public interface XPathExpression
XPathExpression provides access to compiled XPath expressions. The XPath evaluation is affected by the factors described in the following table. | Factor | Behavior |
|---|---|
| context | The type of the context is implementation-dependent. If the value is null, the operation must have no dependency on the context, otherwise an XPathExpressionException will be thrown. 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. 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. 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. |
| 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. |
An XPath expression is not thread-safe and not reentrant. In other words, it is the application's responsibility to make sure that one XPathExpression object is not used from more than one thread at any given time, and while the evaluate method is invoked, applications may not recursively call the evaluate method.
| Modifier and Type | Method | Description |
|---|---|---|
String |
evaluate |
Evaluate the compiled XPath expression in the specified context and return the result as a String. |
Object |
evaluate |
Evaluate the compiled XPath expression in the specified context and return the result as the specified type. |
String |
evaluate |
Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as a String. |
Object |
evaluate |
Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as the specified type. |
default XPathEvaluationResult |
evaluateExpression |
Evaluate the compiled XPath expression in the specified context. |
default <T> T |
evaluateExpression |
Evaluate the compiled XPath expression in the specified context, and return the result with the type specified through the class type. |
default XPathEvaluationResult |
evaluateExpression |
Evaluate the compiled XPath expression in the specified context. |
default <T> T |
evaluateExpression |
Evaluate the compiled XPath expression in the specified context, and return the result with the type specified through the class type
|
Object evaluate(Object item, QName returnType) throws XPathExpressionException
See Evaluation of XPath Expressions for context item evaluation, variable, function and QName resolution and return type conversion.
The parameter item represents the context the XPath expression will be operated on. The type of the context is implementation-dependent. If the value is null, the operation must have no dependency on the context, otherwise an XPathExpressionException will be thrown.
Node.item - The context the XPath expression will be evaluated in.returnType - The result type expected to be returned by the XPath expression.Object that is the result of evaluating the expression and converting the result to returnType.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If returnType is not one of the types defined in XPathConstants.NullPointerException - If returnType is null.String evaluate(Object item) throws XPathExpressionException
String. This method calls evaluate(Object item, QName returnType) with a returnType of XPathConstants.STRING.
See Evaluation of XPath Expressions for context item evaluation, variable, function and QName resolution and return type conversion.
The parameter item represents the context the XPath expression will be operated on. The type of the context is implementation-dependent. If the value is null, the operation must have no dependency on the context, otherwise an XPathExpressionException will be thrown.
Node.item - The context the XPath expression will be evaluated in.String.XPathExpressionException - If the expression cannot be evaluated.Object evaluate(InputSource source, QName returnType) throws XPathExpressionException
InputSource and return the result as the specified type. This method builds a data model for the InputSource and calls evaluate(Object item, QName returnType) on the resulting document object.
See Evaluation of XPath Expressions for context item evaluation, variable, function and QName resolution and return type conversion.
If returnType is not one of the types defined in XPathConstants, then an IllegalArgumentException is thrown.
If source or returnType is null, then a NullPointerException is thrown.
source - The InputSource of the document to evaluate over.returnType - The desired return type.Object that is the result of evaluating the expression and converting the result to returnType.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If returnType is not one of the types defined in XPathConstants.NullPointerException - If source or returnType is null.String evaluate(InputSource source) throws XPathExpressionException
InputSource and return the result as a String. This method calls evaluate(InputSource source, QName returnType) with a returnType of XPathConstants.STRING.
See Evaluation of XPath Expressions for context item evaluation, variable, function and QName resolution and return type conversion.
If source is null, then a NullPointerException is thrown.
source - The InputSource of the document to evaluate over.String that is the result of evaluating the expression and converting the result to a String.XPathExpressionException - If the expression cannot be evaluated.NullPointerException - If source is null.default <T> T evaluateExpression(Object item, Class<T> type) throws XPathExpressionException
class type. The parameter item represents the context the XPath expression will be operated on. The type of the context is implementation-dependent. If the value is null, the operation must have no dependency on the context, otherwise an XPathExpressionException will be thrown.
(T)evaluate(item, XPathEvaluationResult.XPathResultType.getQNameType(type));
Since the evaluate method does not support the ANY type, specifying XPathEvaluationResult as the type will result in IllegalArgumentException. Any implementation supporting the ANY type must override this method.Node.T - The class type that will be returned by the XPath expression.item - The context the XPath expression will be evaluated in.type - The class type expected to be returned by the XPath expression, must be one of the types described in section 3.2 Class types in the package summary.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If type is not of the types corresponding to the types defined in the XPathResultType, or XPathEvaluationResult is specified as the type but an implementation supporting the ANY type is not available.NullPointerException - If type is null.default XPathEvaluationResult<?> evaluateExpression(Object item) throws XPathExpressionException
evaluateExpression(Object item, Class type) with type XPathEvaluationResult:
evaluateExpression(item, XPathEvaluationResult.class);
The parameter item represents the context the XPath expression will be operated on. The type of the context is implementation-dependent. If the value is null, the operation must have no dependency on the context, otherwise an XPathExpressionException will be thrown.
evaluateExpression(item, XPathEvaluationResult.class);
Since the evaluate method does not support the ANY type, the default implementation of this method will always throw an IllegalArgumentException. Any implementation supporting the ANY type must therefore override this method.Node.item - The context the XPath expression will be evaluated in.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If the implementation of this method does not support the ANY type.default <T> T evaluateExpression(InputSource source, Class<T> type) throws XPathExpressionException
class type This method builds a data model for the InputSource and calls evaluateExpression(Object item, Class type) on the resulting document object.
By default, the JDK's data model is Document.
(T)evaluate(source, XPathEvaluationResult.XPathResultType.getQNameType(type));
Since the evaluate method does not support the ANY type, specifying XPathEvaluationResult as the type will result in IllegalArgumentException. Any implementation supporting the ANY type must override this method.T - The class type that will be returned by the XPath expression.source - The InputSource of the document to evaluate over.type - The class type expected to be returned by the XPath expression, must be one of the types described in section 3.2 Class types in the package summary.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If type is not of the types corresponding to the types defined in the XPathResultType, or XPathEvaluationResult is specified as the type but an implementation supporting the ANY type is not available.NullPointerException - If source or type is null.default XPathEvaluationResult<?> evaluateExpression(InputSource source) throws XPathExpressionException
evaluateExpression(InputSource source, Class type) with type XPathEvaluationResult:
evaluateExpression(source, XPathEvaluationResult.class);
(XPathEvaluationResult)evaluateExpression(source, XPathEvaluationResult.class);
Since the evaluate method does not support the ANY type, the default implementation of this method will always throw an IllegalArgumentException. Any implementation supporting the ANY type must therefore override this method.source - The InputSource of the document to evaluate over.XPathExpressionException - If the expression cannot be evaluated.IllegalArgumentException - If the implementation of this method does not support the ANY type.NullPointerException - If source is null.
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.xml/javax/xml/xpath/XPathExpression.html