001/* 002 * Portions of this software was developed by employees of the National Institute 003 * of Standards and Technology (NIST), an agency of the Federal Government and is 004 * being made available as a public service. Pursuant to title 17 United States 005 * Code Section 105, works of NIST employees are not subject to copyright 006 * protection in the United States. This software may be subject to foreign 007 * copyright. Permission in the United States and in foreign countries, to the 008 * extent that NIST may hold copyright, to use, copy, modify, create derivative 009 * works, and distribute this software and its documentation without fee is hereby 010 * granted on a non-exclusive basis, provided that this notice and disclaimer 011 * of warranty appears in all copies. 012 * 013 * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER 014 * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY 015 * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF 016 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM 017 * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE 018 * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE. IN NO EVENT 019 * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT, 020 * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM, 021 * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY, 022 * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR 023 * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT 024 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER. 025 */ 026 027package gov.nist.secauto.metaschema.core.util; 028 029import edu.umd.cs.findbugs.annotations.NonNull; 030import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; 031 032/** 033 * Wraps a resource to make it {@link AutoCloseable}. 034 * 035 * @param <T> 036 * the resource type 037 * @param <E> 038 * the exception type that may be thrown if an error occurs when 039 * closing the resource 040 */ 041public class AutoCloser<T, E extends Exception> implements AutoCloseable { 042 @NonNull 043 private final T resource; 044 @NonNull 045 private final Closer<T, E> closeLambda; 046 047 /** 048 * Adapt the the provided {@code resource} to be {@link AutoCloseable}, using a 049 * provided closer {@code lambda}. 050 * 051 * @param <T> 052 * the resource's type 053 * @param <E> 054 * the exception type that can be thrown when closing 055 * @param resource 056 * the object to adapt 057 * @param lambda 058 * the lambda to use as a callback on close 059 * @return the resource wrapped in an {@link AutoCloseable} 060 */ 061 @NonNull 062 public static <T, E extends Exception> AutoCloser<T, E> autoClose( 063 @NonNull T resource, 064 @NonNull Closer<T, E> lambda) { 065 return new AutoCloser<>(resource, lambda); 066 } 067 068 /** 069 * Adapt the provided {@code resource} to be {@link AutoCloseable}, using a 070 * provided closer {@code lambda}. 071 * 072 * @param resource 073 * the object to adapt 074 * @param lambda 075 * the lambda to use as a callback on close 076 */ 077 public AutoCloser(@NonNull T resource, @NonNull Closer<T, E> lambda) { 078 this.resource = resource; 079 this.closeLambda = lambda; 080 } 081 082 /** 083 * Get the wrapped resource. 084 * 085 * @return the resource object 086 */ 087 @NonNull 088 public T getResource() { 089 return resource; 090 } 091 092 @Override 093 @SuppressFBWarnings("THROWS_METHOD_THROWS_CLAUSE_BASIC_EXCEPTION") 094 public void close() throws E { 095 closeLambda.close(getResource()); 096 } 097 098 @FunctionalInterface 099 public interface Closer<T, E extends Exception> { 100 /** 101 * This method is called to auto-close the resource. 102 * 103 * @param object 104 * the resource to auto-close 105 * @throws E 106 * the exception type that can be thrown when closing 107 */ 108 @SuppressFBWarnings("THROWS_METHOD_THROWS_CLAUSE_BASIC_EXCEPTION") 109 void close(@NonNull T object) throws E; 110 } 111}