org.apache.xpath.operations
Class Variable

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.apache.xpath.operations.Variable

public class Variable

extends Expression

The variable reference expression executer.

See Also:

Serialized Form

Constructor Summary

Variable()

Method Summary

XObject	execute(XPathContext xctxt) Dereference the variable, and return the reference value.
void	fixupVariables(java.util.Vector vars, int globalsSize) This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
boolean	isStableNumber() Tell if this expression returns a stable number that will not change during iterations within the expression.
void	setQName(QName qname) Set the qualified name of the variable.

Methods inherited from class org.apache.xpath.Expression

asIterator, asNode, assertion, bool, canTraverseOutsideSubtree, error, execute, execute, executeCharsToContentHandler, isNodesetExpr, num, setSourceLocator, warn, xstr

Methods inherited from class java.lang.Object

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

Constructor Detail

Variable

public Variable()

Method Detail

fixupVariables

public void fixupVariables(java.util.Vector vars,
                           int globalsSize)

This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.

Parameters:

vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame).

Overrides:

fixupVariables in class Expression

setQName

public void setQName(QName qname)

Set the qualified name of the variable.

Parameters:

qname - Must be a non-null reference to a qualified name.

execute

public XObject execute(XPathContext xctxt)
                throws javax.xml.transform.TransformerException

Dereference the variable, and return the reference value. Note that lazy evaluation will occur. If a variable within scope is not found, a warning will be sent to the error listener, and an empty nodeset will be returned.

Parameters:

xctxt - The runtime execution context.

Returns:

The evaluated variable, or an empty nodeset if not found.

Throws:

javax.xml.transform.TransformerException -

Overrides:

execute in class Expression

isStableNumber

public boolean isStableNumber()

Tell if this expression returns a stable number that will not change during iterations within the expression. This is used to determine if a proximity position predicate can indicate that no more searching has to occur.

Returns:

true if the expression represents a stable number.

Overrides:

isStableNumber in class Expression