abstractdao.java

hibernate quickly 一书的各章节源代码

package com.manning.hq.ch08;

import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import net.sf.hibernate.Transaction;

import java.util.List;

/**
 * A layer supertype that handles the common operations for all Data Access Objects.
 */
public abstract class AbstractDao {
    private Session session;
    private Transaction tx;

    public AbstractDao() {
        HibernateFactory.buildIfNeeded();
    }

    protected Session getSession() {
        return session;
    }

    protected Transaction getTx() {
        return tx;
    }

    protected void saveOrUpdate(Object obj) {
        try {
            startOperation();
            session.saveOrUpdate(obj);
            tx.commit();
        } catch (HibernateException e) {
            handleException(e);
        } finally {
            HibernateFactory.close(session);
        }
    }

    protected void delete(Object obj) {
        try {
            startOperation();
            session.delete(obj);
            tx.commit();
        } catch (HibernateException e) {
            handleException(e);
        } finally {
            HibernateFactory.close(session);
        }
    }

    protected Object find(Class clazz, Long id) {
        Object obj = null;
        try {
            startOperation();
            obj = session.load(clazz, id);
            tx.commit();
        } catch (HibernateException e) {
            handleException(e);
        } finally {
            HibernateFactory.close(session);
        }
        return obj;
    }

    protected List findAll(Class clazz) {
        List objects = null;
        try {
            startOperation();
            objects = session.find("from " + clazz.getName());
            tx.commit();
        } catch (HibernateException e) {
            handleException(e);
        } finally {
            HibernateFactory.close(session);
        }
        return objects;
    }

    protected void handleException(HibernateException e) throws DataAcessLayerException {
        HibernateFactory.rollback(tx);
        throw new DataAcessLayerException(e);
    }

    protected void startOperation() throws HibernateException {
        session = HibernateFactory.openSession();
        tx = session.beginTransaction();
    }
}