001/*
002 * Copyright 2016 The Error Prone Authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.errorprone.annotations;
018
019import static java.lang.annotation.ElementType.CONSTRUCTOR;
020import static java.lang.annotation.ElementType.METHOD;
021import static java.lang.annotation.RetentionPolicy.SOURCE;
022
023import java.lang.annotation.Documented;
024import java.lang.annotation.Retention;
025import java.lang.annotation.Target;
026
027/**
028 * Annotation for constructors of AutoCloseables or methods that return an AutoCloseable and require
029 * that the resource is closed.
030 *
031 * <p>This is enforced by checking that invocations occur within the resource variable initializer
032 * of a try-with-resources statement, which guarantees that the resource is always closed. The
033 * analysis may be improved in the future to recognize other patterns where the resource will always
034 * be closed.
035 *
036 * <p>Note that Android SDK versions prior to 19 do not support try-with-resources, so the
037 * annotation should be avoided on APIs that may be used on Android, unless desugaring is used.
038 */
039@Documented
040@Retention(SOURCE)
041@Target({CONSTRUCTOR, METHOD})
042public @interface MustBeClosed {}