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/*

 * Copyright (c) 2004 World Wide Web Consortium,

 *

 * (Massachusetts Institute of Technology, European Research Consortium for

 * Informatics and Mathematics, Keio University). All Rights Reserved. This

 * work is distributed under the W3C(r) Software License [1] 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.

 *

 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231

 */

package org.w3c.dom.xpath;

import org.w3c.dom.Node;

import org.w3c.dom.DOMException;

/**

 *  The evaluation of XPath expressions is provided by

 * <code>XPathEvaluator</code>. In a DOM implementation which supports the

 * XPath 3.0 feature, as described above, the <code>XPathEvaluator</code>

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

 * <code>Document</code> interface permitting it to be obtained by the usual

 * binding-specific method such as 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.

 * <p>Evaluation of expressions with specialized extension functions or

 * variables may not work in all implementations and is, therefore, not

 * portable. <code>XPathEvaluator</code> 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.

 * <p>See also the <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document Object Model (DOM) Level 3 XPath Specification</a>.

 */

public interface XPathEvaluator {

    /**

     * 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 The XPath expression string to be parsed.

     * @param resolver The <code>resolver</code> permits translation of all

     *   prefixes, including the <code>xml</code> namespace prefix, within

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

     *   specified as <code>null</code>, any namespace prefix within the

     *   expression will result in <code>DOMException</code> being thrown

     *   with the code <code>NAMESPACE_ERR</code>.

     * @return The compiled form of the XPath expression.

     * @exception XPathException

     *   INVALID_EXPRESSION_ERR: Raised if the expression is not legal

     *   according to the rules of the <code>XPathEvaluator</code>.

     * @exception DOMException

     *   NAMESPACE_ERR: Raised if the expression contains namespace prefixes

     *   which cannot be resolved by the specified

     *   <code>XPathNSResolver</code>.

     */

    public XPathExpression createExpression(String expression,

                                            XPathNSResolver resolver)

                                            throws XPathException, DOMException;

    /**

     * 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 <code>lookupNamespaceURI</code> 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 The node to be used as a context for namespace

     *   resolution.

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

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

     */

    public XPathNSResolver createNSResolver(Node nodeResolver);

    /**

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

     * specified type if possible.

     * @param expression The XPath expression string to be parsed and

     *   evaluated.

     * @param contextNode The <code>context</code> is context node for the

     *   evaluation of this XPath expression. If the XPathEvaluator was

     *   obtained by casting the <code>Document</code> then this must be

     *   owned by the same document and must be a <code>Document</code>,

     *   <code>Element</code>, <code>Attribute</code>, <code>Text</code>,

     *   <code>CDATASection</code>, <code>Comment</code>,

     *   <code>ProcessingInstruction</code>, or <code>XPathNamespace</code>

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

     *   <code>CDATASection</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 The <code>resolver</code> permits translation of all

     *   prefixes, including the <code>xml</code> namespace prefix, within

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

     *   specified as <code>null</code>, any namespace prefix within the

     *   expression will result in <code>DOMException</code> being thrown

     *   with the code <code>NAMESPACE_ERR</code>.

     * @param type If a specific <code>type</code> 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 The <code>result</code> specifies a specific result

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

     *   specified as <code>null</code>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 The result of the evaluation of the XPath expression.For XPath

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

     * @exception XPathException

     *   INVALID_EXPRESSION_ERR: Raised if the expression is not legal

     *   according to the rules of the <code>XPathEvaluator</code>i

     *   <br>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>.

     *   <br>WRONG_DOCUMENT_ERR: The Node is from a document that is not

     *   supported by this <code>XPathEvaluator</code>.

     *   <br>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>XPathEvaluator</code>.

     */

    public Object evaluate(String expression,

                           Node contextNode,

                           XPathNSResolver resolver,

                           short type,

                           Object result)

                           throws XPathException, DOMException;

}