| /* |
| * Copyright (C) 2007 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.common.io; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.annotations.VisibleForTesting; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.Reader; |
| import java.util.logging.Level; |
| import java.util.logging.Logger; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Utility methods for working with {@link Closeable} objects. |
| * |
| * @author Michael Lancaster |
| * @since 1.0 |
| */ |
| @Beta |
| public final class Closeables { |
| @VisibleForTesting static final Logger logger |
| = Logger.getLogger(Closeables.class.getName()); |
| |
| private Closeables() {} |
| |
| /** |
| * Closes a {@link Closeable}, with control over whether an {@code IOException} may be thrown. |
| * This is primarily useful in a finally block, where a thrown exception needs to be logged but |
| * not propagated (otherwise the original exception will be lost). |
| * |
| * <p>If {@code swallowIOException} is true then we never throw {@code IOException} but merely log |
| * it. |
| * |
| * <p>Example: <pre> {@code |
| * |
| * public void useStreamNicely() throws IOException { |
| * SomeStream stream = new SomeStream("foo"); |
| * boolean threw = true; |
| * try { |
| * // ... code which does something with the stream ... |
| * threw = false; |
| * } finally { |
| * // If an exception occurs, rethrow it only if threw==false: |
| * Closeables.close(stream, threw); |
| * } |
| * }}</pre> |
| * |
| * @param closeable the {@code Closeable} object to be closed, or null, in which case this method |
| * does nothing |
| * @param swallowIOException if true, don't propagate IO exceptions thrown by the {@code close} |
| * methods |
| * @throws IOException if {@code swallowIOException} is false and {@code close} throws an |
| * {@code IOException}. |
| */ |
| public static void close(@Nullable Closeable closeable, |
| boolean swallowIOException) throws IOException { |
| if (closeable == null) { |
| return; |
| } |
| try { |
| closeable.close(); |
| } catch (IOException e) { |
| if (swallowIOException) { |
| logger.log(Level.WARNING, |
| "IOException thrown while closing Closeable.", e); |
| } else { |
| throw e; |
| } |
| } |
| } |
| |
| /** |
| * Closes the given {@link InputStream}, logging any {@code IOException} that's thrown rather |
| * than propagating it. |
| * |
| * <p>While it's not safe in the general case to ignore exceptions that are thrown when closing |
| * an I/O resource, it should generally be safe in the case of a resource that's being used only |
| * for reading, such as an {@code InputStream}. Unlike with writable resources, there's no |
| * chance that a failure that occurs when closing the stream indicates a meaningful problem such |
| * as a failure to flush all bytes to the underlying resource. |
| * |
| * @param inputStream the input stream to be closed, or {@code null} in which case this method |
| * does nothing |
| * @since 17.0 |
| */ |
| public static void closeQuietly(@Nullable InputStream inputStream) { |
| try { |
| close(inputStream, true); |
| } catch (IOException impossible) { |
| throw new AssertionError(impossible); |
| } |
| } |
| |
| /** |
| * Closes the given {@link Reader}, logging any {@code IOException} that's thrown rather than |
| * propagating it. |
| * |
| * <p>While it's not safe in the general case to ignore exceptions that are thrown when closing |
| * an I/O resource, it should generally be safe in the case of a resource that's being used only |
| * for reading, such as a {@code Reader}. Unlike with writable resources, there's no chance that |
| * a failure that occurs when closing the reader indicates a meaningful problem such as a failure |
| * to flush all bytes to the underlying resource. |
| * |
| * @param reader the reader to be closed, or {@code null} in which case this method does nothing |
| * @since 17.0 |
| */ |
| public static void closeQuietly(@Nullable Reader reader) { |
| try { |
| close(reader, true); |
| } catch (IOException impossible) { |
| throw new AssertionError(impossible); |
| } |
| } |
| } |