com.icl.saxon.expr
Class VariableReference

java.lang.Object
  com.icl.saxon.expr.Expression
      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