package org.nutz.dao.impl.ext;
import javax.sql.DataSource;
import org.nutz.aop.AopCallback;
import org.nutz.dao.SqlManager;
import org.nutz.dao.entity.Entity;
import org.nutz.dao.entity.EntityMaker;
import org.nutz.dao.impl.EntityHolder;
import org.nutz.dao.impl.NutDao;
/**
* 支持简单的懒加载机制的NutDao<p/>
* <b>注意: 如果存在双向关联,且你打算使用基于getter/setter的序列化工具来序列化这些对象,那么必须设置cycle=false,使关联对象的字段使用普通加载,而非懒加载</b>
* @author wendal(wendal1985@gmail.com)
*
*/
public class LazyNutDao extends NutDao {
private boolean cycle = false;
public void setDataSource(DataSource ds) {
super.setDataSource(ds);
this.holder = new EntityHolder(this) {
@SuppressWarnings("unchecked")
public <T> Entity<T> getEntity(Class<T> classOfT) {
if (AopCallback.class.isAssignableFrom(classOfT))
return (Entity<T>) getEntity(classOfT.getSuperclass());
return super.getEntity(classOfT);
}
};
this.holder.maker = createEntityMaker();
}
protected EntityMaker createEntityMaker() {
if (cycle)
return new LazyAnnotationEntityMaker(dataSource, expert, holder, this);
return new LazyAnnotationEntityMaker(dataSource, expert, holder, new NutDao(dataSource));
}
public LazyNutDao() {
super();
}
public LazyNutDao(DataSource dataSource) {
super(dataSource);
}
public LazyNutDao(DataSource dataSource, boolean cycle) {
super(dataSource);
setCycle(cycle);
}
public LazyNutDao(DataSource dataSource, SqlManager sqlManager) {
super(dataSource, sqlManager);
}
public void setCycle(boolean cycle) {
if (this.cycle != cycle) {
this.cycle = cycle;
this.holder.maker = createEntityMaker();
}
}
}