Tor Norbye | cb59f2a | 2015-03-02 07:55:51 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 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.annotation; |
| 17 | |
| 18 | import java.lang.annotation.Retention; |
| 19 | import java.lang.annotation.Target; |
| 20 | |
| 21 | import static java.lang.annotation.ElementType.METHOD; |
| 22 | import static java.lang.annotation.RetentionPolicy.SOURCE; |
| 23 | |
| 24 | /** |
| 25 | * Denotes that the annotated method returns a result that it typically is |
| 26 | * an error to ignore. This is usually used for methods that have no side effect, |
| 27 | * so calling it without actually looking at the result usually means the developer |
| 28 | * has misunderstood what the method does. |
| 29 | * <p> |
| 30 | * Example: |
| 31 | * <pre>{@code |
Neil Fuller | 71fbb81 | 2015-11-30 09:51:33 +0000 | [diff] [blame] | 32 | * public @CheckResult String trim(String s) { return s.trim(); } |
Tor Norbye | cb59f2a | 2015-03-02 07:55:51 -0800 | [diff] [blame] | 33 | * ... |
| 34 | * s.trim(); // this is probably an error |
| 35 | * s = s.trim(); // ok |
| 36 | * }</pre> |
| 37 | * |
| 38 | * @hide |
| 39 | */ |
| 40 | @Retention(SOURCE) |
| 41 | @Target({METHOD}) |
| 42 | public @interface CheckResult { |
| 43 | /** Defines the name of the suggested method to use instead, if applicable (using |
| 44 | * the same signature format as javadoc.) If there is more than one possibility, |
| 45 | * list them all separated by commas. |
| 46 | * <p> |
| 47 | * For example, ProcessBuilder has a method named {@code redirectErrorStream()} |
| 48 | * which sounds like it might redirect the error stream. It does not. It's just |
| 49 | * a getter which returns whether the process builder will redirect the error stream, |
| 50 | * and to actually set it, you must call {@code redirectErrorStream(boolean)}. |
| 51 | * In that case, the method should be defined like this: |
| 52 | * <pre> |
| 53 | * @CheckResult(suggest="#redirectErrorStream(boolean)") |
| 54 | * public boolean redirectErrorStream() { ... } |
| 55 | * </pre> |
| 56 | */ |
| 57 | String suggest() default ""; |
| 58 | } |