content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.jstorm.callback;
  
  import java.util.Map;
  import java.util.Set;
  
  import org.jboss.netty.channel.Channel;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import backtype.storm.utils.DisruptorQueue;
  
  import com.alibaba.jstorm.message.netty.NettyServerFlowCtrlHandler;
  
  public class BackpressureCallback implements Callback {
      private static final Logger LOG = LoggerFactory.getLogger(BackpressureCallback.class);
  
      private NettyServerFlowCtrlHandler handler;
      private int taskId;
  
      public BackpressureCallback(NettyServerFlowCtrlHandler handler, int taskId) {
          this.taskId = taskId;
          this.handler = handler;
      }
  
      public <T> Object execute(T... args) {
          DisruptorQueue queue = (DisruptorQueue) args[0];
          if (handler.checkIfUnderFlowCtrl(queue)) {
              try {
                  handler.releaseFlowCtrl(taskId);
              } catch (InterruptedException e) {
                  LOG.warn("Failed to release flow control for task-{}", taskId);
                  return false;
              }
              return true;
          } else {
              return false;
          }
      }
  
  }
  