AI-generated Key Takeaways
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XPathVariableResolver
allows access and management of user-defined variables within XPath expressions. -
While variables can be changed between XPath expression evaluations, their values must remain constant during a single expression's evaluation.
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The
resolveVariable
method retrieves a variable's value by its QName, returning null if not found and throwing an exception if the QName is null.
XPathVariableResolver
provides access to the set of user defined XPath variables.
The XPathVariableResolver
and the XPath evaluator must adhere to a contract that
cannot be directly enforced by the API. Although variables may be mutable,
that is, an application may wish to evaluate the same XPath expression more
than once with different variable values, in the course of evaluating any
single XPath expression, a variable's value must be immutable.
Public Method Summary
abstract Object |
Public Methods
public abstract Object resolveVariable (QName variableName)
Find a variable in the set of available variables.
If variableName
is null
, then a NullPointerException
is thrown.
Parameters
variableName | The QName of the variable name. |
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Returns
- The variables value, or
null
if no variable namedvariableName
exists. The value returned must be of a type appropriate for the underlying object model.
Throws
NullPointerException | If variableName is null .
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