Class XPathContext

java.lang.Object
org.exolab.adaptx.xpath.XPathContext
Direct Known Subclasses:
ProcessorState

public class XPathContext extends Object
Base implementation of an XPath context. An XPath context provides a way to manage a stack of node-sets, resolve variable and function names, and return the size and position of the 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.

Version:
$Revision: 3633 $
Author:
Keith Visco, Assaf Arkin
  • Constructor Details

    • XPathContext

      public XPathContext(XPathNode node)
      Constructs a new XPath context using the given node as the context node. The size is set to 1 and position is set to 0 and no variable bindings are provided.
      Parameters:
      node - the context XPathNode.
    • XPathContext

      public XPathContext(XPathNode node, VariableSet variables)
      Constructs a new XPath context using the given node as as the context node. The size is set to 1 and position is set to 0. Variables bindings may be optionally provided.
      Parameters:
      node - the context XPathNode.
      variable - Variable bindings, or null
    • XPathContext

      public XPathContext(VariableSet variables, NodeSet nodeSet, int position)
      Constructs a new XPath context. Variables bindings may be optionally provided, size and position are required.
      Parameters:
      nodeSet - the context node-set for this XPathContext
      position - The position of the context node (zero base)
      variable - Variable bindings, or null
  • Method Details

    • addNamespaceBinding

      public void addNamespaceBinding(String prefix, String namespace)
      Creates a binding within this XPathContext between a given prefix and a namespace URI. This namespace binding will be override any binding for the given prefix within a parent context, and will be available to all sub-contexts unless they also override the namespace binding with one of their own.
      Parameters:
      prefix - the prefix to associate with the namespace
      namespace - the namespace URI.
    • getNode

      public XPathNode getNode()
      Returns the context node of this XPathContext
      Returns:
      the context node
    • getPosition

      public int getPosition()
      Returns the position of the context node. The position is a value between zero and the context size minus one. One must be added in order to obtain a value XPath position.
      Returns:
      The position of the context node
      See Also:
    • getSize

      public int getSize()
      Returns the size of the context.
      Returns:
      The size of the context
    • newContext

      public XPathContext newContext(XPathNode node)
      Creates a new XPathContext with this XPathContext as it's parent.
      Returns:
      the new XPathContext
    • newContext

      public XPathContext newContext(NodeSet nodeSet, int position)
      Creates a new XPathContext with this XPathContext as it's parent.
      Returns:
      the new XPathContext
    • newNodeSet

      public NodeSet newNodeSet(int size)
      Constructs and returns a new node-set with the specified size.
      Parameters:
      size - The size of the node-set
      Returns:
      A new node-set with that size
    • newNodeSet

      public NodeSet newNodeSet(XPathNode node)
      Constructs and returns a new node-set with one node.
      Parameters:
      node - The node to include in the node-set
      Returns:
      A new node-set
    • newNodeSet

      public NodeSet newNodeSet()
      Constructs and returns a new empty node-set.
      Returns:
      A new empty node-set
    • getNodeSet

      public NodeSet getNodeSet()
      Returns the current context node-set.
      Returns:
      The current context node-set
    • setNodeSet

      public void setNodeSet(NodeSet nodeSet, int position)
      Sets the given node-set as the context node-set for this XPathContext
      Parameters:
      nodeSet - the node-set to use as the context node-set.
      position - the position of the context node
    • getDocumentOrder

      public int[] getDocumentOrder(XPathNode node)
      Returns the document order of the given node.
      Returns:
      The document order of the given node
    • getElementById

      public XPathNode getElementById(XPathNode root, String id)
      Returns the element associated with the given identifier. Locates the element underneath the specified root node.
      Parameters:
      root - The root node
      id - The element's identifier
      Returns:
      The first element in document order with the given identifier, or null if no such element was found
    • getVariable

      public XPathResult getVariable(String name)
      Returns the XPath result bound to the given variable name. Returns null if the variable was not set.
      Parameters:
      name - The variable name
      Returns:
      The variable's value
    • getFunction

      public XPathFunction getFunction(String uri, String name)
      Returns the XPath function by the given name, or null if no such function is defined.
      Parameters:
      uri - The function's namespace URI
      name - The function's name within that URI
      Returns:
      The XPath function by the given name, or null if no such function is defined
    • getNamespaceURI

      public String getNamespaceURI(String prefix)
      Returns the namespace associated with the given prefix as defined in this context. Null is returned if no namespace has been defined.
      Parameters:
      prefix - the namespace prefix
      Returns:
      the namespace uri or null.
    • setPosition

      public void setPosition(int position)
      Sets the position of the context node within the context node-set
      Parameters:
      the - position of the context node within the context node-set
      Throws:
      IndexOutOfBoundsException - when the position is not within the bounds of the context node-set.