#ifndef DOMXPathEvaluator_HEADER_GUARD_

#define DOMXPathEvaluator_HEADER_GUARD_

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 * 

 *      http://www.apache.org/licenses/LICENSE-2.0

 * 

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <xercesc/util/XercesDefs.hpp>

XERCES_CPP_NAMESPACE_BEGIN

class DOMXPathNSResolver;

class DOMXPathExpression;

class DOMNode;

/**

 * The evaluation of XPath expressions is provided by <code>DOMXPathEvaluator</code>. 

 * In a DOM implementation which supports the XPath 3.0 feature, the <code>DOMXPathEvaluator</code>

 * interface will be implemented on the same object which implements the Document interface permitting

 * it to be obtained by casting or by using the DOM Level 3 getInterface method. In this case the

 * implementation obtained from the Document supports the XPath DOM module and is compatible 

 * with the XPath 1.0 specification.

 * Evaluation of expressions with specialized extension functions or variables may not

 * work in all implementations and is, therefore, not portable. XPathEvaluator implementations

 * may be available from other sources that could provide specific support for specialized extension

 * functions or variables as would be defined by other specifications.

 * @since DOM Level 3

 */

class CDOM_EXPORT DOMXPathEvaluator

{

protected:

    // -----------------------------------------------------------------------

    //  Hidden constructors

    // -----------------------------------------------------------------------

    /** @name Hidden constructors */

    //@{    

    DOMXPathEvaluator() {};

    //@}

private:

    // -----------------------------------------------------------------------

    // Unimplemented constructors and operators

    // -----------------------------------------------------------------------

    /** @name Unimplemented constructors and operators */

    //@{

    DOMXPathEvaluator(const DOMXPathEvaluator &);

    DOMXPathEvaluator& operator = (const  DOMXPathEvaluator&);

    //@}

public:

    // -----------------------------------------------------------------------

    //  All constructors are hidden, just the destructor is available

    // -----------------------------------------------------------------------

    /** @name Destructor */

    //@{

    /**

     * Destructor

     *

     */

    virtual ~DOMXPathEvaluator() {};

    //@}

    // -----------------------------------------------------------------------

    // Virtual DOMDocument interface

    // -----------------------------------------------------------------------

    /** @name Functions introduced in DOM Level 3 */

    //@{

    /**

     * Creates a parsed XPath expression with resolved namespaces. This is useful

     * when an expression will be reused in an application since it makes it 

     * possible to compile the expression string into a more efficient internal 

     * form and preresolve all namespace prefixes which occur within the expression.

     * @param expression of type XMLCh - The XPath expression string to be parsed.

     * @param resolver of type <code>XPathNSResolver</code> - The resolver permits 

     * translation of all prefixes, including the xml namespace prefix, within the XPath expression

     * into appropriate namespace URIs. If this is specified as null, any namespace 

     * prefix within the expression will result in <code>DOMException</code> being thrown with the

     * code NAMESPACE_ERR.

     * @return <code>XPathExpression</code> The compiled form of the XPath expression.

     * @exception <code>XPathException</code>

     * INVALID_EXPRESSION_ERR: Raised if the expression is not legal according to the 

     * rules of the <code>DOMXPathEvaluator</code>.

     * @exception DOMException

     * NAMESPACE_ERR: Raised if the expression contains namespace prefixes which cannot

     * be resolved by the specified <code>XPathNSResolver</code>.

     * @since DOM Level 3

     */

    virtual const DOMXPathExpression*    createExpression(const XMLCh *expression, const DOMXPathNSResolver *resolver) = 0;

    /** Adapts any DOM node to resolve namespaces so that an XPath expression can be

     * easily evaluated relative to the context of the node where it appeared within

     * the document. This adapter works like the DOM Level 3 method lookupNamespaceURI

     * on nodes in resolving the namespaceURI from a given prefix using the current 

     * information available in the node's hierarchy at the time lookupNamespaceURI 

     * is called. also correctly resolving the implicit xml prefix.

     * @param nodeResolver of type <code>DOMNode</code> The node to be used as a context 

     * for namespace resolution.

     * @return <code>XPathNSResolver</code> <code>XPathNSResolver</code> which resolves namespaces 

     * with respect to the definitions in scope for a specified node.

     */

    virtual const DOMXPathNSResolver*    createNSResolver(DOMNode *nodeResolver) = 0;

    /**

     * Evaluates an XPath expression string and returns a result of the specified 

     * type if possible.

     * @param expression of type XMLCh The XPath expression string to be parsed 

     * and evaluated.

     * @param contextNode of type <code>DOMNode</code> The context is context node 

     * for the evaluation 

     * of this XPath expression. If the <code>DOMXPathEvaluator</code> was obtained by

     * casting the <code>DOMDocument</code> then this must be owned by the same 

     * document and must be a <code>DOMDocument</code>, <code>DOMElement</code>, 

     * <code>DOMAttribute</code>, <code>DOMText</code>, <code>DOMCDATASection</code>, 

     * <code>DOMComment</code>, <code>DOMProcessingInstruction</code>, or 

     * <code>XPathNamespace</code> node. If the context node is a <code>DOMText</code> or 

     * a <code>DOMCDATASection</code>, then the context is interpreted as the whole 

     * logical text node as seen by XPath, unless the node is empty in which case it

     * may not serve as the XPath context.

     * @param resolver of type <code>XPathNSResolver</code> The resolver permits 

     * translation of all prefixes, including the xml namespace prefix, within 

     * the XPath expression into appropriate namespace URIs. If this is specified 

     * as null, any namespace prefix within the expression will result in 

     * <code>DOMException</code> being thrown with the code NAMESPACE_ERR.

     * @param type of type unsigned short - If a specific type is specified, then 

     * the result will be returned as the corresponding type.

     * For XPath 1.0 results, this must be one of the codes of the <code>XPathResult</code>

     * interface.

     * @param result of type void* - The result specifies a specific result object

     * which may be reused and returned by this method. If this is specified as 

     * null or the implementation does not reuse the specified result, a new result

     * object will be constructed and returned.

     * For XPath 1.0 results, this object will be of type <code>XPathResult</code>.

     * @return void* The result of the evaluation of the XPath expression.

     * For XPath 1.0 results, this object will be of type <code>XPathResult</code>.

     * @exception <code>XPathException</code>

     * INVALID_EXPRESSION_ERR: Raised if the expression is not legal 

     * according to the rules of the <code>DOMXPathEvaluator</code>

     * TYPE_ERR: Raised if the result cannot be converted to return the specified type.

     * @exception DOMException

     * NAMESPACE_ERR: Raised if the expression contains namespace prefixes 

     * which cannot be resolved by the specified <code>XPathNSResolver</code>.

     * WRONG_DOCUMENT_ERR: The Node is from a document that is not supported 

     * by this <code>DOMXPathEvaluator</code>.

     * NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath context 

     * node or the request type is not permitted by this <code>DOMXPathEvaluator</code>.

     */

    virtual void* evaluate(const XMLCh *expression, DOMNode *contextNode, const DOMXPathNSResolver *resolver, 

                           unsigned short type, void* result) = 0;

    //@}

};

XERCES_CPP_NAMESPACE_END

#endif