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 */
16package android.icu.cts.coverage.rules;
17
18import android.icu.util.ULocale;
19import org.junit.rules.MethodRule;
20import org.junit.runners.model.FrameworkMethod;
21import org.junit.runners.model.Statement;
22
23/**
24 * Add this as a rule to a JUnit 4 class to support switching the {@link ULocale#getDefault()} for
25 * the duration of the test method.
26 *
27 * <p>Only affects test methods that are annotated with {@link ULocaleDefault}.
28 *
29 * @see ULocaleDefault
30 */
31@SuppressWarnings("deprecation")
32public class ULocaleDefaultRule implements MethodRule {
33
34    @Override
35    public Statement apply(final Statement base, FrameworkMethod method, Object target) {
36        final ULocaleDefault annotation = method.getAnnotation(ULocaleDefault.class);
37        if (annotation == null) {
38            return base;
39        } else {
40            return new Statement() {
41                @Override
42                public void evaluate() throws Throwable {
43                    ULocale previousDefault = ULocale.getDefault();
44                    try {
45                        ULocale.setDefault(ULocale.forLanguageTag(annotation.languageTag()));
46                        base.evaluate();
47                    } finally {
48                        ULocale.setDefault(previousDefault);
49                    }
50                }
51            };
52        }
53    }
54}
55