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 {}