Package net.sf.saxon.sxpath
Class XPathDynamicContext
java.lang.Object
net.sf.saxon.sxpath.XPathDynamicContext
This object represents the dynamic XPath execution context for use in the free-standing Saxon XPath API.
The dynamic context holds the context item and the values of external variables used by the XPath expression.
This object is always created via the method
XPathExpression.createDynamicContext(net.sf.saxon.om.Item)
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
XPathDynamicContext
(XPathContextMajor contextObject, SlotManager stackFrameMap) -
Method Summary
Modifier and TypeMethodDescriptionprotected void
checkExternalVariables
(SlotManager stackFrameMap, int numberOfExternals) Check that all external variables have been given a valueGet the context itemFor system use: get the wrapped XPathContext objectvoid
setContextItem
(Item item) Set the context item for evaluation of the XPath Expressionvoid
setContextNode
(Source source) Set the context item to a node derived from a supplied Source object.void
setVariable
(XPathVariable variable, ValueRepresentation value) Set the value of an external variable used within the XPath expression
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Constructor Details
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XPathDynamicContext
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Method Details
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setContextNode
Set the context item to a node derived from a supplied Source object. This may be any implementation of the Source interface recognized by Saxon. Note that the SaxonNodeInfo
interface, representing a node in a tree, is one such implementation; others includeStreamSource
,SAXSource
, andDOMSource
- Parameters:
source
- The source object representing the node that will be used as the context item- Throws:
XPathException
- if a failure occurs reading or parsing a Source object to build an input tree, or if the source is a document that was built under the wrong configuration
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setContextItem
Set the context item for evaluation of the XPath Expression- Parameters:
item
- the context item- Throws:
XPathException
- if the node is in a document that was built under the wrong configuration
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getContextItem
Get the context item- Returns:
- the context item if there is one, or null otherwise
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setVariable
Set the value of an external variable used within the XPath expression- Parameters:
variable
- the object representing the variable, as returned by theXPathEvaluator.declareVariable(String, String)
method. Note that setting the value of a variable does not modify theXPathVariable
object itself, which means that this method is thread-safe.value
- The value of the variable.- Throws:
XPathException
- if the supplied value does not conform to the required type of the variable; or if the supplied value contains a node that does not belong to this Configuration (or another Configuration that shares the same namePool)
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getXPathContextObject
For system use: get the wrapped XPathContext object- Returns:
- the underlying XPathContext object
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checkExternalVariables
protected void checkExternalVariables(SlotManager stackFrameMap, int numberOfExternals) throws XPathException Check that all external variables have been given a value- Parameters:
stackFrameMap
- describes the stack framenumberOfExternals
- the number of variables that need to be supplied- Throws:
XPathException
- if required variables have not been given a value
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