com.icl.saxon.expr
Class VariableReference

java.lang.Object
  extended by com.icl.saxon.expr.Expression
      extended by com.icl.saxon.expr.VariableReference

public class VariableReference
extends Expression

Variable reference: a reference to an XSL variable


Field Summary
(package private)  Binding binding
           
(package private)  int fingerprint
           
 
Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
VariableReference(int fingerprint, StaticContext staticContext)
          Constructor
 
Method Summary
 void display(int level)
          Diagnostic print of expression structure
 Value evaluate(Context c)
          Get the value of this variable in a given context.
 Binding getBinding()
          Get the object bound to the variable
 int getDataType()
          Determine the data type of the expression, if possible
 int getDependencies()
          Determine which aspects of the context the expression depends on.
 Expression reduce(int dependencies, Context context)
          Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
 Expression simplify()
          Simplify the expression.
 
Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, enumerate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

fingerprint

int fingerprint

binding

Binding binding
Constructor Detail

VariableReference

public VariableReference(int fingerprint,
                         StaticContext staticContext)
                  throws XPathException
Constructor

Parameters:
name - the variable name (as a Name object)
Throws:
XPathException
Method Detail

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

evaluate

public Value evaluate(Context c)
               throws XPathException
Get the value of this variable in a given context.

Specified by:
evaluate in class Expression
Parameters:
context - the Context which contains the relevant variable bindings
Returns:
the value of the variable, if it is defined
Throws:
XPathException

getBinding

public Binding getBinding()
Get the object bound to the variable


getDataType

public int getDataType()
Determine the data type of the expression, if possible

Specified by:
getDataType in class Expression
Returns:
the type of the variable, if this can be determined statically; otherwise Value.ANY (meaning not known in advance)

simplify

public Expression simplify()
Simplify the expression. If the variable has a fixed value, the variable reference will be replaced with that value.

Overrides:
simplify in class Expression
Returns:
the simplified expression

display

public void display(int level)
Diagnostic print of expression structure

Specified by:
display in class Expression