meetingmanager.java

来自「100多M的J2EE培训内容」· Java 代码 · 共 122 行

package com.borland.training.meetings.sessions;

import java.util.*;
import javax.ejb.*;
import javax.naming.*;
import com.borland.training.meetings.entities.*;

class MeetingManager {

  private static MeetingManager instance = null;
  private MeetingValueFactory meetingValueFactory;
  private RoomValueFactory roomValueFactory;
  private AttendeeValueFactory attendeeValueFactory;
  private EJBHomeFactory homeFactory;

  private MeetingManager() throws NamingException {
    homeFactory = EJBHomeFactory.getInstance();
    meetingValueFactory = MeetingValueFactory.getInstance();
    attendeeValueFactory = AttendeeValueFactory.getInstance();
    roomValueFactory = RoomValueFactory.getInstance();
  }

  public static MeetingManager getInstance() throws NamingException {
    if(instance == null) {
      instance = new MeetingManager();
    }
    return instance;
  }

  public Long createMeeting(MeetingValue meetingValue)
    throws FinderException, NamingException {

    try {
      MeetingHome meetingHome =
        (MeetingHome) homeFactory.lookupByLocalEJBReference("Meeting");
      Meeting meeting = meetingHome.create(meetingValue.getTopic(),
        meetingValue.getStartTime(),
        meetingValue.getFinishTime());
      Room room = roomValueFactory.findRoom(meetingValue.getRoomName());
      meeting.setRoom(room);
      Iterator iterator = meetingValue.getAttendeeIds().iterator();
      Long id;
      Attendee attendee = null;
      Collection meetingAttendees = meeting.getAttendees();
      while(iterator.hasNext()) {
        id = (Long) iterator.next();
        attendee = attendeeValueFactory.findAttendee(id);
        meetingAttendees.add(attendee);
      }
      return meeting.getId();
    }
    catch(Exception e) {
      throw new EJBException(e);
    }
  }

  public void updateMeeting(MeetingValue meetingValue)
    throws FinderException, NamingException {

    try {
      Meeting meeting = meetingValueFactory.findMeeting(meetingValue.getId());
      meeting.setTopic(meetingValue.getTopic());
      meeting.setStartTime(meetingValue.getStartTime());
      meeting.setFinishTime(meetingValue.getFinishTime());
      if(!meeting.getRoom().getName().equals(meetingValue.getRoomName())) {
        Room newRoom = roomValueFactory.findRoom(meetingValue.getRoomName());
        meeting.setRoom(newRoom);
      }
      // Map attendee ids to references
      Long id;
      Attendee attendee = null;
      Collection attendeeIds = meetingValue.getAttendeeIds();
      Collection attendees = new Vector(attendeeIds.size());
      Iterator iterator = attendeeIds.iterator();
      while(iterator.hasNext()) {
        id = (Long) iterator.next();
        attendee = attendeeValueFactory.findAttendee(id);
        attendees.add(attendee);
      }
      // Update the attendee list.
      // Note: for large numbers of attendees, it might be more efficient to determine
      // attendees that are beeing removed or added, and remove or add them individually.
      meeting.setAttendees(attendees);
    }
    catch(Exception e) {
      throw new EJBException(e);
    }
  }

  public void removeMeeting(Long id)
    throws FinderException, NamingException {

    try {
      Meeting meeting = meetingValueFactory.findMeeting(id);
      Iterator iterator = meeting.getAttendees().iterator();
      while(iterator.hasNext()) {
        iterator.remove();
      }
      meeting.remove();
    }
    catch(Exception e) {
      throw new EJBException(e);
    }
  }

  public void removeAllMeetings()
    throws FinderException, NamingException {

    try {
      Collection meetings = meetingValueFactory.findAllMeetings();
      Iterator iterator = meetings.iterator();
      Meeting meeting = null;
      while(iterator.hasNext()) {
        meeting = (Meeting) iterator.next();
        meeting.remove();
      }
    }
    catch(Exception e) {
      throw new EJBException(e);
    }
  }
}