org.apache.xpath.operations
Class UnaryOperation

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

Direct Known Subclasses:

Bool, Neg, Number, String

public abstract class UnaryOperation

extends Expression

The unary operation base class.

See Also:

Serialized Form

Constructor Summary

UnaryOperation()

Method Summary

boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
XObject	execute(XPathContext xctxt) Execute the operand and apply the unary operation to the result.
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.
Expression	getOperand()
abstract XObject	operate(XObject right) Apply the operation to two operands, and return the result.
void	setRight(Expression r) Set the expression operand for the operation.

Methods inherited from class org.apache.xpath.Expression

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

Methods inherited from class java.lang.Object

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

Constructor Detail

UnaryOperation

public UnaryOperation()

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

canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()

Tell if this expression or it's subexpressions can traverse outside the current subtree.

Returns:

true if traversal outside the context node's subtree can occur.

Overrides:

canTraverseOutsideSubtree in class Expression

setRight

public void setRight(Expression r)

Set the expression operand for the operation.

Parameters:

r - The expression operand to which the unary operation will be applied.

execute

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

Execute the operand and apply the unary operation to the result.

Parameters:

xctxt - The runtime execution context.

Returns:

An XObject that represents the result of applying the unary operation to the evaluated operand.

Throws:

javax.xml.transform.TransformerException -

Overrides:

execute in class Expression

operate

public abstract XObject operate(XObject right)
                         throws javax.xml.transform.TransformerException

Apply the operation to two operands, and return the result.

Parameters:

right - non-null reference to the evaluated right operand.

Returns:

non-null reference to the XObject that represents the result of the operation.

Throws:

javax.xml.transform.TransformerException -

getOperand

public Expression getOperand()

Returns:

the operand of unary operation, as an Expression.