Java tutorial
/* * Copyright 2008 Jeff Dwyer * * 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 com.apress.progwt.server.dao.hibernate; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import org.apache.log4j.Logger; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.criterion.DetachedCriteria; import org.hibernate.criterion.Expression; import org.hibernate.criterion.MatchMode; import org.hibernate.criterion.Order; import org.hibernate.criterion.Projections; import org.springframework.dao.support.DataAccessUtils; import org.springframework.orm.hibernate3.HibernateCallback; import org.springframework.orm.hibernate3.support.HibernateDaoSupport; import com.apress.progwt.client.domain.Application; import com.apress.progwt.client.domain.ForumPost; import com.apress.progwt.client.domain.Loadable; import com.apress.progwt.client.domain.ProcessType; import com.apress.progwt.client.domain.RatingType; import com.apress.progwt.client.domain.School; import com.apress.progwt.client.domain.SchoolForumPost; import com.apress.progwt.client.domain.User; import com.apress.progwt.client.domain.UserForumPost; import com.apress.progwt.client.domain.dto.PostsList; import com.apress.progwt.server.dao.SchoolDAO; public class SchoolDAOHibernateImpl extends HibernateDaoSupport implements SchoolDAO { private int autoCompleteMax = 7; private static final Logger log = Logger.getLogger(SchoolDAOHibernateImpl.class); public Loadable get(Class<? extends Loadable> loadable, Long id) { return (Loadable) getHibernateTemplate().get(loadable, id); } public List<School> getAllSchools(int start, int max) { DetachedCriteria crit = DetachedCriteria.forClass(School.class).addOrder(Order.desc("popularityCounter")); // .add( // Expression.and(Expression.gt("id", 890l), // Expression.eq("latitude", -1d))); List<School> list = getHibernateTemplate().findByCriteria(crit, start, max); return list; } public List<ProcessType> getDefaultProcessTypes() { DetachedCriteria crit = DetachedCriteria.forClass(ProcessType.class) .add(Expression.eq("useByDefault", true)).addOrder(Order.asc("id")); return getHibernateTemplate().findByCriteria(crit); } public List<RatingType> getDefaultRatingTypes() { DetachedCriteria crit = DetachedCriteria.forClass(RatingType.class).add(Expression.eq("useByDefault", true)) .addOrder(Order.asc("id")); return getHibernateTemplate().findByCriteria(crit); } public ProcessType getProcessForName(String string) { DetachedCriteria crit = DetachedCriteria.forClass(ProcessType.class).add(Expression.eq("name", string)); return (ProcessType) DataAccessUtils.uniqueResult(getHibernateTemplate().findByCriteria(crit)); } public School getSchoolFromName(String name) { return (School) DataAccessUtils.uniqueResult(getHibernateTemplate().find("from School where name=?", name)); } public List<School> getSchoolsMatching(String match) { return getSchoolsMatching(match, 0, autoCompleteMax, MatchMode.ANYWHERE); } /** * use start matchmode */ public List<School> getSchoolsMatching(String match, int start, int max) { return getSchoolsMatching(match, start, max, MatchMode.START); } public List<School> getSchoolsMatching(String match, int start, int max, MatchMode matchMode) { DetachedCriteria crit = DetachedCriteria.forClass(School.class) .add(Expression.ilike("name", match, matchMode)).addOrder(Order.asc("name")); List<School> list = getHibernateTemplate().findByCriteria(crit, start, max); return list; } public List<ProcessType> matchProcessType(String queryString) { DetachedCriteria crit = DetachedCriteria.forClass(ProcessType.class) .add(Expression.ilike("name", queryString, MatchMode.ANYWHERE)).addOrder(Order.asc("name")); List<ProcessType> list = getHibernateTemplate().findByCriteria(crit, 0, autoCompleteMax); return list; } public Loadable save(Loadable loadable) { getHibernateTemplate().saveOrUpdate(loadable); return loadable; } public void delete(Loadable loadable) { getHibernateTemplate().delete(loadable); getHibernateTemplate().flush(); } /** * Change the number of autocomplete matches that are returned. * * @param autoCompleteMax */ public void setAutoCompleteMax(int autoCompleteMax) { this.autoCompleteMax = autoCompleteMax; } public int getAutoCompleteMax() { return autoCompleteMax; } /** * get the total number of rows without actually returning all rows * NOTE: important to set the start row here, otherwise when we start * paging, this criteria will be affected and we won't get the first * row. * * @param criteria * @return */ private int getRowCount(DetachedCriteria criteria) { criteria.setProjection(Projections.rowCount()); return ((Integer) getHibernateTemplate().findByCriteria(criteria, 0, 1).get(0)).intValue(); } /** * * Posts that are threads will have their threadPost field == null. * * Could try to optimize by getting close to: SELECT f.id, * f.thread_id, count(s.id) FROM `forumposts` f left JOIN forumposts s * on f.id = s.thread_id WHERE f.thread_id IS NULL group by f.id * * @param topicName * */ public PostsList getThreads(Class<? extends ForumPost> forumClass, String topicName, long topicID, int start, int max) { System.out.println("start " + start + " max " + max); DetachedCriteria crit = DetachedCriteria.forClass(forumClass, "fp") .add(Expression.and(Expression.eq(topicName, topicID), Expression.isNull("threadPost"))) .addOrder(Order.desc("date")); // alternative // String query = "select post, count(rp) from " + forumClass // + " post left join post.replies as rp where post." // + topicName // + " = ? and post.threadPost is null group by post." // + topicName + " order by post.date desc "; // List<Object[]> res = finder(query, topicID); // List<ForumPost> posts = new ArrayList<ForumPost>(res.size()); // for (Object[] objects : res) { // ForumPost fp = (ForumPost) objects[0]; // long count = (Long) objects[1]; // fp.setReplyCount((int) count); // posts.add(fp); // } List<ForumPost> posts = getHibernateTemplate().findByCriteria(crit, start, max); // set the reply count so we can have this information w/o // loading // the actual set. for (ForumPost fp : posts) { fp.setReplyCount(fp.getReplies().size()); } PostsList rtn = new PostsList(posts, getRowCount(crit)); return rtn; } private List finder(String hql, Object... args) { return getHibernateTemplate().find(hql, args); } public PostsList getPostsForThread(ForumPost post, int start, int max) { DetachedCriteria crit = DetachedCriteria.forClass(ForumPost.class) .add(Expression.or(Expression.eq("threadPost.id", post.getId()), Expression.eq("id", post.getId()))) .addOrder(Order.asc("date")); List<ForumPost> posts = getHibernateTemplate().findByCriteria(crit, start, max); PostsList rtn = new PostsList(posts, getRowCount(crit)); return rtn; } public PostsList getSchoolThreads(long schoolID, int start, int max) { return getThreads(SchoolForumPost.class, "school.id", schoolID, start, max); } public PostsList getUserThreads(long userID, int start, int max) { return getThreads(UserForumPost.class, "user.id", userID, start, max); } public PostsList getRecentForumPosts(int start, int max) { DetachedCriteria crit = DetachedCriteria.forClass(ForumPost.class, "fp") .add(Expression.isNull("threadPost")).addOrder(Order.desc("date")); List<ForumPost> posts = getHibernateTemplate().findByCriteria(crit, start, max); PostsList rtn = new PostsList(posts, getRowCount(crit)); return rtn; } /** * Batch Update in HQL * http://www.hibernate.org/hib_docs/reference/en/html/batch.html#batch-direct */ public void incrementSchoolPopularity(final School school) { getHibernateTemplate().execute(new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException, SQLException { String hql = "update School set popularityCounter = popularityCounter + 1 where id = :id"; int updated = session.createQuery(hql).setLong("id", school.getId()).executeUpdate(); return updated; } }); } public List<User> getUsersInterestedIn(School school) { return getUsersInterestedIn(school, 10); } public List<User> getUsersInterestedIn(School school, int max) { DetachedCriteria crit = DetachedCriteria.forClass(Application.class, "app") .add(Expression.eq("school", school)); List<Application> applications = getHibernateTemplate().findByCriteria(crit, 0, max); List<User> users = new ArrayList<User>(applications.size()); for (Application app : applications) { users.add(app.getUser()); } return users; } }