scheduler.java

SAP这个系统的一个转换器

package com.idoc.timer;

/**
 * <p>Title: IDOC Interface</p>
 * <p>Description: IDOC 转换器</p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>Company: SiChuan XinHua</p>
 * @author Richary
 * @version 1.0
 */

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

public class Scheduler {

  class SchedulerTimerTask extends TimerTask {
      private SchedulerTask schedulerTask;
      private ScheduleIterator iterator;
      private String type = "";
      public SchedulerTimerTask(SchedulerTask schedulerTask,
              ScheduleIterator iterator,String type) {
          this.schedulerTask = schedulerTask;
          this.iterator = iterator;
          this.type = type;
      }
      public void run() {
          schedulerTask.run();
          reschedule(schedulerTask, iterator,type);
      }
  }

  private final Timer timer = new Timer();

  public Scheduler() {
  }


  /**
   * Terminates this <code>Scheduler</code>, discarding any currently scheduled tasks. Does not interfere with a currently executing task (if it exists). Once a scheduler has been terminated, its execution thread terminates gracefully, and no more tasks may be scheduled on it.
   * <p>
   * Note that calling this method from within the run method of a scheduler task that was invoked by this scheduler absolutely guarantees that the ongoing task execution is the last task execution that will ever be performed by this scheduler.
   * <p>
   * This method may be called repeatedly; the second and subsequent calls have no effect.
   */

  public void cancel() {
          timer.cancel();
      }

  /**
   * Schedules the specified task for execution according to the specified schedule. If times specified by the <code>ScheduleIterator</code> are in the past they are scheduled for immediate execution.
   * <p>
   * @param schedulerTask task to be scheduled
   * @param iterator iterator that describes the schedule
   * @throws IllegalStateException if task was already scheduled or cancelled, scheduler was cancelled, or scheduler thread terminated.
   */

      public void schedule(SchedulerTask schedulerTask,
              ScheduleIterator iterator,String type) {

          Date time = iterator.next(type);
          if (time == null) {
              schedulerTask.cancel();
          } else {
              synchronized(schedulerTask.lock) {
                  if (schedulerTask.state != SchedulerTask.VIRGIN) {
                      throw new IllegalStateException("Task already scheduled " +
                          "or cancelled");
                  }
                  schedulerTask.state = SchedulerTask.SCHEDULED;
                  schedulerTask.timerTask =
                      new SchedulerTimerTask(schedulerTask, iterator,type);
                  timer.schedule(schedulerTask.timerTask, time);
                  //timer.scheduleAtFixedRate(schedulerTask.timerTask,time,15000);
              }
          }
      }

      private void reschedule(SchedulerTask schedulerTask,
              ScheduleIterator iterator,String type) {

          Date time = iterator.next(type);
          if (time == null) {
              schedulerTask.cancel();
          } else {
              synchronized(schedulerTask.lock) {
                  if (schedulerTask.state != SchedulerTask.CANCELLED) {
                      schedulerTask.timerTask =
                          new SchedulerTimerTask(schedulerTask, iterator,type);
                      timer.schedule(schedulerTask.timerTask, time);
                      //timer.scheduleAtFixedRate(schedulerTask.timerTask,time,15000);
                  }
              }
          }
      }

}