| /* |
| * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang; |
| |
| /** |
| * An object that may hold resources (such as file or socket handles) |
| * until it is closed. The {@link #close()} method of an {@code AutoCloseable} |
| * object is called automatically when exiting a {@code |
| * try}-with-resources block for which the object has been declared in |
| * the resource specification header. This construction ensures prompt |
| * release, avoiding resource exhaustion exceptions and errors that |
| * may otherwise occur. |
| * |
| * @apiNote |
| * <p>It is possible, and in fact common, for a base class to |
| * implement AutoCloseable even though not all of its subclasses or |
| * instances will hold releasable resources. For code that must operate |
| * in complete generality, or when it is known that the {@code AutoCloseable} |
| * instance requires resource release, it is recommended to use {@code |
| * try}-with-resources constructions. However, when using facilities such as |
| * {@link java.util.stream.Stream} that support both I/O-based and |
| * non-I/O-based forms, {@code try}-with-resources blocks are in |
| * general unnecessary when using non-I/O-based forms. |
| * |
| * @author Josh Bloch |
| * @since 1.7 |
| */ |
| public interface AutoCloseable { |
| /** |
| * Closes this resource, relinquishing any underlying resources. |
| * This method is invoked automatically on objects managed by the |
| * {@code try}-with-resources statement. |
| * |
| * <p>While this interface method is declared to throw {@code |
| * Exception}, implementers are <em>strongly</em> encouraged to |
| * declare concrete implementations of the {@code close} method to |
| * throw more specific exceptions, or to throw no exception at all |
| * if the close operation cannot fail. |
| * |
| * <p> Cases where the close operation may fail require careful |
| * attention by implementers. It is strongly advised to relinquish |
| * the underlying resources and to internally <em>mark</em> the |
| * resource as closed, prior to throwing the exception. The {@code |
| * close} method is unlikely to be invoked more than once and so |
| * this ensures that the resources are released in a timely manner. |
| * Furthermore it reduces problems that could arise when the resource |
| * wraps, or is wrapped, by another resource. |
| * |
| * <p><em>Implementers of this interface are also strongly advised |
| * to not have the {@code close} method throw {@link |
| * InterruptedException}.</em> |
| * |
| * This exception interacts with a thread's interrupted status, |
| * and runtime misbehavior is likely to occur if an {@code |
| * InterruptedException} is {@linkplain Throwable#addSuppressed |
| * suppressed}. |
| * |
| * More generally, if it would cause problems for an |
| * exception to be suppressed, the {@code AutoCloseable.close} |
| * method should not throw it. |
| * |
| * <p>Note that unlike the {@link java.io.Closeable#close close} |
| * method of {@link java.io.Closeable}, this {@code close} method |
| * is <em>not</em> required to be idempotent. In other words, |
| * calling this {@code close} method more than once may have some |
| * visible side effect, unlike {@code Closeable.close} which is |
| * required to have no effect if called more than once. |
| * |
| * However, implementers of this interface are strongly encouraged |
| * to make their {@code close} methods idempotent. |
| * |
| * @throws Exception if this resource cannot be closed |
| */ |
| void close() throws Exception; |
| } |