org.w3c.dom.xpath
Interface XPathEvaluator
The evaluation of XPath expressions is provided by
XPathEvaluator. In a DOM implementation which supports the
XPath 3.0 feature, as described above, the
XPathEvaluator
interface will be implemented on the same object which implements the
Document 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.
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.
See also the
Document Object Model (DOM) Level 3 XPath Specification.
createExpression
public XPathExpression createExpression(String expression,
XPathNSResolver resolver)
throws XPathException,
DOMException 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.
expression - The XPath expression string to be parsed.resolver - 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 DOMException being thrown
with the code NAMESPACE_ERR.
- The compiled form of the XPath expression.
XPathException - INVALID_EXPRESSION_ERR: Raised if the expression is not legal
according to the rules of the XPathEvaluator.DOMException - NAMESPACE_ERR: Raised if the expression contains namespace prefixes
which cannot be resolved by the specified
XPathNSResolver.
createNSResolver
public XPathNSResolver createNSResolver(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.
nodeResolver - The node to be used as a context for namespace
resolution.
XPathNSResolver which resolves namespaces with
respect to the definitions in scope for a specified node.
evaluate
public Object evaluate(String expression,
Node contextNode,
XPathNSResolver resolver,
short type,
Object result)
throws XPathException,
DOMException Evaluates an XPath expression string and returns a result of the
specified type if possible.
expression - The XPath expression string to be parsed and
evaluated.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.resolver - 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 DOMException being thrown
with the code NAMESPACE_ERR.type - 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
XPathResult interface.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.
- The result of the evaluation of the XPath expression.For XPath
1.0 results, this object will be of type
XPathResult.
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.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 or the request type is not permitted by this
XPathEvaluator.
* 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