groupmanagerbean.java

老外的在线考试

/*
 * UserEJB - CyberDemia's User management library implemented using EJBs.
 * Copyright (C) 2004 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.user;
import javax.ejb.*;
import javax.naming.*;
import java.util.*;
//import java.util.logging.*;
import com.cyberdemia.ejb.BaseSessionBean;

/**
 * GroupManagerBean is a facade that provides
 * useful methods for managing user groups.
 *
 * @ejb.bean name="GroupManagerBean"
 *           type="Stateless"
 *           view-type="remote"
 *           jndi-name="ejb/GroupManager"
 *
 * @ejb.util generate="physical"
 * @ejb.interface remote-class="com.cyberdemia.user.GroupManager" extends="javax.ejb.EJBObject"
 * @ejb.home remote-class="com.cyberdemia.user.GroupManagerHome" extends="javax.ejb.EJBHome"
 * @ejb.ejb-ref ejb-name="UserBean" ref-name="ejb/LocalUser" view-type="local"
 * @ejb.ejb-ref ejb-name="GroupBean" ref-name="ejb/LocalGroup" view-type="local"
 *
 * @author Alexander Yap
 * @version $Revision: 1.4 $ at $Date: 2004/06/05 14:55:23 $ by $Author: alexycyap $
 *
 */
public class GroupManagerBean extends BaseSessionBean
{

	/**
	 * Adds a new group to the database using the data passed in
	 * by a GroupData instance. Some fields in GroupData are ignored, such
	 * as id and createdMillis.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param data GroupData instance storing data for the new group.
	 * @param userIdCollection IDs of existing users to add to this new group, or null to not add any user.
	 * @return Unique ID (primary key) of the new group.
	 * @throws UserException if an error occurs.
	 */
	public Integer addGroup(GroupData data, Collection userIdCollection) throws UserException
	{
		Integer gid = null;
		try
		{
			LocalGroup group = s_groupHome.create(data.getName(), data.getParentId());
			if (userIdCollection!=null)
			{
				Collection usersInGroupCollection = group.getUsers();
				Iterator userIdIter = userIdCollection.iterator();
				while (userIdIter.hasNext())
				{
					LocalUser user = UserManagerBean.doFindUserById((Integer)userIdIter.next());
					usersInGroupCollection.add(user);
				}
			}
			gid = group.getGeneratedPrimaryKey();
		}
		catch (CreateException ex)
		{
			getSessionContext().setRollbackOnly();
			throw new UserException("Error adding group "+data.getName(), ex);
		}

		return gid;
	}

	/**
	 * Removed an existing group from the database.
	 * Associated users are NOT removed.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param id Unique ID of group to remove.
	 * @throws UserException if there is an error.
	 */
	public void removeGroup(Integer id) throws UserException
	{
		LocalGroup group =  null;
		try
		{
			group = s_groupHome.findByPrimaryKey(id);
		}
		catch (FinderException fex)
		{
			throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+id, fex);
		}

		try
		{
			group.remove();
		}
		catch (Exception ex)
		{
			getSessionContext().setRollbackOnly();
			throw new UserException("Error removing Group with ID "+id, ex);
		}
	}

	/**
	 * Updates an existing group. Only a few fields in group may be updated.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param id ID of group to update
	 * @param name New group name
	 * @throws UserException if an error occurs such as the id is invalid.
	 */
	public void setGroup(Integer id, String name) throws UserException
	{
		LocalGroup group =  null;
		try
		{
			group = s_groupHome.findByPrimaryKey(id);
		}
		catch (FinderException fex)
		{
			throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+id, fex);
		}
		
		group.setName(name);
	}
	
	/**
	 * Gets the data of a group identified by its unique ID. 
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param id Group ID.
	 * @param includeUsers true to retrieve associated users' data, otherwisse false.
	 * @param includeUserRoles if includeUsers is true, then setting includeUserRoles to true will also retrieve the users' roles, otherwise roles are not retrieved.
	 * @return GroupData instance storing the group's data, or null if the group doesn't exist.
	 * @throws UserException if there is an error.
	 */
	public GroupData getGroupData(Integer id, boolean includeUsers, boolean includeUserRoles) throws UserException
	{
		LocalGroup group =  null;
		try
		{
			group = s_groupHome.findByPrimaryKey(id);
		}
		catch (FinderException fex)
		{
			throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+id, fex);
		}

		GroupData data = null;
		try
		{
			data = createGroupData(group, includeUsers, includeUserRoles);
		}
		catch (Exception ex)
		{
			throw new UserException( "Error getting data for Group "+group.getName(), ex);
		}
		return data;
	}

