uk.org.ogsadai.dqp.lqp.operators
Class SetOperator

java.lang.Object
  uk.org.ogsadai.dqp.lqp.operators.AbstractOperator
      uk.org.ogsadai.dqp.lqp.operators.BinaryOperator
          uk.org.ogsadai.dqp.lqp.operators.SetOperator

All Implemented Interfaces:

Annotatable, Operator

Direct Known Subclasses:

DifferenceOperator, IntersectionOperator, OuterUnionOperator, UnionOperator

public abstract class SetOperator
extends BinaryOperator

Abstract base class for set operators.

Author:

The OGSA-DAI Project Team.

Field Summary

protected boolean

mBagOperator Not a bag operator.

Fields inherited from class uk.org.ogsadai.dqp.lqp.operators.BinaryOperator

mCorrelatedAttributes, mLeftChildOperator, mRightChildOperator

Fields inherited from class uk.org.ogsadai.dqp.lqp.operators.AbstractOperator

mAnnotations, mID, mOperatorHeading, mParentOperator

Constructor Summary

SetOperator()

Method Summary

boolean	isBagOperator() Checks if operator is a bag operator.
void	update() Operator forwards the update call to its children and updates itself.
void	validate() Operator forwards the validation call to its children and validates itself.

Methods inherited from class uk.org.ogsadai.dqp.lqp.operators.BinaryOperator

disconnect, getChild, getChildCount, getChildIndex, getResultCardinality, isBinary, replaceChild, setChild, toString

Methods inherited from class uk.org.ogsadai.dqp.lqp.operators.AbstractOperator

addAnnotation, getAnnotation, getAnnotations, getHeading, getID, getParent, getUsedAttributes, isPartitionLeaf, removeAnnotation, renameUsedAttributes, setHeading, setParent

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.org.ogsadai.dqp.lqp.Operator

accept

Field Detail

mBagOperator

protected boolean mBagOperator

Not a bag operator.

Constructor Detail

SetOperator

public SetOperator()

Method Detail

isBagOperator

public boolean isBagOperator()

Checks if operator is a bag operator.

Returns:

true if operator is a bag operator, false if it is a set operator

update

public void update()
            throws LQPException

Operator forwards the update call to its children and updates itself. Operators must be updated after each change of their children. Update usually involves (but is not limited to) rebuilding the operator heading.

Specified by:

update in interface Operator

Overrides:

update in class BinaryOperator

Throws:

LQPException - when update fails

validate

public void validate()
              throws LQPException

Operator forwards the validation call to its children and validates itself. Validation depends on operator logic. This usually involves (but is not limited to) checking if all attributes required to perform operator logic are in children's headings.

Specified by:

validate in interface Operator

Overrides:

validate in class BinaryOperator

Throws:

LQPException - when validation fails