001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.master.balancer;
019
020import org.apache.yetus.audience.InterfaceAudience;
021
022/**
023 * An action to move or swap a region
024 */
025@InterfaceAudience.Private
026abstract class BalanceAction {
027  enum Type {
028    ASSIGN_REGION,
029    MOVE_REGION,
030    SWAP_REGIONS,
031    NULL,
032  }
033
034  static final BalanceAction NULL_ACTION = new BalanceAction(Type.NULL) {
035  };
036
037  private final Type type;
038
039  BalanceAction(Type type) {
040    this.type = type;
041  }
042
043  /**
044   * Returns an Action which would undo this action
045   */
046  BalanceAction undoAction() {
047    return this;
048  }
049
050  Type getType() {
051    return type;
052  }
053
054  @Override
055  public String toString() {
056    return type + ":";
057  }
058}