1 /**
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.hadoop.hbase.master.balancer;
19
20 import java.util.Comparator;
21
22 import org.apache.hadoop.hbase.HRegionInfo;
23
24 /**
25 * The following comparator assumes that RegionId from HRegionInfo can represent
26 * the age of the region - larger RegionId means the region is younger. This
27 * comparator is used in balanceCluster() to account for the out-of-band regions
28 * which were assigned to the server after some other region server crashed.
29 */
30 class RegionInfoComparator implements Comparator<HRegionInfo> {
31 @Override
32 public int compare(HRegionInfo l, HRegionInfo r) {
33 long diff = r.getRegionId() - l.getRegionId();
34 if (diff < 0) return -1;
35 if (diff > 0) return 1;
36 return 0;
37 }
38 }