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.hdfs.trident.format;
  
  import org.apache.hadoop.io.Writable;
  import storm.trident.tuple.TridentTuple;
  
  import java.io.Serializable;
  
  /**
   * Interface for converting <code>TridentTuple</code> objects to HDFS sequence file key-value pairs.
   *
   */
  public interface SequenceFormat extends Serializable {
      /**
       * Key class used by implementation (e.g. IntWritable.class, etc.)
       *
       * @return
       */
      Class keyClass();
  
      /**
       * Value class used by implementation (e.g. Text.class, etc.)
       * @return
       */
      Class valueClass();
  
      /**
       * Given a tuple, return the key that should be written to the sequence file.
       *
       * @param tuple
       * @return
       */
      Writable key(TridentTuple tuple);
  
      /**
       * Given a tuple, return the value that should be written to the sequence file.
       * @param tuple
       * @return
       */
      Writable value(TridentTuple tuple);
  }
  