/**
    *
    * 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 org.apache.hadoop.hbase;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.util.Addressing;
  
  /**
   * Data structure to hold HRegionInfo and the address for the hosting
   * HRegionServer.  Immutable.  Comparable, but we compare the 'location' only:
   * i.e. the hostname and port, and *not* the regioninfo.  This means two
   * instances are the same if they refer to the same 'location' (the same
   * hostname and port), though they may be carrying different regions.
   *
   * On a big cluster, each client will have thousands of instances of this object, often
   *  100 000 of them if not million. It's important to keep the object size as small
   *  as possible.
   *
   * <br>This interface has been marked InterfaceAudience.Public in 0.96 and 0.98.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Evolving
  public class HRegionLocation implements Comparable<HRegionLocation> {
    private final HRegionInfo regionInfo;
    private final ServerName serverName;
    private final long seqNum;
  
    public HRegionLocation(HRegionInfo regionInfo, ServerName serverName) {
      this(regionInfo, serverName, HConstants.NO_SEQNUM);
    }
  
    public HRegionLocation(HRegionInfo regionInfo, ServerName serverName, long seqNum) {
      this.regionInfo = regionInfo;
      this.serverName = serverName;
      this.seqNum = seqNum;
    }
  
    /**
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
      return "region=" + (this.regionInfo == null ? "null" : this.regionInfo.getRegionNameAsString())
          + ", hostname=" + this.serverName + ", seqNum=" + seqNum;
    }
  
    /**
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null) {
        return false;
      }
      if (!(o instanceof HRegionLocation)) {
        return false;
      }
      return this.compareTo((HRegionLocation)o) == 0;
    }
  
    /**
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
      if (serverName == null) {
        return System.identityHashCode(this);
      }
      return this.serverName.hashCode();
    }
  
    /** @return HRegionInfo */
    public HRegionInfo getRegionInfo(){
      return regionInfo;
    }
  
    public String getHostname() {
      return this.serverName.getHostname();
    }
 
   public int getPort() {
     return this.serverName.getPort();
   }
 
   public long getSeqNum() {
     return seqNum;
   }
 
   /**
    * @return String made of hostname and port formatted as per {@link Addressing#createHostAndPortStr(String, int)}
    */
   public String getHostnamePort() {
     return Addressing.createHostAndPortStr(this.getHostname(), this.getPort());
   }
 
   public ServerName getServerName() {
     return serverName;
   }
 
   @Override
   public int compareTo(HRegionLocation o) {
     if (serverName == null) {
       if (o.serverName != null) {
         return 1;
       }
       return 0;
     } else {
       return serverName.compareTo(o.getServerName());
     }
   }
 }