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.aliyun.odps.io;
  
  /**
   * WritableComparable 接口同时继承了 {@link Writable} 和 {@link Comparable}.
   *
   * <p>
   * <code>WritableComparable</code>s 对象之间可以进行比较，{@link Mapper} 输出的 Key
   * 都需要实现此接口用于排序.
   * </p>
   *
   * <p>
   * 代码示例:
   *
   * <pre>
   * public class MyWritableComparable implements WritableComparable {
   *   // Some data
   *   private int counter;
   *   private long timestamp;
   *
   *   public void write(DataOutput out) throws IOException {
   *     out.writeInt(counter);
   *     out.writeLong(timestamp);
   *   }
   *
   *   public void readFields(DataInput in) throws IOException {
   *     counter = in.readInt();
   *     timestamp = in.readLong();
   *   }
   *
   *   public int compareTo(MyWritableComparable w) {
   *     int thisValue = this.value;
   *     int thatValue = ((IntWritable) o).value;
   *     return (thisValue &lt; thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
   *   }
   * }
   * </pre>
   *
   * </p>
   */
  public interface WritableComparable<T> extends Writable, Comparable<T> {
  
  }
  