com.icl.saxon.expr
Class ContextNodeExpression

java.lang.Object
  com.icl.saxon.expr.Expression
      com.icl.saxon.expr.NodeSetExpression
          com.icl.saxon.expr.SingletonExpression
              com.icl.saxon.expr.ContextNodeExpression

public final class ContextNodeExpression

extends SingletonExpression

This class represents the expression ".", which always returns the context node.

Field Summary

Fields inherited from class com.icl.saxon.expr.Expression

staticContext

Constructor Summary

ContextNodeExpression()

Method Summary

void	display(int level) Diagnostic print of expression structure
int	getDependencies() Determine which aspects of the context the expression depends on.
NodeInfo	getNode(Context context) Return the node selected by this expression.
Expression	reduce(int dependencies, Context context) Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.

Methods inherited from class com.icl.saxon.expr.SingletonExpression

enumerate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsString, isContextDocumentNodeSet, selectFirst

Methods inherited from class com.icl.saxon.expr.NodeSetExpression

evaluate, getDataType, outputStringValue

Methods inherited from class com.icl.saxon.expr.Expression

containsReferences, evaluateAsNumber, getStaticContext, indent, make, setStaticContext, simplify, usesCurrent

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ContextNodeExpression

public ContextNodeExpression()

Method Detail

getNode

public NodeInfo getNode(Context context)
                 throws XPathException

Return the node selected by this expression.

Specified by:

getNode in class SingletonExpression

Parameters:

context - The context for the evaluation

Returns:

one NodeInfo only, namely the current node defined by the context

Throws:

XPathException

getDependencies

public int getDependencies()

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE

Specified by:

getDependencies in class Expression

reduce

public Expression reduce(int dependencies,
                         Context context)
                  throws XPathException

Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.

Specified by:

reduce in class Expression

Parameters:

dependencies - The dependencies to be removed

context - The context to be used for the partial evaluation

Returns:

a new expression that does not have any of the specified dependencies

Throws:

XPathException

display

public void display(int level)

Diagnostic print of expression structure

Specified by:

display in class Expression