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
19 package org.apache.hadoop.hbase.codec.prefixtree.encode.tokenize;
20
21 import java.util.Comparator;
22
23 import org.apache.hadoop.hbase.classification.InterfaceAudience;
24
25 /**
26 * Determines order of nodes in the output array. Maybe possible to optimize further.
27 */
28 @InterfaceAudience.Private
29 public class TokenDepthComparator implements Comparator<TokenizerNode> {
30
31 @Override
32 public int compare(TokenizerNode a, TokenizerNode b) {
33 if(a==null){
34 throw new IllegalArgumentException("a cannot be null");
35 }
36 if(b==null){
37 throw new IllegalArgumentException("b cannot be null");
38 }
39
40 // put leaves at the end
41 if (!a.isLeaf() && b.isLeaf()) {
42 return -1;
43 }
44 if (a.isLeaf() && !b.isLeaf()) {
45 return 1;
46 }
47
48 if (a.isLeaf() && b.isLeaf()) {// keep leaves in sorted order (for debugability)
49 return a.getId() < b.getId() ? -1 : 1;
50 }
51
52 // compare depth
53 if (a.getTokenOffset() < b.getTokenOffset()) {
54 return -1;
55 }
56 if (a.getTokenOffset() > b.getTokenOffset()) {
57 return 1;
58 }
59
60 // if same depth, return lower id first. ids are unique
61 return a.getId() < b.getId() ? -1 : 1;
62 }
63
64 }