org.apache.xpath.domapi
Class XPathEvaluatorImpl
java.lang.Object
org.apache.xpath.domapi.XPathEvaluatorImpl
- XPathEvaluator
public final class XPathEvaluatorImpl
extends java.lang.Object
implements XPathEvaluator
The class provides an implementation of XPathEvaluator according
to the DOM L3 XPath Specification, Working Group Note 26 February 2004.
See also the
Document Object Model (DOM) Level 3 XPath Specification.
The evaluation of XPath expressions is provided by
XPathEvaluator
, which will provide evaluation of XPath 1.0
expressions with no specialized extension functions or variables. It is
expected that the
XPathEvaluator
interface will be
implemented on the same object which implements the
Document
interface in an implementation which supports the XPath DOM module.
XPathEvaluator
implementations may be available from other
sources that may provide support for special extension functions or
variables which are not defined in this specification.
org.w3c.dom.xpath.XPathEvaluator
XPathEvaluatorImpl() - Constructor in the case that the XPath expression can be evaluated
without needing an XML document at all.
|
XPathEvaluatorImpl(Document doc) - Constructor for XPathEvaluatorImpl.
|
XPathExpression | createExpression(String expression, XPathNSResolver resolver) - Creates a parsed XPath expression with resolved namespaces.
|
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.
|
Object | evaluate(String expression, Node contextNode, XPathNSResolver resolver, short type, Object result) - Evaluates an XPath expression string and returns a result of the
specified type if possible.
|
XPathEvaluatorImpl
public XPathEvaluatorImpl()
Constructor in the case that the XPath expression can be evaluated
without needing an XML document at all.
XPathEvaluatorImpl
public XPathEvaluatorImpl(Document doc)
Constructor for XPathEvaluatorImpl.
doc
- The document to be searched, to parallel the case where''
the XPathEvaluator is obtained by casting the document.
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
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
.
- The compiled form of the XPath expression.
org.w3c.dom.xpath.XPathEvaluator.createExpression(String, 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.
org.w3c.dom.xpath.XPathEvaluator.createNSResolver(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
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
.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
.result
- The result
specifies a specific result
object which may be reused and returned by this method. If this is
specified as null
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
XPathResult
.
- The result of the evaluation of the XPath expression.For XPath
1.0 results, this object will be of type
XPathResult
.
org.w3c.dom.xpath.XPathEvaluator.evaluate(String, Node, XPathNSResolver, short, XPathResult)
Copyright B) 2005 Apache XML Project. All Rights Reserved.