Source for org.w3c.dom.xpath.XPathEvaluator

   1: /*
   2:  * Copyright (c) 2004 World Wide Web Consortium,
   3:  *
   4:  * (Massachusetts Institute of Technology, European Research Consortium for
   5:  * Informatics and Mathematics, Keio University). All Rights Reserved. This
   6:  * work is distributed under the W3C(r) Software License [1] in the hope that
   7:  * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
   8:  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   9:  *
  10:  * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
  11:  */
  12: 
  13: package org.w3c.dom.xpath;
  14: 
  15: import org.w3c.dom.Node;
  16: import org.w3c.dom.DOMException;
  17: 
  18: /**
  19:  *  The evaluation of XPath expressions is provided by 
  20:  * <code>XPathEvaluator</code>. In a DOM implementation which supports the 
  21:  * XPath 3.0 feature, as described above, the <code>XPathEvaluator</code> 
  22:  * interface will be implemented on the same object which implements the 
  23:  * <code>Document</code> interface permitting it to be obtained by the usual 
  24:  * binding-specific method such as casting or by using the DOM Level 3 
  25:  * getInterface method. In this case the implementation obtained from the 
  26:  * Document supports the XPath DOM module and is compatible with the XPath 
  27:  * 1.0 specification. 
  28:  * <p>Evaluation of expressions with specialized extension functions or 
  29:  * variables may not work in all implementations and is, therefore, not 
  30:  * portable. <code>XPathEvaluator</code> implementations may be available 
  31:  * from other sources that could provide specific support for specialized 
  32:  * extension functions or variables as would be defined by other 
  33:  * specifications. 
  34:  * <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>.
  35:  */
  36: public interface XPathEvaluator {
  37:     /**
  38:      * Creates a parsed XPath expression with resolved namespaces. This is 
  39:      * useful when an expression will be reused in an application since it 
  40:      * makes it possible to compile the expression string into a more 
  41:      * efficient internal form and preresolve all namespace prefixes which 
  42:      * occur within the expression.
  43:      * @param expression The XPath expression string to be parsed.
  44:      * @param resolver The <code>resolver</code> permits translation of all 
  45:      *   prefixes, including the <code>xml</code> namespace prefix, within 
  46:      *   the XPath expression into appropriate namespace URIs. If this is 
  47:      *   specified as <code>null</code>, any namespace prefix within the 
  48:      *   expression will result in <code>DOMException</code> being thrown 
  49:      *   with the code <code>NAMESPACE_ERR</code>.
  50:      * @return The compiled form of the XPath expression.
  51:      * @exception XPathException
  52:      *   INVALID_EXPRESSION_ERR: Raised if the expression is not legal 
  53:      *   according to the rules of the <code>XPathEvaluator</code>.
  54:      * @exception DOMException
  55:      *   NAMESPACE_ERR: Raised if the expression contains namespace prefixes 
  56:      *   which cannot be resolved by the specified 
  57:      *   <code>XPathNSResolver</code>.
  58:      */
  59:     public XPathExpression createExpression(String expression, 
  60:                                             XPathNSResolver resolver)
  61:                                             throws XPathException, DOMException;
  62: 
  63:     /**
  64:      * Adapts any DOM node to resolve namespaces so that an XPath expression 
  65:      * can be easily evaluated relative to the context of the node where it 
  66:      * appeared within the document. This adapter works like the DOM Level 3 
  67:      * method <code>lookupNamespaceURI</code> on nodes in resolving the 
  68:      * namespaceURI from a given prefix using the current information 
  69:      * available in the node's hierarchy at the time lookupNamespaceURI is 
  70:      * called. also correctly resolving the implicit xml prefix.
  71:      * @param nodeResolver The node to be used as a context for namespace 
  72:      *   resolution.
  73:      * @return <code>XPathNSResolver</code> which resolves namespaces with 
  74:      *   respect to the definitions in scope for a specified node.
  75:      */
  76:     public XPathNSResolver createNSResolver(Node nodeResolver);
  77: 
  78:     /**
  79:      * Evaluates an XPath expression string and returns a result of the 
  80:      * specified type if possible.
  81:      * @param expression The XPath expression string to be parsed and 
  82:      *   evaluated.
  83:      * @param contextNode The <code>context</code> is context node for the 
  84:      *   evaluation of this XPath expression. If the XPathEvaluator was 
  85:      *   obtained by casting the <code>Document</code> then this must be 
  86:      *   owned by the same document and must be a <code>Document</code>, 
  87:      *   <code>Element</code>, <code>Attribute</code>, <code>Text</code>, 
  88:      *   <code>CDATASection</code>, <code>Comment</code>, 
  89:      *   <code>ProcessingInstruction</code>, or <code>XPathNamespace</code> 
  90:      *   node. If the context node is a <code>Text</code> or a 
  91:      *   <code>CDATASection</code>, then the context is interpreted as the 
  92:      *   whole logical text node as seen by XPath, unless the node is empty 
  93:      *   in which case it may not serve as the XPath context.
  94:      * @param resolver The <code>resolver</code> permits translation of all 
  95:      *   prefixes, including the <code>xml</code> namespace prefix, within 
  96:      *   the XPath expression into appropriate namespace URIs. If this is 
  97:      *   specified as <code>null</code>, any namespace prefix within the 
  98:      *   expression will result in <code>DOMException</code> being thrown 
  99:      *   with the code <code>NAMESPACE_ERR</code>.
 100:      * @param type If a specific <code>type</code> is specified, then the 
 101:      *   result will be returned as the corresponding type.For XPath 1.0 
 102:      *   results, this must be one of the codes of the 
 103:      *   <code>XPathResult</code> interface.
 104:      * @param result The <code>result</code> specifies a specific result 
 105:      *   object which may be reused and returned by this method. If this is 
 106:      *   specified as <code>null</code>or the implementation does not reuse 
 107:      *   the specified result, a new result object will be constructed and 
 108:      *   returned.For XPath 1.0 results, this object will be of type 
 109:      *   <code>XPathResult</code>.
 110:      * @return The result of the evaluation of the XPath expression.For XPath 
 111:      *   1.0 results, this object will be of type <code>XPathResult</code>.
 112:      * @exception XPathException
 113:      *   INVALID_EXPRESSION_ERR: Raised if the expression is not legal 
 114:      *   according to the rules of the <code>XPathEvaluator</code>i
 115:      *   <br>TYPE_ERR: Raised if the result cannot be converted to return the 
 116:      *   specified type.
 117:      * @exception DOMException
 118:      *   NAMESPACE_ERR: Raised if the expression contains namespace prefixes 
 119:      *   which cannot be resolved by the specified 
 120:      *   <code>XPathNSResolver</code>.
 121:      *   <br>WRONG_DOCUMENT_ERR: The Node is from a document that is not 
 122:      *   supported by this <code>XPathEvaluator</code>.
 123:      *   <br>NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath 
 124:      *   context node or the request type is not permitted by this 
 125:      *   <code>XPathEvaluator</code>.
 126:      */
 127:     public Object evaluate(String expression, 
 128:                            Node contextNode, 
 129:                            XPathNSResolver resolver, 
 130:                            short type, 
 131:                            Object result)
 132:                            throws XPathException, DOMException;
 133: 
 134: }