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	/*
	* Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.xml.xpath;

	import javax.xml.namespace.QName;
	import org.xml.sax.InputSource;

	/**
	* {@code XPathExpression} provides access to compiled XPath expressions.
	* The XPath evaluation is affected by the factors described in the following table.
	*
	* <a id="XPathExpression-evaluation"></a>
	* <table class="striped">
	* <caption>Evaluation of XPath Expressions</caption>
	* <thead>
	* <tr>
	* <th scope="col">Factor</th>
	* <th scope="col">Behavior</th>
	* </tr>
	* </thead>
	* <tbody>
	* <tr>
	* <th scope="row">context</th>
	* <td>
	* 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.
	* </td>
	* </tr>
	* <tr>
	* <th scope="row">variables</th>
	* <td>
	* 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 {@code null} for the variable.
	* The value of a variable must be immutable through the course of any single evaluation.
	* </td>
	* </tr>
	* <tr>
	* <th scope="row">functions</th>
	* <td>
	* 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 {@code null} for the function.
	* </td>
	* </tr>
	* <tr>
	* <th scope="row">QNames</th>
	* <td>
	* QNames in the expression are resolved against the XPath namespace context.
	* </td>
	* </tr>
	* <tr>
	* <th scope="row">result</th>
	* <td>
	* 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.
	* </td>
	* </tr>
	* </tbody>
	* </table>
	*
	* <p>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 {@code evaluate}
	* method is invoked, applications may not recursively call
	* the {@code evaluate} method.
	*
	* @author Norman Walsh
	* @author Jeff Suttor
	* @see <a href="http://www.w3.org/TR/xpath#section-Expressions">XML Path Language (XPath) Version 1.0, Expressions</a>
	* @since 1.5
	*/
	public interface XPathExpression {


	/**
	* Evaluate the compiled XPath expression in the specified context and return the result as the specified type.
	*
	* <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
	* variable, function and QName resolution and return type conversion.
	*
	* <p>
	* The parameter {@code item} represents the context the XPath expression
	* will be operated on. The type of the context is implementation-dependent.
	* If the value is {@code null}, the operation must have no dependency on
	* the context, otherwise an XPathExpressionException will be thrown.
	*
	* @implNote
	* The type of the context is usually {@link org.w3c.dom.Node}.
	*
	* @param item The context the XPath expression will be evaluated in.
	* @param returnType The result type expected to be returned by the XPath expression.
	*
	* @return The {@code Object} that is the result of evaluating the expression and converting the result to
	* {@code returnType}.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If {@code returnType} is not one of the types defined in {@link XPathConstants}.
	* @throws NullPointerException If {@code returnType} is {@code 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 {@code String}.
	*
	* <p>This method calls {@link #evaluate(Object item, QName returnType)} with a {@code returnType} of
	* {@link XPathConstants#STRING}.
	*
	* <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
	* variable, function and QName resolution and return type conversion.
	*
	* <p>
	* The parameter {@code item} represents the context the XPath expression
	* will be operated on. The type of the context is implementation-dependent.
	* If the value is {@code null}, the operation must have no dependency on
	* the context, otherwise an XPathExpressionException will be thrown.
	*
	* @implNote
	* The type of the context is usually {@link org.w3c.dom.Node}.
	*
	* @param item The context the XPath expression will be evaluated in.
	*
	* @return The result of evaluating an XPath expression as a {@code 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 {@code InputSource} and return the result as the
	* specified type.
	*
	* <p>This method builds a data model for the {@link InputSource} and calls
	* {@link #evaluate(Object item, QName returnType)} on the resulting document object.
	*
	* <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
	* variable, function and QName resolution and return type conversion.
	*
	* <p>If {@code returnType} is not one of the types defined in {@link XPathConstants},
	* then an {@code IllegalArgumentException} is thrown.
	*
	* <p>If {@code source} or {@code returnType} is {@code null},
	* then a {@code NullPointerException} is thrown.
	*
	* @param source The {@code InputSource} of the document to evaluate over.
	* @param returnType The desired return type.
	*
	* @return The {@code Object} that is the result of evaluating the expression and converting the result to
	* {@code returnType}.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If {@code returnType} is not one of the types defined in {@link XPathConstants}.
	* @throws NullPointerException If {@code source or returnType} is {@code null}.
	*/
	public Object evaluate(InputSource source, QName returnType)
	throws XPathExpressionException;

	/**
	* Evaluate the compiled XPath expression in the context
	* of the specified {@code InputSource} and return the result as a
	* {@code String}.
	*
	* <p>This method calls {@link #evaluate(InputSource source, QName returnType)} with a {@code returnType} of
	* {@link XPathConstants#STRING}.
	*
	* <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
	* variable, function and QName resolution and return type conversion.
	*
	* <p>If {@code source} is {@code null}, then a {@code NullPointerException} is thrown.
	*
	* @param source The {@code InputSource} of the document to evaluate over.
	*
	* @return The {@code String} that is the result of evaluating the expression and converting the result to a
	* {@code String}.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws NullPointerException If {@code source} is {@code null}.
	*/
	public String evaluate(InputSource source)
	throws XPathExpressionException;

