1 /*
2  * Copyright (C) 2017 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 android.app.timezone;
17 
18 /**
19  * Shared code for android.app.timezone classes.
20  */
21 final class Utils {
Utils()22     private Utils() {}
23 
validateVersion(String type, int version)24     static int validateVersion(String type, int version) {
25         if (version < 0 || version > 999) {
26             throw new IllegalArgumentException("Invalid " + type + " version=" + version);
27         }
28         return version;
29     }
30 
validateRulesVersion(String type, String rulesVersion)31     static String validateRulesVersion(String type, String rulesVersion) {
32         validateNotNull(type, rulesVersion);
33 
34         if (rulesVersion.isEmpty()) {
35             throw new IllegalArgumentException(type + " must not be empty");
36         }
37         return rulesVersion;
38     }
39 
40     /** Validates that {@code object} is not null. Always returns {@code object}. */
validateNotNull(String type, T object)41     static <T> T validateNotNull(String type, T object) {
42         if (object == null) {
43             throw new NullPointerException(type + " == null");
44         }
45         return object;
46     }
47 
48     /**
49      * If {@code requireNotNull} is {@code true} calls {@link #validateNotNull(String, Object)},
50      * and {@link #validateNull(String, Object)} otherwise. Returns {@code object}.
51      */
validateConditionalNull(boolean requireNotNull, String type, T object)52     static <T> T validateConditionalNull(boolean requireNotNull, String type, T object) {
53         if (requireNotNull) {
54             return validateNotNull(type, object);
55         } else {
56             return validateNull(type, object);
57         }
58     }
59 
60     /** Validates that {@code object} is null. Always returns null. */
validateNull(String type, T object)61     static <T> T validateNull(String type, T object) {
62         if (object != null) {
63             throw new IllegalArgumentException(type + " != null");
64         }
65         return null;
66     }
67 }
68