Java XPathExpression.evaluate方法代码示例

import org.w3c.dom.xpath.XPathExpression; //导入方法依赖的package包/类
/**
 * <b>DOM</b>: Implements
 * {@link org.w3c.dom.xpath.XPathEvaluator#evaluate(String,Node,XPathNSResolver,short,Object)}.
 */
public Object evaluate(String expression,
                       Node contextNode,
                       XPathNSResolver resolver,
                       short type,
                       Object result)
        throws XPathException, DOMException {
    XPathExpression xpath = createExpression(expression, resolver);
    return xpath.evaluate(contextNode, type, result);
}
 

import org.w3c.dom.xpath.XPathExpression; //导入方法依赖的package包/类
public Object evaluate(String expression,
                       Node contextNode,
                       XPathNSResolver resolver,
                       short type,
                       Object result)
  throws XPathException, DOMException
{
  XPathExpression xpe =
    new DomXPathExpression(this, expression, resolver);
  return xpe.evaluate(contextNode, type, result);
}
 

import org.w3c.dom.xpath.XPathExpression; //导入方法依赖的package包/类
/**
* 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
*   prefixes 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 coerced to return the specified type relying on
*   XPath type conversions and fail if the desired coercion is not
*   possible. This must be one of the type codes of
*   <code>XPathResult</code>.
* @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 XPathEvaluator.
*   <br>NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath
*   context node.
    *
    * @see org.w3c.dom.xpath.XPathEvaluator#evaluate(String, Node, XPathNSResolver, short, XPathResult)
    */
   public Object evaluate(
           String expression,
           Node contextNode,
           XPathNSResolver resolver,
           short type,
           Object result)
           throws XPathException, DOMException {

           XPathExpression xpathExpression = createExpression(expression, resolver);

           return  xpathExpression.evaluate(contextNode, type, result);
   }