	/**
	 * Gets the data of all groups with the specified parent ID.
	 * Optionally return associated users' data.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param parentId Parent ID to search for.
	 * @param includeUsers true to retrieve associated users' data, otherwisse false.
	 * @param includeUserRoles if includeUsers is true, then setting includeUserRoles to true will also retrieve the users' roles, otherwise roles are not retrieved.
	 * @return Array of GroupData instances for found groups, or empty array if no group found.
	 */
	public GroupData[] getGroupsByParentId(String parentId, boolean includeUsers, boolean includeUserRoles)
	{
		GroupData[] groupDataArr = null;
		try
		{
			Collection groupCollection = s_groupHome.findByParentId(parentId);
			groupDataArr = convertGroupCollectionToDataArray(groupCollection, includeUsers, includeUserRoles);
		}
		catch (FinderException fex)
		{
			groupDataArr = new GroupData[0];
		}
		
		return groupDataArr;
	}
	
	/**
	 * Gets the data of all groups containing the specified user. 
	 * This method will <b>not</b> retrieve any user or role related data,
	 * since the caller of this method probably already has the details of the user
	 * in question.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param userId User ID to match.
	 * @return  Array of GroupData instances for found groups, or empty array if no group found.
	 */
	public GroupData[] getGroupsByUser(Integer userId) throws UserException
	{
		LocalUser user = UserManagerBean.doFindUserById(userId);
		Collection groupCollection = user.getGroups();
		return convertGroupCollectionToDataArray(groupCollection, false, false);
		
	}

	/**
	 * Assigns a list of users to a group.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param userIdList List of user IDs.
	 * @param groupId Group ID
	 * @throws UserException if there is an error.
	 */
	public void assignUsersToGroup(List userIdList, Integer groupId) throws UserException
	{
		LocalGroup group =  null;
		try
		{
			group = s_groupHome.findByPrimaryKey(groupId);
		}
		catch (FinderException fex)
		{
			throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+groupId, fex);
		}
		
		Collection usersInGroupCollection = group.getUsers();

		Iterator userIdIter = userIdList.iterator();
		while (userIdIter.hasNext())
		{
			Integer userId = (Integer)userIdIter.next();
			try
			{
				LocalUser user = UserManagerBean.doFindUserById(userId);
				usersInGroupCollection.add(user);
			}
			catch (UserException uex)
			{
				getSessionContext().setRollbackOnly();
				throw uex;
			}
		}
	}
	
	/**
	 * Assigns a user to a list of groups.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param userId User Id
	 * @param groupIdList List of group IDs to assign user to.
	 * @throws UserException if there is an error.
	 */
	public void assignUserToGroups(Integer userId, List groupIdList) throws UserException
	{
		LocalUser user = UserManagerBean.doFindUserById(userId);
		
		Iterator groupIdIter = groupIdList.iterator();
		while (groupIdIter.hasNext())
		{
			Integer groupId = (Integer)groupIdIter.next();
			LocalGroup group =  null;
			try
			{
				group = s_groupHome.findByPrimaryKey(groupId);
				Collection usersInGroupCollection = group.getUsers();
				usersInGroupCollection.add(user);
			}
			catch (FinderException fex)
			{
				getSessionContext().setRollbackOnly();
				throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+groupId, fex);
			}
			
		}
	}
	
	
	/**
	 * Removes a list of users from a group.
	 *
	 * @ejb.interface-method
	 * @ejb.transaction type="Required"
	 *
	 * @param id ID of group to remove users from.
	 * @param userIdToRemoveList List of user IDs to remove.
	 * @throws UserException if there is an error.
	 */
	public void removeUsersFromGroup(Integer id, List userIdToRemoveList) throws UserException
	{
		LocalGroup group =  null;
		try
		{
			group = s_groupHome.findByPrimaryKey(id);
		}
		catch (FinderException fex)
		{
			throw new UserException(UserException.GROUP_NOT_FOUND, "Cannot find Group with ID "+id, fex);
		}
		
		Collection usersInGroupCollection = group.getUsers();
		Iterator userToRemoveIdIter = userIdToRemoveList.iterator();
		while (userToRemoveIdIter.hasNext())
		{
			try
			{
				LocalUser user = UserManagerBean.doFindUserById((Integer)userToRemoveIdIter.next());
				usersInGroupCollection.remove(user);
			}
			catch (UserException uex)
			{
				getSessionContext().setRollbackOnly();
				throw uex;				
			}
		}
	}
	
    /**
     * Dummy create method.
     *
     * @ejb.create-method view-type="remote"
     */
    public void ejbCreate()
    {
        // Nothing here
    }


	private static GroupData createGroupData(LocalGroup group, boolean includeUsers, boolean includeUserRoles)
	{
		GroupData data = new GroupData(group.getId(), group.getParentId(), group.getName(), group.getCreatedMillis());
		if (includeUsers)
		{			
			UserData[] users = UserManagerBean.convertUserCollectionToDataArray(group.getUsers(), includeUserRoles);
			data.setUsers(users);
		}
		return data;
	}

		
	private static GroupData[] convertGroupCollectionToDataArray(Collection groupCollection, boolean includeUsers, boolean includeUserRoles)
	{
		GroupData[] groupDataArr = new GroupData[groupCollection.size()];
		Iterator groupIter = groupCollection.iterator();
		for (int gidx=0; groupIter.hasNext(); gidx++)
		{
			LocalGroup group = (LocalGroup)groupIter.next();
			groupDataArr[gidx] = createGroupData(group, includeUsers, includeUserRoles);
		}
		return groupDataArr;
	}
	
	
	
	private static LocalGroupHome s_groupHome = null;
	static
	{
		try
		{
			Context ctx = new InitialContext();
			try
			{
				s_groupHome = (LocalGroupHome)ctx.lookup(JNDI_PREFIX+LocalGroupHome.JNDI_NAME);
			}
			finally
			{
				ctx.close();
			}
		}
		catch (NamingException nex)
		{
			throw new EJBException("Error retrieving homes", nex);
		}
	}

}