	/**
	* Evaluate the compiled XPath expression in the specified context, and return
	* the result with the type specified through the {@code class type}.
	*
	* <p>
	* The parameter {@code item} represents the context the XPath expression
	* will be operated on. The type of the context is implementation-dependent.
	* If the value is {@code null}, the operation must have no dependency on
	* the context, otherwise an XPathExpressionException will be thrown.
	*
	* @implNote
	* The type of the context is usually {@link org.w3c.dom.Node}.
	*
	* @implSpec
	* The default implementation in the XPath API is equivalent to:
	* <pre> {@code
	* (T)evaluate(item, XPathEvaluationResult.XPathResultType.getQNameType(type));
	* }</pre>
	*
	* Since the {@code evaluate} method does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type, specifying
	* XPathEvaluationResult as the type will result in IllegalArgumentException.
	* Any implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must override
	* this method.
	*
	* @param <T> The class type that will be returned by the XPath expression.
	* @param item The context the XPath expression will be evaluated in.
	* @param type The class type expected to be returned by the XPath expression,
	* must be one of the types described in section
	* <a href="package-summary.html#XPath.Datatypes.Class">3.2 Class types</a>
	* in the package summary.
	*
	* @return The result of evaluating the expression.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If {@code type} is not of the types
	* corresponding to the types defined in the {@link XPathEvaluationResult.XPathResultType
	* XPathResultType}, or XPathEvaluationResult is specified as the type but an
	* implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type is not available.
	* @throws NullPointerException If {@code type} is {@code null}.
	*
	* @since 9
	*/
	default <T>T evaluateExpression(Object item, Class<T> type)
	throws XPathExpressionException
	{
	return type.cast(evaluate(item, XPathEvaluationResult.XPathResultType.getQNameType(type)));
	}

	/**
	* Evaluate the compiled XPath expression in the specified context. This is
	* equivalent to calling {@link #evaluateExpression(Object item, Class type)}
	* with type {@link XPathEvaluationResult}:
	* <pre> {@code
	* evaluateExpression(item, XPathEvaluationResult.class);
	* }</pre>
	* <p>
	* The parameter {@code item} represents the context the XPath expression
	* will be operated on. The type of the context is implementation-dependent.
	* If the value is {@code null}, the operation must have no dependency on
	* the context, otherwise an XPathExpressionException will be thrown.
	*
	* @implNote
	* The type of the context is usually {@link org.w3c.dom.Node}.
	*
	* @implSpec
	* The default implementation in the XPath API is equivalent to:
	* <pre> {@code
	* evaluateExpression(item, XPathEvaluationResult.class);
	* }</pre>
	*
	* Since the {@code evaluate} method does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY}
	* type, the default implementation of this method will always throw an
	* IllegalArgumentException. Any implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must therefore
	* override this method.
	*
	* @param item The context the XPath expression will be evaluated in.
	*
	* @return The result of evaluating the expression.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If the implementation of this method
	* does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type.
	*
	* @since 9
	*/
	default XPathEvaluationResult<?> evaluateExpression(Object item)
	throws XPathExpressionException
	{
	return evaluateExpression(item, XPathEvaluationResult.class);
	}

	/**
	* Evaluate the compiled XPath expression in the specified context,
	* and return the result with the type specified through the {@code class type}
	* <p>
	* This method builds a data model for the {@link InputSource} and calls
	* {@link #evaluateExpression(Object item, Class type)} on the resulting
	* document object.
	* <P>
	* By default, the JDK's data model is {@link org.w3c.dom.Document}.
	*
	* @implSpec
	* The default implementation in the XPath API is equivalent to:
	* <pre> {@code
	(T)evaluate(source, XPathEvaluationResult.XPathResultType.getQNameType(type));
	* }</pre>
	*
	* Since the {@code evaluate} method does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type, specifying
	* XPathEvaluationResult as the type will result in IllegalArgumentException.
	* Any implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must override
	* this method.
	*
	* @param <T> The class type that will be returned by the XPath expression.
	* @param source The {@code InputSource} of the document to evaluate over.
	* @param type The class type expected to be returned by the XPath expression,
	* must be one of the types described in section
	* <a href="package-summary.html#XPath.Datatypes.Class">3.2 Class types</a>
	* in the package summary.
	*
	* @return The result of evaluating the expression.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If {@code type} is not of the types
	* corresponding to the types defined in the {@link XPathEvaluationResult.XPathResultType
	* XPathResultType}, or XPathEvaluationResult is specified as the type but an
	* implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type
	* is not available.
	* @throws NullPointerException If {@code source or type} is {@code null}.
	*
	* @since 9
	*/
	default <T>T evaluateExpression(InputSource source, Class<T> type)
	throws XPathExpressionException
	{
	return type.cast(evaluate(source, XPathEvaluationResult.XPathResultType.getQNameType(type)));
	}

	/**
	* Evaluate the compiled XPath expression in the specified context. This is
	* equivalent to calling {@link #evaluateExpression(InputSource source, Class type)}
	* with type {@link XPathEvaluationResult}:
	* <pre> {@code
	* evaluateExpression(source, XPathEvaluationResult.class);
	* }</pre>
	*
	* @implSpec
	* The default implementation in the XPath API is equivalent to:
	* <pre> {@code
	* (XPathEvaluationResult)evaluateExpression(source, XPathEvaluationResult.class);
	* }</pre>
	*
	* Since the {@code evaluate} method does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY}
	* type, the default implementation of this method will always throw an
	* IllegalArgumentException. Any implementation supporting the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must therefore
	* override this method.
	*
	* @param source The {@code InputSource} of the document to evaluate over.
	*
	* @return The result of evaluating the expression.
	*
	* @throws XPathExpressionException If the expression cannot be evaluated.
	* @throws IllegalArgumentException If the implementation of this method
	* does not support the
	* {@link XPathEvaluationResult.XPathResultType#ANY ANY} type.
	* @throws NullPointerException If {@code source} is {@code null}.
	*
	* @since 9
	*/
	default XPathEvaluationResult<?> evaluateExpression(InputSource source)
	throws XPathExpressionException
	{
	return evaluateExpression(source, XPathEvaluationResult.class);
	}
	}

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