1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.launcher3.util;
17 
18 import java.text.Collator;
19 import java.util.Comparator;
20 
21 /**
22  * Extension of {@link java.text.Collator} with special handling for digits. Used for comparing
23  * user visible labels.
24  */
25 public class LabelComparator implements Comparator<String> {
26 
27     private final Collator mCollator = Collator.getInstance();
28 
29     @Override
compare(String titleA, String titleB)30     public int compare(String titleA, String titleB) {
31         // Ensure that we de-prioritize any titles that don't start with a
32         // linguistic letter or digit
33         boolean aStartsWithLetter = (titleA.length() > 0) &&
34                 Character.isLetterOrDigit(titleA.codePointAt(0));
35         boolean bStartsWithLetter = (titleB.length() > 0) &&
36                 Character.isLetterOrDigit(titleB.codePointAt(0));
37         if (aStartsWithLetter && !bStartsWithLetter) {
38             return -1;
39         } else if (!aStartsWithLetter && bStartsWithLetter) {
40             return 1;
41         }
42 
43         // Order by the title in the current locale
44         return mCollator.compare(titleA, titleB);
45     }
46 }
47