/*
* Copyright 2009 Ralf Joachim, Ahmad Hassan
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.castor.cpa.persistence.sql.query.expression;
import org.castor.cpa.persistence.sql.query.QueryObject;
import org.castor.cpa.persistence.sql.query.condition.Compare;
import org.castor.cpa.persistence.sql.query.condition.CompareOperator;
import org.castor.cpa.persistence.sql.query.condition.IsNullPredicate;
import org.castor.cpa.persistence.sql.query.condition.Predicate;
/**
* Abstract base class for all expressions.
*
* @author <a href="mailto:ahmad DOT hassan AT gmail DOT com">Ahmad Hassan</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision$ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $
*/
public abstract class Expression implements QueryObject {
//-----------------------------------------------------------------------------------
/**
* Compare if this expression is equal to the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare equal(final Expression expression) {
return new Compare(this, CompareOperator.EQ, expression);
}
/**
* Compare if this expression is not equal to the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare notEqual(final Expression expression) {
return new Compare(this, CompareOperator.NE, expression);
}
/**
* Compare if this expression is greater than the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare greaterThan(final Expression expression) {
return new Compare(this, CompareOperator.GT, expression);
}
/**
* Compare if this expression is greater than or equal to the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare greaterEqual(final Expression expression) {
return new Compare(this, CompareOperator.GE, expression);
}
/**
* Compare if this expression is less than or equal to the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare lessEqual(final Expression expression) {
return new Compare(this, CompareOperator.LE, expression);
}
/**
* Compare if this expression is less than the given one.
*
* @param expression Right hand side of the compare.
* @return Compare condition.
*/
public final Compare lessThan(final Expression expression) {
return new Compare(this, CompareOperator.LT, expression);
}
/**
* Check if this expression is null.
*
* @return Compare condition.
*/
public final Predicate isNull() {
return new IsNullPredicate(this, true);
}
/**
* Check if this expression is not null.
*
* @return Compare condition.
*/
public final Predicate isNotNull() {
return new IsNullPredicate(this, false);
}
//-----------------------------------------------------------------------------------
}