countprojection.java

hibernate-distribution-3.3.1.GA-dist.zip源码

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.criterion;

import org.hibernate.Criteria;
import org.hibernate.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.type.Type;

/**
 * A count
 * @author Gavin King
 */
public class CountProjection extends AggregateProjection {

	private boolean distinct;

	protected CountProjection(String prop) {
		super("count", prop);
	}

	public String toString() {
		if(distinct) {
			return "distinct " + super.toString();
		} else {
			return super.toString();
		}
	}

	public Type[] getTypes(Criteria criteria, CriteriaQuery criteriaQuery) 
	throws HibernateException {
		return new Type[] { Hibernate.INTEGER };
	}

	public String toSqlString(Criteria criteria, int position, CriteriaQuery criteriaQuery) 
	throws HibernateException {
		StringBuffer buf = new StringBuffer();
		buf.append("count(");
		if (distinct) buf.append("distinct ");
		return buf.append( criteriaQuery.getColumn(criteria, propertyName) )
			.append(") as y")
			.append(position)
			.append('_')
			.toString();
	}
	
	public CountProjection setDistinct() {
		distinct = true;
		return this;
	}
	
}