org.apache.xpath.domapi
public final class XPathEvaluatorImpl extends Object implements XPathEvaluator
See also the Document Object Model (DOM) Level 3 XPath Specification.
The evaluation of XPath expressions is provided byXPathEvaluator
, 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.
See Also: org.w3c.dom.xpath.XPathEvaluator
UNKNOWN: internal
Constructor Summary | |
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XPathEvaluatorImpl(Document doc)
Constructor for XPathEvaluatorImpl.
| |
XPathEvaluatorImpl()
Constructor in the case that the XPath expression can be evaluated
without needing an XML document at all.
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Method Summary | |
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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.
|
Parameters: doc The document to be searched, to parallel the case where'' the XPathEvaluator is obtained by casting the document.
Parameters: 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
.
Returns: The compiled form of the XPath expression.
Throws: XPathException
INVALID_EXPRESSION_ERR: Raised if the expression is not legal
according to the rules of the XPathEvaluator
i DOMException
NAMESPACE_ERR: Raised if the expression contains namespace prefixes
which cannot be resolved by the specified
XPathNSResolver
.
See Also: org.w3c.dom.xpath.XPathEvaluator#createExpression(String, XPathNSResolver)
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.
Parameters: nodeResolver The node to be used as a context for namespace resolution.
Returns: XPathNSResolver
which resolves namespaces with
respect to the definitions in scope for a specified node.
See Also: org.w3c.dom.xpath.XPathEvaluator#createNSResolver(Node)
Parameters: 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
.
Returns: The result of the evaluation of the XPath expression.For XPath
1.0 results, this object will be of type XPathResult
.
Throws: XPathException
INVALID_EXPRESSION_ERR: Raised if the expression is not legal
according to the rules of the XPathEvaluator
i
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.
See Also: org.w3c.dom.xpath.XPathEvaluator#evaluate(String, Node, XPathNSResolver, short, XPathResult)