Java tutorial
/* * Copyright 2013-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file 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.amazonaws.client.util.sdk; import java.io.ByteArrayOutputStream; import java.io.Closeable; import java.io.IOException; import java.io.InputStream; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.amazonaws.stringutil.StringUtils; /** * Utilities for IO operations. */ public enum IOUtils { ; private static final int BUFFER_SIZE = 1024 * 4; private static final Log defaultLog = LogFactory.getLog(IOUtils.class); /** * Reads and returns the rest of the given input stream as a byte array, * closing the input stream afterwards. */ public static byte[] toByteArray(InputStream is) throws IOException { ByteArrayOutputStream output = new ByteArrayOutputStream(); try { byte[] b = new byte[BUFFER_SIZE]; int n = 0; while ((n = is.read(b)) != -1) { output.write(b, 0, n); } return output.toByteArray(); } finally { output.close(); } } /** * Reads and returns the rest of the given input stream as a string, * closing the input stream afterwards. */ public static String toString(InputStream is) throws IOException { return new String(toByteArray(is), StringUtils.UTF8); } /** * Closes the given Closeable quietly. * @param is the given closeable * @param log logger used to log any failure should the close fail */ public static void closeQuietly(Closeable is, Log log) { if (is != null) { try { is.close(); } catch (IOException ex) { Log logger = log == null ? defaultLog : log; if (logger.isDebugEnabled()) logger.debug("Ignore failure in closing the Closeable", ex); } } } /** * Releases the given {@link Closeable} especially if it was an instance of * {@link Releasable}. * <p> * For example, the creation of a {@link ResettableInputStream} would entail * physically opening a file. If the opened file is meant to be closed only * (in a finally block) by the very same code block that created it, then it * is necessary that the release method must not be called while the * execution is made in other stack frames. * * In such case, as other stack frames may inadvertently or indirectly call * the close method of the stream, the creator of the stream would need to * explicitly disable the accidental closing via * {@link ResettableInputStream#disableClose()}, so that the release method * becomes the only way to truly close the opened file. */ public static void release(Closeable is, Log log) { closeQuietly(is, log); if (is instanceof Releasable) { Releasable r = (Releasable) is; r.release(); } } }