org.apache.xpath.operations
Class Operation

java.lang.Object
  org.apache.xpath.Expression
      org.apache.xpath.operations.Operation

All Implemented Interfaces:

ExpressionNode, ExpressionOwner, Serializable, javax.xml.transform.SourceLocator, XPathVisitable

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

Nested Class Summary

(package private) class

Operation.LeftExprOwner

Field Summary

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

Fields inherited from class org.apache.xpath.Expression

Constructor Summary

Operation()

Method Summary

void	callVisitors(ExpressionOwner owner, XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
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(Vector vars, int globalsSize) This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
Expression	getExpression() Get the raw Expression object that this class wraps.
Expression	getLeftOperand()
Expression	getRightOperand()
XObject	operate(XObject left, XObject right) Apply the operation to two operands, and return the result.
void	setExpression(Expression exp) Set the raw expression object for this object.
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, isSameClass, isStableNumber, num, 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(Vector vars,
                           int globalsSize)

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

Specified by:

fixupVariables in class 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).

canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()

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

Overrides:

canTraverseOutsideSubtree in class Expression

Returns:

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

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.

Specified by:

execute in class Expression

Parameters:

xctxt - The runtime execution context.

Returns:

The XObject result of the operation.

Throws:

javax.xml.transform.TransformerException

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.

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)

Description copied from interface: XPathVisitable

This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Specified by:

callVisitors in interface XPathVisitable

Parameters:

owner - The owner of the visitor, where that path may be rewritten if needed.

visitor - The visitor whose appropriate method will be called.

See Also:

XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)

getExpression

public Expression getExpression()

Description copied from interface: ExpressionOwner

Get the raw Expression object that this class wraps.

Specified by:

getExpression in interface ExpressionOwner

Returns:

the raw Expression object, which should not normally be null.

See Also:

ExpressionOwner.getExpression()

setExpression

public void setExpression(Expression exp)

Description copied from interface: ExpressionOwner

Set the raw expression object for this object.

Specified by:

setExpression in interface ExpressionOwner

Parameters:

exp - the raw Expression object, which should not normally be null.

See Also:

ExpressionOwner.setExpression(Expression)

deepEquals

public boolean deepEquals(Expression expr)

Description copied from class: Expression

Compare this object with another object and see if they are equal, include the sub heararchy.

Specified by:

deepEquals in class Expression

Parameters:

expr - Another expression object.

Returns:

true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.

See Also:

Expression.deepEquals(Expression)