org.apache.xpath.operations

Class Operation

Implemented Interfaces:
ExpressionNode, ExpressionOwner, java.io.Serializable, SourceLocator, XPathVisitable
Known Direct Subclasses:
And, Div, Equals, Gt, Gte, Lt, Lte, Minus, Mod, Mult, NotEquals, Or, Plus, Quo

public class Operation
extends Expression
implements ExpressionOwner

The baseclass for a binary operation.
See Also:
Serialized Form

Method Summary

void
callVisitors(ExpressionOwner owner, XPathVisitor visitor)
boolean
canTraverseOutsideSubtree()
Tell if this expression or it's subexpressions can traverse outside the current subtree.
boolean
deepEquals(Expression expr)
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
getExpression()
Expression
getLeftOperand()
Expression
getRightOperand()
XObject
operate(XObject left, XObject right)
Apply the operation to two operands, and return the result.
void
setExpression(Expression exp)
void
setLeftRight(Expression l, Expression r)
Set the left and right operand expressions for this operation.

Methods inherited from class org.apache.xpath.Expression

asIterator, asIteratorRaw, asNode, assertion, bool, canTraverseOutsideSubtree, deepEquals, error, execute, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, fixupVariables, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr

Method Details

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)
Specified by:
callVisitors in interface XPathVisitable

canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()
Tell if this expression or it's subexpressions can traverse outside the current subtree.
Overrides:
canTraverseOutsideSubtree in interface Expression
Returns:
true if traversal outside the context node's subtree can occur.

deepEquals

public boolean deepEquals(Expression expr)
Overrides:
deepEquals in interface Expression

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.
Overrides:
execute in interface Expression
Parameters:
xctxt - The runtime execution context.
Returns:
The XObject result of the operation.

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.
Overrides:
fixupVariables in interface Expression
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).

getExpression

public Expression getExpression()
Specified by:
getExpression in interface ExpressionOwner

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.

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.

setExpression

public void setExpression(Expression exp)
Specified by:
setExpression in interface ExpressionOwner

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.

Copyright B) 2005 Apache XML Project. All Rights Reserved.