org.apache.xpath.operations
Class Operation

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.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
implements ExpressionOwner

The baseclass for a binary operation.

See Also:
Serialized Form

Constructor Summary
Operation()
           
 
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, error, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

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 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:
TransformerException -  
Overrides:
execute in class Expression

operate

public XObject operate(XObject left,
                       XObject right)
                throws 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:
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.

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)
See Also:
XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)

getExpression

public Expression getExpression()
Specified by:
getExpression in interface ExpressionOwner
See Also:
ExpressionOwner.getExpression()

setExpression

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

deepEquals

public boolean deepEquals(Expression expr)
Overrides:
deepEquals in class Expression
See Also:
Expression.deepEquals(Expression)


Copyright 2006 Apache XML Project. All Rights Reserved.