package com.atlassian.core.task;
   
   import org.apache.log4j.Logger;
   
   import java.sql.Timestamp;
   import java.util.Collection;
   
   public abstract class AbstractTaskQueue implements TaskQueue
   {
      private static final transient Logger log = Logger.getLogger(AbstractTaskQueue.class);
      protected FifoBuffer<Task> buffer;
  
      private boolean flushing;
      private Timestamp flushStarted;
  
  
      public AbstractTaskQueue(FifoBuffer<Task> buffer)
      {
          this.buffer = buffer;
      }
  
      public void flush()
      {
          if (flushing)
              return;
  
          flushing = true;
          flushStarted = new Timestamp(System.currentTimeMillis());
  
          try
          {
              Task task;
              while ((task = buffer.remove()) != null)
              {
                  log.debug("Executing: " + task);
                  try
                  {
                      task.execute();
                  }
                  catch (Exception e)
                  {
                      handleException(task, e);
                  }
              }
          }
          finally
          {
              flushing = false;
              flushStarted = null;
          }
      }
  
      protected void handleException(Task task, Exception e)
      {
          log.error("Failed to execute task : " + task, e);
      }
  
      public int size()
      {
          return buffer.size();
      }
  
      public void addTask(Task task)
      {
          log.debug("Queued: " + task);
          buffer.add(task);
      }
  
      /**
       * @deprecated use getTasks() instead.
       */
      public Collection<Task> getQueue()
      {
          return buffer.getItems();
      }
  
      public boolean isFlushing()
      {
          return flushing;
      }
  
      public Timestamp getFlushStarted()
      {
          return flushStarted;
      }
  
      public void clear()
      {
          buffer.clear();
      }
  
      public Collection<Task> getTasks()
      {
          return buffer.getItems();
      }
  }