timefinder.java

来自「100多M的J2EE培训内容」· Java 代码 · 共 118 行

package com.borland.training.meetings.sessions;

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

public class TimeFinder {

  private static TimeFinder instance = null;
  private EJBHomeFactory homeFactory;

  private TimeFinder() throws NamingException {
    homeFactory = EJBHomeFactory.getInstance();
  }

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

  public TimePeriod firstAvailableTime(Collection attendees, java.util.Date earliestTime)
    throws FinderException, NamingException {

    Collection meetings = null;
    int defaultInterval = 1;
    long maxAttempts = 10;
    int attempt = 0; // number of times the earliestTime was shifted to later
    TimePeriod result = new TimePeriod();

    MeetingHome meetingHome = (MeetingHome) homeFactory.lookupByLocalEJBReference("Meeting");

    boolean conflictFound = true;
    System.out.println("Entering the main loop");

    earliestSearch:
    while(attempt++ < maxAttempts && conflictFound) {
      conflictFound = false;
      System.out.println("Looking for meetings in progress at: " + earliestTime);
      // find all meetings that will be in progress at earliestTime
      meetings = meetingHome.findByTime(
        new java.sql.Timestamp(earliestTime.getTime()),
        new java.sql.Timestamp(earliestTime.getTime()));
      // for each meeting
      Iterator miter = meetings.iterator();
      while(miter.hasNext()) {
        Meeting meeting = (Meeting) miter.next();
        // for each attendee within each meeting
        System.out.println("Checking meeting: " + meeting.getId() +
          ", " + meeting.getTopic() + ", " + meeting.getStartTime() +
          ", " + meeting.getFinishTime());
        Iterator aiter = meeting.getAttendees().iterator();
        while(aiter.hasNext()) {
          Attendee attendee = (Attendee) aiter.next();
          System.out.println("\tChecking attendee: " + attendee.getName());
          // if meeting is scheduled for one of the specified attendees
          if(attendees.contains(attendee)) {
            System.out.println("\tConflict discovered for attendee: " + attendee.getName());
            // select a new earliest time (= when this meeting finishes)
            earliestTime = meeting.getFinishTime();
            conflictFound = true;
            continue earliestSearch;
          }
        }
      }
    }

    if(conflictFound) {
      System.out.println("No available time period");
      // No available time period
      return null;
    }

    // earliestTime found
    result.setStartTime(earliestTime);
    Calendar cal = Calendar.getInstance();
    cal.setTime(earliestTime);
    cal.add(Calendar.HOUR, defaultInterval);
    result.setFinishTime(cal.getTime());

    System.out.println("Proposed time period: " + result.getStartTime() + ", " + result.getFinishTime());
    // now search for timeInterval
    System.out.println("Checking if endTime conflicts with any meetings");
    meetings = meetingHome.findByTime(
      new java.sql.Timestamp(result.getStartTime().getTime()),
      new java.sql.Timestamp(result.getFinishTime().getTime()));
    Iterator miter = meetings.iterator();
    // find earliest starting time amongst pertinent meetings
    while(miter.hasNext()) {
      Meeting meeting = (Meeting)
        javax.rmi.PortableRemoteObject.narrow(miter.next(), Meeting.class);
      System.out.println("Checking meeting: " + meeting.getId() +
        ", " + meeting.getTopic() + ", " + meeting.getStartTime() +
        ", " + meeting.getFinishTime());
      Iterator aiter = meeting.getAttendees().iterator();
      while(aiter.hasNext()) {
        Attendee attendee = (Attendee) aiter.next();
        // if meeting is scheduled to include one of the attendees
        System.out.println("\tChecking attendee: " + attendee.getName());
        if (attendees.contains(attendee)) {
          System.out.println("\tAttendee in the list");
          java.util.Date startTime = meeting.getStartTime();
          Calendar calStart = Calendar.getInstance();
          calStart.setTime(startTime);
          Calendar calEnd = Calendar.getInstance();
          calEnd.setTime(result.getFinishTime());
          if(calStart.before(calEnd)) {
            result.setFinishTime(startTime);
          }
          System.out.println("\tSetting endTime to: " + result.getFinishTime());
        }
      }
    }
    return result;
  }
}