/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jbpm.pvm.internal.query;
import java.io.ObjectStreamException;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.jbpm.api.JbpmException;
import org.jbpm.pvm.internal.cmd.Command;
import org.jbpm.pvm.internal.cmd.CommandService;
import org.jbpm.pvm.internal.env.Environment;
/**
* @author Tom Baeyens
*/
public abstract class AbstractQuery implements Command<Object> {
private static final long serialVersionUID = 1L;
protected CommandService commandService;
protected String orderByClause = null;
protected Page page = null;
protected boolean isWhereAdded = false;
protected abstract void applyParameters(Query query);
public abstract String hql();
/* reuse by copy and paste:
* (return type can't be changed)
public ConcreteQuery page(int firstResult, int maxResults) {
this.page = new Page(firstResult, maxResults);
return this;
}
*/
public List untypedList() {
if (commandService!=null) {
return (List) commandService.execute(this);
}
Session session = Environment.getFromCurrent(Session.class);
return (List) execute(session);
}
protected Object untypedUniqueResult() {
List list = untypedList();
if (list.isEmpty()) {
return null;
}
if (list.size()>1) {
throw new JbpmException("result not unique: "+list.size());
}
return list.get(0);
}
public Object execute(Environment environment) throws Exception {
Session session = environment.get(Session.class);
return execute(session);
}
public Object execute(Session session) {
String hql = hql();
Query query = session.createQuery(hql);
applyParameters(query);
applyPage(query);
return query.list();
}
protected void appendWhereClause(String whereClause, StringBuilder hql) {
if (isWhereAdded) {
hql.append(" and ");
} else {
isWhereAdded = true;
hql.append("where ");
}
hql.append(whereClause);
}
protected void appendOrderByClause(StringBuilder hql) {
if (orderByClause!=null) {
hql.append("order by ");
hql.append(orderByClause);
}
}
protected void applyPage(Query query) {
if (page!=null) {
query.setFirstResult(page.firstResult);
query.setMaxResults(page.maxResults);
}
}
protected void addOrderByClause(String clause) {
if (orderByClause==null) {
orderByClause = clause;
} else {
orderByClause += ", " + clause;
}
}
protected Object writeReplace() throws ObjectStreamException {
this.commandService = null;
return this;
}
public void setCommandService(CommandService commandService) {
this.commandService = commandService;
}
}