org.jdom.xpath
public abstract class XPath extends Object implements Serializable
Version: $Revision: 1.17 $, $Date: 2007/11/10 05:29:02 $
Field Summary | |
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static String | JDOM_OBJECT_MODEL_URI
The string passable to the JAXP 1.3 XPathFactory isObjectModelSupported()
method to query an XPath engine regarding its support for JDOM. |
Method Summary | |
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abstract void | addNamespace(Namespace namespace)
Adds a namespace definition to the list of namespaces known of
this XPath expression.
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void | addNamespace(String prefix, String uri)
Adds a namespace definition (prefix and URI) to the list of
namespaces known of this XPath expression.
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abstract String | getXPath()
Returns the wrapped XPath expression as a string.
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static XPath | newInstance(String path)
Creates a new XPath wrapper object, compiling the specified
XPath expression.
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abstract Number | numberValueOf(Object context)
Returns the number value of the first node selected by applying
the wrapped XPath expression to the given context.
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abstract List | selectNodes(Object context)
Evaluates the wrapped XPath expression and returns the list
of selected items.
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static List | selectNodes(Object context, String path)
Evaluates an XPath expression and returns the list of selected
items.
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abstract Object | selectSingleNode(Object context)
Evaluates the wrapped XPath expression and returns the first
entry in the list of selected nodes (or atomics).
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static Object | selectSingleNode(Object context, String path)
Evaluates the wrapped XPath expression and returns the first
entry in the list of selected nodes (or atomics).
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abstract void | setVariable(String name, Object value)
Defines an XPath variable and sets its value.
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static void | setXPathClass(Class aClass)
Sets the concrete XPath subclass to use when allocating XPath
instances.
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abstract String | valueOf(Object context)
Returns the string value of the first node selected by applying
the wrapped XPath expression to the given context.
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protected Object | writeReplace()
[Serialization support] Returns the alternative object
to write to the stream when serializing this object. |
Note: In XPath, there is no such thing as a 'default namespace'. The empty prefix always resolves to the empty namespace URI.
Parameters: namespace the namespace.
Note: In XPath, there is no such thing as a 'default namespace'. The empty prefix always resolves to the empty namespace URI.
Parameters: prefix the namespace prefix. uri the namespace URI.
Throws: IllegalNameException if the prefix or uri are null or empty strings or if they contain illegal characters.
Returns: the wrapped XPath expression as a string.
Parameters: path the XPath expression to wrap.
Throws: JDOMException if the XPath expression is invalid.
Parameters: context the element to use as context for evaluating the XPath expression.
Returns: the number value of the first node selected by applying
the wrapped XPath expression to the given context,
null
if no node was selected or the
special value java.lang.Double#NaN
(Not-a-Number) if the selected value can not be
converted into a number value.
Throws: JDOMException if the XPath expression is invalid or its evaluation on the specified context failed.
Parameters: context the node to use as context for evaluating the XPath expression.
Returns: the list of selected items, which may be of types: Element, Attribute, Text, CDATA, Comment, ProcessingInstruction, Boolean, Double, or String.
Throws: JDOMException if the evaluation of the XPath expression on the specified context failed.
Note: This method should not be used when the
same XPath expression needs to be applied several times (on the
same or different contexts) as it requires the expression to be
compiled before being evaluated. In such cases,
allocating
an XPath wrapper instance and
evaluating
it several
times is way more efficient.
Parameters: context the node to use as context for evaluating the XPath expression. path the XPath expression to evaluate.
Returns: the list of selected items, which may be of types: Element, Attribute, Text, CDATA, Comment, ProcessingInstruction, Boolean, Double, or String.
Throws: JDOMException if the XPath expression is invalid or its evaluation on the specified context failed.
Parameters: context the node to use as context for evaluating the XPath expression.
Returns: the first selected item, which may be of types: Element,
Attribute, Text, CDATA,
Comment, ProcessingInstruction, Boolean,
Double, String, or null
if no item was selected.
Throws: JDOMException if the evaluation of the XPath expression on the specified context failed.
Note: This method should not be used when the
same XPath expression needs to be applied several times (on the
same or different contexts) as it requires the expression to be
compiled before being evaluated. In such cases,
allocating
an XPath wrapper instance and
evaluating
it
several times is way more efficient.
Parameters: context the element to use as context for evaluating the XPath expression. path the XPath expression to evaluate.
Returns: the first selected item, which may be of types: Element,
Attribute, Text, CDATA,
Comment, ProcessingInstruction, Boolean,
Double, String, or null
if no item was selected.
Throws: JDOMException if the XPath expression is invalid or its evaluation on the specified context failed.
Parameters: name the variable name. value the variable value.
Throws: IllegalArgumentException if name
is not
a valid XPath variable name
or if the value type is not
supported by the underlying
implementation
Parameters: aClass the concrete subclass of XPath.
Throws: IllegalArgumentException if aClass
is
null
. JDOMException if aClass
is
not a concrete subclass
of XPath.
Parameters: context the element to use as context for evaluating the XPath expression.
Returns: the string value of the first node selected by applying the wrapped XPath expression to the given context.
Throws: JDOMException if the XPath expression is invalid or its evaluation on the specified context failed.
Note: Subclasses are not allowed to override this method to ensure valid serialization of all implementations.
Returns: an XPathString instance configured with the wrapped XPath expression.
Throws: ObjectStreamException never.