dao.java

《JSP网站开发典型模块与实例精讲》一书光盘源码

package org.appfuse.dao;

import java.io.Serializable;
import java.util.List;

/**
 * Data Access Object (DAO) interface. This is an interface used to tag our DAO
 * classes and to provide common methods to all DAOs.
 *
 * <p>
 * <a href="DAO.java.html"> <i>View Source </i> </a>
 * </p>
 *
 * @author <a href="mailto:[e-mail]">Matt Raible </a>
 */
public interface DAO {

    /**
     * Generic method used to get all objects of a particular type. This is the
     * same as lookup up all rows in a table.
     *
     * @param clazz
     *            the type of objects (a.k.a. while table) to get data from
     * @return List of populated objects
     */
    public List getObjects(Class clazz);

    /**
     * Generic method to get an object based on class and identifier. An
     * ObjectRetrievalFailureException Runtime Exception is thrown if nothing is
     * found.
     *
     * @param clazz
     *            model class to lookup
     * @param id
     *            the identifier (primary key) of the class
     * @return a populated object
     * @see org.springframework.orm.ObjectRetrievalFailureException
     */
    public Object getObject(Class clazz, Serializable id);

    /**
     * Generic method to save an object - handles both update and insert.
     *
     * @param o
     *            the object to save
     */
    public void saveObject(Object o);

    /**
     * Generic method to delete an object based on class and id
     *
     * @param clazz
     *            model class to lookup
     * @param id
     *            the identifier (primary key) of the class
     */
    public void removeObject(Class clazz, Serializable id);
}