package us.codecraft.webmagic;
   
   import java.util.concurrent.TimeUnit;
   import java.util.concurrent.locks.Condition;
   import java.util.concurrent.locks.ReentrantLock;
   
   import us.codecraft.webmagic.scheduler.Scheduler;
   import us.codecraft.webmagic.thread.CountableThreadPool;
   
  public class SpiderScheduler {
      private Scheduler scheduler;
      private final ReentrantLock newUrlLock = new ReentrantLock();
      private final Condition newUrlCondition = newUrlLock.newCondition();
  
      public SpiderScheduler(Scheduler scheduler) {
          this.scheduler = scheduler;
      }
  
      public Scheduler getScheduler() {
          return scheduler;
      }
  
      public void setScheduler(Scheduler scheduler) {
          this.scheduler = scheduler;
      }
  
      public Request poll(Spider spider) {
          return scheduler.poll(spider);
      }
  
      public void push(Request request, Spider spider) {
          scheduler.push(request, spider);
      }
  
      public boolean waitNewUrl(CountableThreadPool threadPool, long emptySleepTime) {
          newUrlLock.lock();
          try {
              if (threadPool.getThreadAlive() == 0) {
                  return false;
              }
              newUrlCondition.await(emptySleepTime, TimeUnit.MILLISECONDS);
              return false;
          } catch (InterruptedException e) {
              return true;
          } finally {
              newUrlLock.unlock();
          }
      }
  
      public void signalNewUrl() {
          try {
              newUrlLock.lock();
              newUrlCondition.signalAll();
          } finally {
              newUrlLock.unlock();
          }
      }
  
  }