Package org.exolab.adaptx.xpath
XPath API
- Version:
- $Revision: 3633 $ $Date: 2003-03-01 08:38:44 +0100 (Sat, 01 Mar 2003) $
- Author:
- Keith Visco
- Author:
- Assaf Arkin
Expressions And Results
An XPath expression is compiled using the XPath parser. To obtain a new parser instance
use the static method newInstance
.
Once obtained, the parser can be used to create XPath expressions using the createExpression
method. Expressions
are compiled and can be reused multiple times. The parser is thread-safe and can be
used to create multiple expressions concurrently.
com.intalio.n3.xpath.XPathExpression
is an abstract class representing an
XPath expression. The primary method is evaluate
that is used to evaluates the expression and returns the XPath result.
An XPath result is represented by the abstract class com.intalio.n3.xpath.XPathResult
.
An XPath result can be one of the following four types:
- A boolean result of type
com.intalio.n3.xpath.XPathResult#BOOLEAN
represented by an object of typecom.intalio.n3.xpath.BooleanResult
. - A string result of type
com.intalio.n3.xpath.XPathResult#STRING
represented by an object of typecom.intalio.n3.xpath.StringResult
. - A number result of type
com.intalio.n3.xpath.XPathResult#NUMBER
represented by an object of typecom.intalio.n3.xpath.NumberResult
. - A node-set result of type
com.intalio.n3.xpath.XPathResult#NODE_SET
represented by an object of typecom.intalio.n3.xpath.NodeSet
.
XPath Context
In order to evaluate an XPath expression, an XPath context is required. An XPath context
provides a way to manage a stock of node-sets, resolve variable and function names, and
return the size and position of the context. com.intalio.n3.xpath.XPathContext
provides a base implementation of an XPath context. This implementation is not thread-safe,
care must be taken not to use the same context when evaluating expressions concurrently.
Impelementations may wish to extend this class and provide additional facilities
for locating the document order of a node, or providing a function library.
com.intalio.n3.xpath.Variables
provides variable bindings that can be used when
evaluating an XPath expression, and com.intalio.n3.xpath.XPathFunction
can be used
to implement extension functions.
XPath Node
com.intalio.n3.xpath.XPathNode
is an abstract class representing a node in
a document tree, on which XPath expressions can be evaluated. This abstract class provides
all the services required by XPath, and enables multiple implementations to exist.
It does not make use of iterators or traversals, but assumes double-linked lists are
used to maintain node lists.
-
Interface Summary Interface Description Parameters A class for representing function parameters.XPathExpression Interface representing an XPath expression. -
Class Summary Class Description BooleanResult Represents a boolean result.FunctionState A class for holding onto state information for extension function calls, such as the funciton parameters.NodeSet Represents a node-set.NumberResult Represents a number result.StringResult Represents a string result.VariableSet An abstract class which allows the use of variables when evaluating XPath expressions.VariableSetImpl An implementation of VariableSet which is used to provide variable bindings that can be used when evaluating an XPath expression.XPathContext Base implementation of an XPath context.XPathFunction Abstract class representing an XPath function.XPathNode Abstract class representing a node in a document tree, on which XPath expressions can be evaluated.XPathParser The XPath parser.XPathResult Abstract class representing the result of an XPath expression. -
Exception Summary Exception Description XPathException Indicates an error occured while evaluating an XPath expression.