shollander commented on a change in pull request #215: URL: https://github.com/apache/commons-io/pull/215#discussion_r709178300
########## File path: src/main/java/org/apache/commons/io/input/MemoryMappedFileInputStream.java ########## @@ -0,0 +1,169 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.commons.io.input; + +import static org.apache.commons.io.IOUtils.EOF; + +import java.io.BufferedInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.nio.ByteBuffer; +import java.nio.channels.FileChannel; +import java.nio.channels.FileChannel.MapMode; +import java.nio.file.Path; +import java.nio.file.StandardOpenOption; + +/** + * <p> + * An {@link InputStream} that utilizes memory mapped files to improve + * performance. A sliding window of the file is mapped to memory to avoid + * mapping the entire file to memory at one time. The size of the sliding buffer + * is user configurable. + * </p> + * <p> + * For most operating systems, mapping a file into memory is more expensive than + * reading or writing a few tens of kilobytes of data. From the standpoint of + * performance it is generally only worth mapping relatively large files into + * memory. + * </p> + * Note: Use of this class does not necessarily obviate the need to use a + * {@link BufferedInputStream}. Depending on the use case, the use of buffering + * may still further improve performance. For example: + * + * <pre> + * new BufferedInputStream(new GzipInputStream(new MemoryMappedFileInputStream(path)))) + * </pre> + * + * will greatly outperform: + * + * <pre> + * new GzipInputStream(new MemoryMappedFileInputStream(path)) + * </pre> + * + * @since 2.10.0 Review comment: fixed. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
