/**
* Copyright (c) http://www.hao-se.cn Ltd.,2007 All rights reserved.
*/
package com.joe.utilities.core.hibernate.entrydao.impl;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.Query;
import org.hibernate.criterion.DetachedCriteria;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import org.springframework.util.Assert;
import com.joe.utilities.core.data.PageRequest;
import com.joe.utilities.core.data.PageResponse;
import com.joe.utilities.core.hibernate.entrydao.GenericDAO;
/**
* 泛型DAO父类
*
*
* DAO异常处理原则: DAO 方法应该抛出有意义的异常。 DAO 方法不应该抛出 java.lang.Exception。<br>
* java.lang.Exception 太一般化了。它不传递关于底层问题的任何信息。 DAO 方法不应该抛出 java.sql.SQLException 。<br>
* SQLException 是一个低级别的 JDBC 异常。 一个 DAO 应该力争封装 JDBC 而不是将 JDBC公开给应用程序的其余部分。<br>
* 只有在可以合理地预期调用者可以处理异常时，DAO 接口中的方法才应该抛出检查过的异常。<br>
* 如果调用者不能以有意义的方式处理这个异常，那么考虑抛出一个未检查的(运行时)异常。 <br>
* 如果数据访问代码捕获了一个异常，不要忽略它。 忽略捕获的异常的DAO是很难进行故障诊断的。 <br>
* 使用链接的异常将低级别的异常转化为高级别的异常。 考虑定义标准DAO异常类。 <br>
* Spring Framework提供了很好的一套预定义的 DAO 异常类
*
* @author hao-se.cn（好·色）
*/
@SuppressWarnings("unchecked")
public class BaseGenericDAO<T> extends HibernateDaoSupport implements
GenericDAO<T> {
/** 日志 */
protected final Log log = LogFactory.getLog(getClass());
/** 型别 */
protected Class<T> type;
/**
* 提供给spring初始化的构造函数
*/
public BaseGenericDAO() {
super();
}
/**
* 用于初始化对应model的构造函数
*
* @param type
*/
public BaseGenericDAO(Class<T> type) {
super();
this.type = type;
}
protected String getDefalutOrderFileds() {
return null;
}
/*
* @see cn.haose.dao.GenericDAO#saveEntity(java.lang.Object)
*/
public void saveEntity(T o) {
getHibernateTemplate().saveOrUpdate(o);
}
/*
* @see cn.haose.dao.GenericDAO#deleteEntity(java.lang.Object)
*/
public void deleteEntity(T o) {
getHibernateTemplate().delete(o);
}
/*
* @see cn.haose.dao.GenericDAO#getByID(java.lang.String)
*/
public T getByID(String id) {
Object o = this.getHibernateTemplate().get(type, id);
if (o == null) {
throw new ObjectRetrievalFailureException(type, id);
}
return (T) o;
}
/*
* @see cn.haose.dao.GenericDAO#getByID(java.lang.String)
*/
public T getByID(Long id) {
Object o = this.getHibernateTemplate().get(type, id);
if (o == null) {
throw new ObjectRetrievalFailureException(type, id);
}
return (T) o;
}
/*
* @see cn.haose.dao.GenericDAO#findByDetachedCriteria(org.hibernate.criterion.DetachedCriteria)
*/
public List findByDetachedCriteria(final DetachedCriteria dc) {
return getHibernateTemplate().findByCriteria(dc);
}
public List<T> findByProperty(String propertyName, Object value) {
if (value != null) {
String queryString = "from " + getClass().getName()
+ " as model where model." + propertyName + "= ?";
return getHibernateTemplate().find(queryString, value);
} else {
String queryString = "from " + getClass().getName()
+ " as model where model." + propertyName + " is null";
return getHibernateTemplate().find(queryString);
}
}
public PageResponse<T> findByProperty1(String propertyName, Object value,
PageRequest pageRequest) {
PageResponse<T> pageResponse = new PageResponse<T>();
if (value != null) {
String queryString = "from " + getClass().getName()
+ " as model where model." + propertyName + "= :value";
Query query = getSession().createQuery(queryString);
query.setEntity("value", value);
// 取总数
Long totalCount = getHQLReulstCount(queryString);
pageResponse.setTotalCount(totalCount);
query.setFirstResult(pageRequest.getStart());
query.setMaxResults(pageRequest.getLimit());
