net.sf.saxon.sxpath
Class XPathDynamicContext

java.lang.Object
  net.sf.saxon.sxpath.XPathDynamicContext

public class XPathDynamicContext
extends Object

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)

Constructor Summary

protected

XPathDynamicContext(ItemType contextItemType, XPathContextMajor contextObject, SlotManager stackFrameMap)

Method Summary

protected void	checkExternalVariables(SlotManager stackFrameMap, int numberOfExternals) Check that all external variables have been given a value
Item	getContextItem() Get the context item
ErrorListener	getErrorListener() Get the error listener.
URIResolver	getURIResolver() Get the URI resolver.
XPathContext	getXPathContextObject() For system use: get the wrapped XPathContext object
void	setContextItem(Item item) Set the context item for evaluation of the XPath Expression
void	setContextNode(Source source) Set the context item to a node derived from a supplied Source object.
void	setErrorListener(ErrorListener listener) Set the error listener.
void	setURIResolver(URIResolver resolver) Set an object that will be used to resolve URIs used in document(), etc.
void	setVariable(XPathVariable variable, ValueRepresentation value) Set the value of an external variable used within the XPath expression

Methods inherited from class java.lang.Object

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

Constructor Detail

XPathDynamicContext

protected XPathDynamicContext(ItemType contextItemType,
                              XPathContextMajor contextObject,
                              SlotManager stackFrameMap)

Method Detail

setContextNode

public void setContextNode(Source source)
                    throws XPathException

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 Saxon NodeInfo interface, representing a node in a tree, is one such implementation; others include StreamSource, SAXSource, and DOMSource

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

setContextItem

public void setContextItem(Item item)
                    throws XPathException

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

getContextItem

public Item getContextItem()

Get the context item

Returns:

the context item if there is one, or null otherwise

setVariable

public void setVariable(XPathVariable variable,
                        ValueRepresentation value)
                 throws XPathException

Set the value of an external variable used within the XPath expression

Parameters:

variable - the object representing the variable, as returned by the XPathEvaluator.declareVariable(String, String) method. Note that setting the value of a variable does not modify the XPathVariable 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)

setURIResolver

public void setURIResolver(URIResolver resolver)

Set an object that will be used to resolve URIs used in document(), etc.

Parameters:

resolver - An object that implements the URIResolver interface, or null.

Since:

9.2

getURIResolver

public URIResolver getURIResolver()

Get the URI resolver.

Returns:

the user-supplied URI resolver if there is one, or null otherwise.

Since:

9.2

setErrorListener

public void setErrorListener(ErrorListener listener)

Set the error listener.

Parameters:

listener - the ErrorListener to be used

Since:

9.2

getErrorListener

public ErrorListener getErrorListener()

Get the error listener.

Returns:

the ErrorListener in use

Since:

9.2

getXPathContextObject

public XPathContext getXPathContextObject()

For system use: get the wrapped XPathContext object

Returns:

the underlying XPathContext object

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 frame

numberOfExternals - the number of variables that need to be supplied

Throws:

XPathException - if required variables have not been given a value