File	Doc	Category	Size	Date	Package
XPathEvaluatorImpl.java	API Doc	Java SE 6 API	11259	Tue Jun 10 00:23:14 BST 2008	com.sun.org.apache.xpath.internal.domapi

XPathEvaluatorImpl

• java.lang.Object

Fields Summary
private final Document	m_doc The document to be searched to parallel the case where the XPathEvaluator is obtained by casting a Document.

Constructors Summary
public XPathEvaluatorImpl(Document doc) Constructor for XPathEvaluatorImpl. param doc The document to be searched, to parallel the case where'' the XPathEvaluator is obtained by casting the document. m_doc = doc;
public XPathEvaluatorImpl() Constructor in the case that the XPath expression can be evaluated without needing an XML document at all. m_doc = null;

Methods Summary
public org.w3c.dom.xpath.XPathExpression	createExpression(java.lang.String expression, org.w3c.dom.xpath.XPathNSResolver resolver) 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 resolver permits translation of prefixes within the XPath expression into appropriate namespace URIs . If this is specified as null, any namespace prefix within the expression will result in DOMException being thrown with the code NAMESPACE_ERR. 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 XPathEvaluatori exception DOMException NAMESPACE_ERR: Raised if the expression contains namespace prefixes which cannot be resolved by the specified XPathNSResolver. see org.w3c.dom.xpath.XPathEvaluator#createExpression(String, XPathNSResolver) try { // If the resolver is null, create a dummy prefix resolver XPath xpath = new XPath(expression,null, ((null == resolver) ? new DummyPrefixResolver() : ((PrefixResolver)resolver)), XPath.SELECT); return new XPathExpressionImpl(xpath, m_doc); } catch (TransformerException e) { // Need to pass back exception code DOMException.NAMESPACE_ERR also. // Error found in DOM Level 3 XPath Test Suite. if(e instanceof XPathStylesheetDOM3Exception) throw new DOMException(DOMException.NAMESPACE_ERR,e.getMessageAndLocation()); else throw new XPathException(XPathException.INVALID_EXPRESSION_ERR,e.getMessageAndLocation()); }
public org.w3c.dom.xpath.XPathNSResolver	createNSResolver(org.w3c.dom.Node nodeResolver) 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 The node to be used as a context for namespace resolution. return XPathNSResolver which resolves namespaces with respect to the definitions in scope for a specified node. see org.w3c.dom.xpath.XPathEvaluator#createNSResolver(Node) return new XPathNSResolverImpl((nodeResolver.getNodeType() == Node.DOCUMENT_NODE) ? ((Document) nodeResolver).getDocumentElement() : nodeResolver);
public java.lang.Object	evaluate(java.lang.String expression, org.w3c.dom.Node contextNode, org.w3c.dom.xpath.XPathNSResolver resolver, short type, java.lang.Object result) 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 context is context node for the evaluation of this XPath expression. If the XPathEvaluator was obtained by casting the Document then this must be owned by the same document and must be a Document, Element, Attribute, Text, CDATASection, Comment, ProcessingInstruction, or XPathNamespace node. If the context node is a Text or a CDATASection, 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 resolver permits translation of prefixes within the XPath expression into appropriate namespace URIs . If this is specified as null, any namespace prefix within the expression will result in DOMException being thrown with the code NAMESPACE_ERR. param type If a specific type 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 XPathResult. param result The result specifies a specific result object which may be reused and returned by this method. If this is specified as nullor 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 XPathResult. return The result of the evaluation of the XPath expression.For XPath 1.0 results, this object will be of type XPathResult. exception XPathException INVALID_EXPRESSION_ERR: Raised if the expression is not legal according to the rules of the XPathEvaluatori 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 XPathNSResolver. WRONG_DOCUMENT_ERR: The Node is from a document that is not supported by this XPathEvaluator. 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) XPathExpression xpathExpression = createExpression(expression, resolver); return xpathExpression.evaluate(contextNode, type, result);