIteratorStackStacks()

setAxesIteratorStackStacks

public void setAxesIteratorStackStacks(java.util.Stack s)

pushSubContextList

public final void pushSubContextList(SubContextList iter)

**For internal use only** Push a TreeWalker on the stack.

Parameters:

iter - A sub-context AxesWalker.

popSubContextList

public final void popSubContextList()

**For internal use only** Pop the last pushed axes iterator.

getSubContextList

public SubContextList getSubContextList()

**For internal use only** Get the current axes iterator, or return null if none.

Returns:

the sub-context node list.

getCurrentNodeList

public LocPathIterator getCurrentNodeList()

**For internal use only** Get the current node list as defined by the XSLT spec.

Returns:

the current node list.

getContextNode

public final int getContextNode()

Get the current context node.

Returns:

The current context node.

getContextNodes

public final DTMIterator getContextNodes()

Get the current context node list.

Returns:

An iterator for the current context list, as defined in XSLT.

getExpressionContext

public ExpressionContext getExpressionContext()

The the expression context for extensions for this context.

Returns:

An object that implements the ExpressionContext.

getGlobalRTFDTM

public DTM getGlobalRTFDTM()

Get a DTM to be used as a container for a global Result Tree Fragment. This will always be an instance of (derived from? equivalent to?) SAX2DTM, since each RTF is constructed by temporarily redirecting our SAX output to it. It may be a single DTM containing for multiple fragments, if the implementation supports that. Note: The distinction between this method and getRTFDTM() is that the latter allocates space from the dynamic variable stack (m_rtfdtm_stack), which may be pruned away again as the templates which defined those variables are exited. Global variables may be bound late (see XUnresolvedVariable), and never want to be discarded, hence we need to allocate them separately and don't actually need a stack to track them.

Returns:

a non-null DTM reference.

getRTFDTM

public DTM getRTFDTM()

Get a DTM to be used as a container for a dynamic Result Tree Fragment. This will always be an instance of (derived from? equivalent to?) SAX2DTM, since each RTF is constructed by temporarily redirecting our SAX output to it. It may be a single DTM containing for multiple fragments, if the implementation supports that.

Returns:

a non-null DTM reference.

pushRTFContext

public void pushRTFContext()

Push the RTFDTM's context mark, to allows discarding RTFs added after this point. (If it doesn't exist we don't push, since we might still be able to get away with not creating it. That requires that excessive pops be harmless.)

popRTFContext

public void popRTFContext()

Pop the RTFDTM's context mark. This discards any RTFs added after the last mark was set. If there is no RTF DTM, there's nothing to pop so this becomes a no-op. If pushes were issued before this was called, we count on the fact that popRewindMark is defined such that overpopping just resets to empty. Complicating factor: We need to handle the case of popping back to a previous RTF DTM, if one of the weird produce-an-RTF-to-build-an-RTF cases arose. Basically: If pop says this DTM is now empty, then return to the previous if one exists, in whatever state we left it in. UGLY, but hopefully the situation which forces us to consider this will arise exceedingly rarely.