# XPathVariableResolver

public interface **XPathVariableResolver** <br />

`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.

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### Public Method Summary

|---|---|
| abstract [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) | [resolveVariable](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/xpath/XPathVariableResolver.html#resolveVariable(javax.xml.namespace.QName))([QName](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/namespace/QName.html) variableName) Find a variable in the set of available variables. |

## Public Methods

#### public abstract [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)
**resolveVariable**
([QName](https://developers.google.com/j2objc/javadoc/jre/reference/javax/xml/namespace/QName.html) variableName)

<br />

Find a variable in the set of available variables.

If `variableName` is `null`, then a `NullPointerException` is thrown.

<br />

##### Parameters

| variableName | The `QName` of the variable name. |
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##### Returns

- The variables value, or `null` if no variable named `variableName` exists. The value returned must be of a type appropriate for the underlying object model.

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | If `variableName` is `null`. |
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