weblogic.apache.xpath.operations
Class Operation

java.lang.Object
  |
  +--weblogic.apache.xpath.Expression
        |
        +--weblogic.apache.xpath.operations.Operation

Direct Known Subclasses:

And, Div, Equals, Gt, Gte, Lt, Lte, Minus, Mod, Mult, NotEquals, Or, Plus, Quo

public class Operation

extends Expression

The baseclass for a binary operation.

This class is based on an implementation from the Apache XML Project. In future releases the XML parser, XSLT processor, and associated classes will likely be updated to be based on a later version of the Apache implementations. Since Apache does not guarantee backwards compatibility between versions of their software, we cannot guarantee backwards compatibility of any of the classes contained in the weblogic.apache package or sub-packages.

See Also:

Serialized Form

Field Summary

protected Expression	m_left The left operand expression.
protected Expression	m_right The right operand expression.

Fields inherited from class weblogic.apache.xpath.Expression

m_slocator

Constructor Summary

Operation()

Method Summary

boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
XObject	execute(XPathContext xctxt) Execute a binary operation by calling execute on each of the operands, and then calling the operate method on the derived class.
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	getLeftOperand()
Expression	getRightOperand()
XObject	operate(XObject left, XObject right) Apply the operation to two operands, and return the result.
void	setLeftRight(Expression l, Expression r) Set the left and right operand expressions for this operation.

Methods inherited from class weblogic.apache.xpath.Expression

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

Methods inherited from class java.lang.Object

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

Field Detail

m_left

protected Expression m_left

The left operand expression.

m_right

protected Expression m_right

The right operand expression.

Constructor Detail

Operation

public Operation()

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

setLeftRight

public void setLeftRight(Expression l,
                         Expression r)

Set the left and right operand expressions for this operation.

Parameters:

l - The left expression operand.

r - The right expression operand.

execute

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

Execute a binary operation by calling execute on each of the operands, and then calling the operate method on the derived class.

Parameters:

xctxt - The runtime execution context.

Returns:

The XObject result of the operation.

Throws:

javax.xml.transform.TransformerException -

Overrides:

execute in class Expression

operate

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

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

Parameters:

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

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 -

getLeftOperand

public Expression getLeftOperand()

Returns:

the left operand of binary operation, as an Expression.

getRightOperand

public Expression getRightOperand()

Returns:

the right operand of binary operation, as an Expression.