pageResponse.setList(query.list());
pageResponse.setStart(pageRequest.getStart() + 1);
pageResponse.setEnd(pageResponse.getStart()+pageResponse.getList().size() - 1);
return pageResponse;
} else {
String queryString = "from " + getClass().getName()
+ " as model where model." + propertyName + " is null";
Query query = getSession().createQuery(queryString);
// 取总数
Long count = getHQLReulstCount(queryString.toString());
pageResponse.setTotalCount(count);
query.setFirstResult(pageRequest.getStart());
query.setMaxResults(pageRequest.getLimit());
pageResponse.setList(query.list());
pageResponse.setStart(pageRequest.getStart() + 1);
pageResponse.setEnd(pageResponse.getStart()+pageResponse.getList().size() - 1);
return pageResponse;
}
}
public PageResponse<T> findAll(PageRequest pageRequest) {
PageResponse<T> pageResponse = new PageResponse<T>();
StringBuffer hql = new StringBuffer();
hql.append(" FROM ").append(getClass().getSimpleName());
String defalutOrderFileds = getDefalutOrderFileds();
if (StringUtils.isNotEmpty(defalutOrderFileds)) {
hql.append(" order by " + defalutOrderFileds);
}
String queryString = hql.toString();
Query query = getSession().createQuery(queryString);
// 取总数
Long count = getHQLReulstCount(hql.toString());
pageResponse.setTotalCount(count);
// 取结果
query.setFirstResult(pageRequest.getStart());
query.setMaxResults(pageRequest.getLimit());
pageResponse.setList(query.list());
pageResponse.setStart(pageRequest.getStart() + 1);
pageResponse.setEnd(pageResponse.getStart()+pageResponse.getList().size() - 1);
return pageResponse;
}
public List<T> findAll() {
StringBuffer hql = new StringBuffer();
hql.append(" FROM ").append(getClass().getName());
String defalutOrderFileds = getDefalutOrderFileds();
if (StringUtils.isNotEmpty(defalutOrderFileds)) {
hql.append(" order by " + defalutOrderFileds);
}
String queryString = hql.toString();
return getHibernateTemplate().find(queryString);
}
/**
* 返回给定HQL语句的记录总条数
*
* @param hql
* @return
*/
protected Long getHQLReulstCount(String hql) {
String countSql = removeSelect(hql);
countSql = removeOrders(countSql);
countSql = removeFetchKeyword(countSql);
countSql = " select count(*) " + countSql;
Query query = getSession().createQuery(countSql);
Long count = (Long) query.uniqueResult();
return count;
}
/**
* 返回给定SQL语句的记录总条数
*
* @param hql
* @return
*/
protected Long getSQLReulstCount(String hql) {
String countSql = removeSelect(hql);
countSql = removeOrders(countSql);
countSql = removeFetchKeyword(countSql);
countSql = " select count(*) " + countSql;
Query query = getSession().createSQLQuery(countSql);
Long count = (Long) query.uniqueResult();
return count;
}
/**
* 去除select 子句，未考虑union的情况
*
* @param hql
* @return
*/
private static String removeSelect(String hql) {
Assert.hasText(hql);
int beginPos = hql.toLowerCase().indexOf("from");
Assert.isTrue(beginPos != -1, " hql : " + hql
+ " must has a keyword 'from'");
return hql.substring(beginPos);
}
/**
* 去除orderby 子句
*
* @param hql
* @return
*/
private static String removeOrders(String hql) {
Assert.hasText(hql);
Pattern p = Pattern.compile("order\\s*by[\\w|\\W|\\s|\\S]*",
Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(hql);
StringBuffer sb = new StringBuffer();
while (m.find()) {
m.appendReplacement(sb, "");
}
m.appendTail(sb);
return sb.toString();
}
private static String removeFetchKeyword(String hql) {
return hql.replaceAll("(?i)fetch", "");
}
}