/**
    * 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 java.io.IOException;
  
  import org.apache.hadoop.hbase.util.ByteStringer;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
  import org.apache.hadoop.hbase.util.Bytes;
  
  /**
   * Current state of a region in transition.  Holds state of a region as it moves through the
   * steps that take it from offline to open, etc.  Used by regionserver, master, and zk packages.
   * Encapsulates protobuf serialization/deserialization so we don't leak generated pb outside this
   * class.  Create an instance using createRegionTransition(EventType, byte[], ServerName).
   * <p>Immutable
   */
  @InterfaceAudience.Private
  public class RegionTransition {
    private final ZooKeeperProtos.RegionTransition rt;
  
    /**
     * Shutdown constructor
     */
    private RegionTransition() {
      this(null);
    }
  
    private RegionTransition(final ZooKeeperProtos.RegionTransition rt) {
      this.rt = rt;
    }
  
    public EventType getEventType() {
      return EventType.get(this.rt.getEventTypeCode());
    }
  
    public ServerName getServerName() {
      return ProtobufUtil.toServerName(this.rt.getServerName());
    }
  
    public long getCreateTime() {
      return this.rt.getCreateTime();
    }
  
    /**
     * @return Full region name
     */
    public byte [] getRegionName() {
      return this.rt.getRegionName().toByteArray();
    }
  
    public byte [] getPayload() {
      return this.rt.getPayload().toByteArray();
    }
  
    @Override
    public String toString() {
      byte [] payload = getPayload();
      return "region=" + Bytes.toStringBinary(getRegionName()) + ", state=" + getEventType() +
        ", servername=" + getServerName() + ", createTime=" + this.getCreateTime() +
        ", payload.length=" + (payload == null? 0: payload.length);
    }
  
    /**
     * @param type
     * @param regionName
     * @param sn
     * @return a serialized pb {@link RegionTransition}
     */
    public static RegionTransition createRegionTransition(final EventType type,
        final byte [] regionName, final ServerName sn) {
      return createRegionTransition(type, regionName, sn, null);
    }
  
    /**
     * @param type
     * @param regionName
     * @param sn
     * @param payload May be null
    * @return a serialized pb {@link RegionTransition}
    */
   public static RegionTransition createRegionTransition(final EventType type,
       final byte [] regionName, final ServerName sn, final byte [] payload) {
     org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ServerName pbsn =
       org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ServerName.newBuilder().
         setHostName(sn.getHostname()).setPort(sn.getPort()).setStartCode(sn.getStartcode()).build();
     ZooKeeperProtos.RegionTransition.Builder builder = ZooKeeperProtos.RegionTransition.newBuilder().
       setEventTypeCode(type.getCode()).setRegionName(ByteStringer.wrap(regionName)).
         setServerName(pbsn);
     builder.setCreateTime(System.currentTimeMillis());
     if (payload != null) builder.setPayload(ByteStringer.wrap(payload));
     return new RegionTransition(builder.build());
   }
 
   /**
    * @param data Serialized date to parse.
    * @return A RegionTransition instance made of the passed <code>data</code>
    * @throws DeserializationException 
    * @see #toByteArray()
    */
   public static RegionTransition parseFrom(final byte [] data) throws DeserializationException {
     ProtobufUtil.expectPBMagicPrefix(data);
     try {
       int prefixLen = ProtobufUtil.lengthOfPBMagic();
       ZooKeeperProtos.RegionTransition.Builder builder =
           ZooKeeperProtos.RegionTransition.newBuilder();
       ProtobufUtil.mergeFrom(builder, data, prefixLen, data.length - prefixLen);
       return new RegionTransition(builder.build());
     } catch (IOException e) {
       throw new DeserializationException(e);
     }
   }
 
   /**
    * @return This instance serialized into a byte array
    * @see #parseFrom(byte[])
    */
   public byte [] toByteArray() {
     return ProtobufUtil.prependPBMagic(this.rt.toByteArray());
   }
 }