/*
    * 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.master;
  
  import java.io.Serializable;
  import java.util.Comparator;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.ServerName;
  
  /**
   * Stores the plan for the move of an individual region.
   *
   * Contains info for the region being moved, info for the server the region
   * should be moved from, and info for the server the region should be moved
   * to.
   *
   * The comparable implementation of this class compares only the region
   * information and not the source/dest server info.
   */
  @InterfaceAudience.LimitedPrivate("Coprocessors")
  @InterfaceStability.Evolving
  public class RegionPlan implements Comparable<RegionPlan> {
    private final HRegionInfo hri;
    private final ServerName source;
    private ServerName dest;
  
    public static class RegionPlanComparator implements Comparator<RegionPlan>, Serializable {
      private static final long serialVersionUID = 4213207330485734853L;
  
      @Override
      public int compare(RegionPlan l, RegionPlan r) {
        return RegionPlan.compareTo(l, r);
      }
    }
  
    /**
     * Instantiate a plan for a region move, moving the specified region from
     * the specified source server to the specified destination server.
     *
     * Destination server can be instantiated as null and later set
     * with {@link #setDestination(ServerName)}.
     *
     * @param hri region to be moved
     * @param source regionserver region should be moved from
     * @param dest regionserver region should be moved to
     */
    public RegionPlan(final HRegionInfo hri, ServerName source, ServerName dest) {
      this.hri = hri;
      this.source = source;
      this.dest = dest;
    }
  
    /**
     * Set the destination server for the plan for this region.
     */
    public void setDestination(ServerName dest) {
      this.dest = dest;
    }
  
    /**
     * Get the source server for the plan for this region.
     * @return server info for source
     */
    public ServerName getSource() {
      return source;
    }
  
    /**
     * Get the destination server for the plan for this region.
     * @return server info for destination
     */
    public ServerName getDestination() {
      return dest;
    }
  
    /**
     * Get the encoded region name for the region this plan is for.
     * @return Encoded region name
     */
    public String getRegionName() {
      return this.hri.getEncodedName();
   }
 
   public HRegionInfo getRegionInfo() {
     return this.hri;
   }
 
   /**
    * Compare the region info.
    * @param other region plan you are comparing against
    */
   @Override
   public int compareTo(RegionPlan other) {
     return compareTo(this, other);
   }
 
   private static int compareTo(RegionPlan left, RegionPlan right) {
     int result = compareServerName(left.source, right.source);
     if (result != 0) {
       return result;
     }
     if (left.hri == null) {
       if (right.hri != null) {
         return -1;
       }
     } else if (right.hri == null) {
       return +1;
     } else {
       result = left.hri.compareTo(right.hri);
     }
     if (result != 0) {
       return result;
     }
     return compareServerName(left.dest, right.dest);
   }
 
   private static int compareServerName(ServerName left, ServerName right) {
     if (left == null) {
       return right == null? 0: -1;
     } else if (right == null) {
       return +1;
     }
     return left.compareTo(right);
   }
 
   @Override
   public int hashCode() {
     final int prime = 31;
     int result = 1;
     result = prime * result + ((dest == null) ? 0 : dest.hashCode());
     result = prime * result + ((hri == null) ? 0 : hri.hashCode());
     result = prime * result + ((source == null) ? 0 : source.hashCode());
     return result;
   }
 
   @Override
   public boolean equals(Object obj) {
     if (this == obj) {
       return true;
     }
     if (obj == null) {
       return false;
     }
     if (getClass() != obj.getClass()) {
       return false;
     }
     RegionPlan other = (RegionPlan) obj;
     if (dest == null) {
       if (other.dest != null) {
         return false;
       }
     } else if (!dest.equals(other.dest)) {
       return false;
     }
     if (hri == null) {
       if (other.hri != null) {
         return false;
       }
     } else if (!hri.equals(other.hri)) {
       return false;
     }
     if (source == null) {
       if (other.source != null) {
         return false;
       }
     } else if (!source.equals(other.source)) {
       return false;
     }
     return true;
   }
 
   @Override
   public String toString() {
     return "hri=" + this.hri.getRegionNameAsString() + ", src=" +
       (this.source == null? "": this.source.toString()) +
       ", dest=" + (this.dest == null? "": this.dest.toString());
   }
 }