javax.xml.xpath.XPathExpression Maven / Gradle / Ivy
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* in compliance with the License.
*
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/*
* $Id: XPathExpression.java,v 1.5 2005/11/03 19:34:17 jeffsuttor Exp $
* %W% %E%
*
* Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
*/
package javax.xml.xpath;
import org.xml.sax.InputSource;
import javax.xml.namespace.QName;
/**
* XPathExpression provides access to compiled XPath 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 {@link XPathVariableResolver}.
* An {@link 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 {@link XPathFunctionResolver}.
* An {@link 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 {@link 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 {@link 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.
*
*
* @author Norman Walsh
* @author Jeff Suttor
* @version $Revision: 1.5 $, $Date: 2005/11/03 19:34:17 $
* @see XML Path Language (XPath) Version 1.0, Expressions
* @since 1.5
*/
public interface XPathExpression {
/**
*
Evaluate the compiled XPath expression in the specified context and return the result as the specified type.
*
* 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 {@link XPathConstants},
* then an IllegalArgumentException is thrown.
*
* If a null value is provided for
* item, an empty document will be used for the
* context.
* If returnType is null, then a NullPointerException is thrown.
*
* @param item The starting context (a node, for example).
* @param returnType The desired return type.
*
* @return The Object that is the result of evaluating the expression and converting the result to
* returnType.
*
* @throws XPathExpressionException If the expression cannot be evaluated.
* @throws IllegalArgumentException If returnType is not one of the types defined in {@link XPathConstants}.
* @throws NullPointerException If returnType is null.
*/
public Object evaluate(Object item, QName returnType)
throws XPathExpressionException;
/**
* Evaluate the compiled XPath expression in the specified context and return the result as a String.
*
* This method calls {@link #evaluate(Object item, QName returnType)} with a returnType of
* {@link XPathConstants#STRING}.
*
* See Evaluation of XPath Expressions for context item evaluation,
* variable, function and QName resolution and return type conversion.
*
* If a null value is provided for
* item, an empty document will be used for the
* context.
*
* @param item The starting context (a node, for example).
*
* @return The String that is the result of evaluating the expression and converting the result to a
* String.
*
* @throws XPathExpressionException If the expression cannot be evaluated.
*/
public String evaluate(Object item)
throws XPathExpressionException;
/**
*
Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as the
* specified type.
*
* This method builds a data model for the {@link InputSource} and calls
* {@link #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 {@link XPathConstants},
* then an IllegalArgumentException is thrown.
*
* If source or returnType is null,
* then a NullPointerException is thrown.
*
* @param source The InputSource of the document to evaluate over.
* @param returnType The desired return type.
*
* @return The Object that is the result of evaluating the expression and converting the result to
* returnType.
*
* @throws XPathExpressionException If the expression cannot be evaluated.
* @throws IllegalArgumentException If returnType is not one of the types defined in {@link XPathConstants}.
* @throws NullPointerException If source or returnType is null.
*/
public Object evaluate(InputSource source, QName returnType)
throws XPathExpressionException;
/**
* Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as a
* String.
*
* This method calls {@link #evaluate(InputSource source, QName returnType)} with a returnType of
* {@link 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.
*
* @param source The InputSource of the document to evaluate over.
*
* @return The String that is the result of evaluating the expression and converting the result to a
* String.
*
* @throws XPathExpressionException If the expression cannot be evaluated.
* @throws NullPointerException If source is null.
*/
public String evaluate(InputSource source)
throws XPathExpressionException;
}