content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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.csp.sentinel.slotchain;
  
  /**
   * Link all processor slots as a chain.
   *
   * @author qinan.qn
   */
  public abstract class ProcessorSlotChain extends AbstractLinkedProcessorSlot<Object> {
  
      /**
       * Add a processor to the head of this slot chain.
       *
       * @param protocolProcessor processor to be added.
       */
      public abstract void addFirst(AbstractLinkedProcessorSlot<?> protocolProcessor);
  
      /**
       * Add a processor to the tail of this slot chain.
       *
       * @param protocolProcessor processor to be added.
       */
      public abstract void addLast(AbstractLinkedProcessorSlot<?> protocolProcessor);
  }
  