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 */
16package android.support.annotation;
17
18import static java.lang.annotation.ElementType.METHOD;
19import static java.lang.annotation.RetentionPolicy.CLASS;
20
21import java.lang.annotation.Documented;
22import java.lang.annotation.Retention;
23import java.lang.annotation.Target;
24
25/**
26 * Denotes that the annotated method returns a result that it typically is
27 * an error to ignore. This is usually used for methods that have no side effect,
28 * so calling it without actually looking at the result usually means the developer
29 * has misunderstood what the method does.
30 * <p>
31 * Example:
32 * <pre>{@code
33 *  public @CheckResult String trim(String s) { return s.trim(); }
34 *  ...
35 *  s.trim(); // this is probably an error
36 *  s = s.trim(); // ok
37 * }</pre>
38 */
39@Documented
40@Retention(CLASS)
41@Target({METHOD})
42public @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     *  &#64;CheckResult(suggest="#redirectErrorStream(boolean)")
54     *  public boolean redirectErrorStream() { ... }
55     * </pre>
56     */
57    String suggest() default "";
58}