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: Class ContextNodeExpression

com.icl.saxon.expr
Class ContextNodeExpression


java.lang.Object

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  +--com.icl.saxon.expr.Expression

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        +--com.icl.saxon.expr.NodeSetExpression

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              +--com.icl.saxon.expr.SingletonExpression

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                    +--com.icl.saxon.expr.ContextNodeExpression


public final class ContextNodeExpression
extends SingletonExpression

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


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.
Overrides:
getNode in class SingletonExpression
Parameters:
context - The context for the evaluation
Returns:
one NodeInfo only, namely the current node defined by the context

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
Overrides:
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.
Overrides:
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

display


public void display(int level)
Diagnostic print of expression structure
Overrides:
display in class Expression