XPath

public interface XPath

XPath provides access to the XPath evaluation environment and expressions.

Evaluation of XPath Expressions.
context If a request is made to evaluate the expression in the absence of a context item, an empty document node will be used for the context. For the purposes of evaluating XPath expressions, a DocumentFragment is treated like a Document node.
variables If the expression contains a variable reference, its value will be found through the XPathVariableResolver set with setXPathVariableResolver(XPathVariableResolver). An XPathExpressionException is raised if the variable resolver is undefined or the resolver returns null for the variable. The value of a variable must be immutable through the course of any single evaluation.

functions If the expression contains a function reference, the function will be found through the XPathFunctionResolver set with setXPathFunctionResolver(XPathFunctionResolver). An XPathExpressionException is raised if the function resolver is undefined or the function resolver returns null for the function.

QNames QNames in the expression are resolved against the XPath namespace context set with setNamespaceContext(NamespaceContext).
result This result of evaluating an expression is converted to an instance of the desired return type. Valid return types are defined in XPathConstants. Conversion to the return type follows XPath conversion rules.

Public Method Summary

abstract XPathExpression
compile(String expression)

Compile an XPath expression for later evaluation.

abstract Object
evaluate(String expression, Object item, QName returnType)

Evaluate an XPath expression in the specified context and return the result as the specified type.

abstract String
evaluate(String expression, Object item)

Evaluate an XPath expression in the specified context and return the result as a String.

abstract Object
evaluate(String expression, InputSource source, QName returnType)

Evaluate an XPath expression in the context of the specified InputSource and return the result as the specified type.