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;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  
  /**
   * AbstractDatetimeWritable 提供了 datetime 的 {@link Writable} 和 {@link WritableComparable}
   * 的实现
   */
  public abstract class AbstractDatetimeWritable<T extends AbstractDatetimeWritable>
          implements WritableComparable<T> {
  
    protected long value;
  
    /**
     * 默认构造 datetime 值为0的 AbstractDatetimeWritable.
     */
    AbstractDatetimeWritable() {
    }
  
    /**
     * 构造时间刻度值为给定 value 的 AbstractDatetimeWritable.
     *
     * @param value 给定时间刻度，精确到毫秒
     */
    AbstractDatetimeWritable(long value) {
      set(value);
    }
  
    /**
     * 设置 AbstractDatetimeWritable 的值
     *
     * @param value 要设置的时间刻度值，精确到毫秒
     */
    public void set(long value) {
      this.value = value;
    }
  
    /**
     * 返回此 AbstractDatetimeWritable 的值
     *
     * @return 这个writable对应的时间刻度，精确到毫秒
     */
    public long get() {
      return value;
    }
  
    @Override
    public void readFields(DataInput in) throws IOException {
      value = in.readLong();
    }
  
    @Override
    public void write(DataOutput out) throws IOException {
      out.writeLong(value);
    }
  
    /**
     * 判断两个 AbstractDatetimeWritable 是否相等.
     *
     * <p>
     * 如果两个都是 AbstractDatetimeWritable 且值相等，返回true，否则返回false
     *
     * @param o
     * @return
     */
    @Override
    public boolean equals(Object o) {
      if (getClass() != o.getClass()) {
        return false;
      }
      T other = (T) o;
      return this.value == other.value;
    }
  
    /**
     * 计算哈希值，直接返回此 AbstractDatetimeWritable 的值.
     */
    @Override
    public int hashCode() {
      return (int) value;
    }
  
    /**
     * 比较两个 AbstractDatetimeWritable 的值.
     *
     * @param o
     *     比较对象
     * @return (this < o ? -1 : (this == o) ? 0 ：1))
     */
    @Override
    public int compareTo(T o) {
      return this.value < o.value ? -1 : (this.value == o.value ? 0 : 1);
    }
  
    @Override
    public String toString() {
      return Long.toString(value);
    }
  }
  