org.apache.flink.util.IOUtils Maven / Gradle / Ivy
/*
* 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.flink.util;
import org.slf4j.Logger;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
/**
* An utility class for I/O related functionality.
*/
public final class IOUtils {
/** The block size for byte operations in byte. */
private static final int BLOCKSIZE = 4096;
// ------------------------------------------------------------------------
// Byte copy operations
// ------------------------------------------------------------------------
/**
* Copies from one stream to another.
*
* @param in
* InputStream to read from
* @param out
* OutputStream to write to
* @param buffSize
* the size of the buffer
* @param close
* whether or not close the InputStream and OutputStream at the end. The streams are closed in the finally
* clause.
* @throws IOException
* thrown if an error occurred while writing to the output stream
*/
public static void copyBytes(final InputStream in, final OutputStream out, final int buffSize, final boolean close)
throws IOException {
@SuppressWarnings("resource")
final PrintStream ps = out instanceof PrintStream ? (PrintStream) out : null;
final byte[] buf = new byte[buffSize];
try {
int bytesRead = in.read(buf);
while (bytesRead >= 0) {
out.write(buf, 0, bytesRead);
if ((ps != null) && ps.checkError()) {
throw new IOException("Unable to write to output stream.");
}
bytesRead = in.read(buf);
}
} finally {
if (close) {
out.close();
in.close();
}
}
}
/**
* Copies from one stream to another. closes the input and output
* streams at the end.
*
* @param in
* InputStream to read from
* @param out
* OutputStream to write to
* @throws IOException
* thrown if an I/O error occurs while copying
*/
public static void copyBytes(final InputStream in, final OutputStream out) throws IOException {
copyBytes(in, out, BLOCKSIZE, true);
}
/**
* Copies from one stream to another.
*
* @param in
* InputStream to read from
* @param out
* OutputStream to write to
* @param close
* whether or not close the InputStream and OutputStream at the
* end. The streams are closed in the finally clause.
* @throws IOException
* thrown if an I/O error occurs while copying
*/
public static void copyBytes(final InputStream in, final OutputStream out, final boolean close) throws IOException {
copyBytes(in, out, BLOCKSIZE, close);
}
// ------------------------------------------------------------------------
// Stream input skipping
// ------------------------------------------------------------------------
/**
* Reads len bytes in a loop.
*
* @param in
* The InputStream to read from
* @param buf
* The buffer to fill
* @param off
* offset from the buffer
* @param len
* the length of bytes to read
* @throws IOException
* if it could not read requested number of bytes for any reason (including EOF)
*/
public static void readFully(final InputStream in, final byte[] buf, int off, final int len)
throws IOException {
int toRead = len;
while (toRead > 0) {
final int ret = in.read(buf, off, toRead);
if (ret < 0) {
throw new IOException("Premeture EOF from inputStream");
}
toRead -= ret;
off += ret;
}
}
/**
* Similar to readFully(). Skips bytes in a loop.
*
* @param in
* The InputStream to skip bytes from
* @param len
* number of bytes to skip
* @throws IOException
* if it could not skip requested number of bytes for any reason (including EOF)
*/
public static void skipFully(final InputStream in, long len) throws IOException {
while (len > 0) {
final long ret = in.skip(len);
if (ret < 0) {
throw new IOException("Premeture EOF from inputStream");
}
len -= ret;
}
}
// ------------------------------------------------------------------------
// Silent I/O cleanup / closing
// ------------------------------------------------------------------------
/**
* Close the AutoCloseable objects and ignore any {@link Exception} or
* null pointers. Must only be used for cleanup in exception handlers.
*
* @param log
* the log to record problems to at debug level. Can be null.
* @param closeables
* the objects to close
*/
public static void cleanup(final Logger log, final AutoCloseable... closeables) {
for (AutoCloseable c : closeables) {
if (c != null) {
try {
c.close();
} catch (Exception e) {
if (log != null && log.isDebugEnabled()) {
log.debug("Exception in closing " + c, e);
}
}
}
}
}
/**
* Closes the stream ignoring {@link IOException}. Must only be called in
* cleaning up from exception handlers.
*
* @param stream
* the stream to close
*/
public static void closeStream(final java.io.Closeable stream) {
cleanup(null, stream);
}
/**
* Closes the socket ignoring {@link IOException}.
*
* @param sock
* the socket to close
*/
public static void closeSocket(final Socket sock) {
// avoids try { close() } dance
if (sock != null) {
try {
sock.close();
} catch (IOException ignored) {
}
}
}
/**
* Closes all {@link AutoCloseable} objects in the parameter, suppressing exceptions. Exception will be emitted
* after calling close() on every object.
*
* @param closeables iterable with closeables to close.
* @throws Exception collected exceptions that occurred during closing
*/
public static void closeAll(Iterable closeables) throws Exception {
if (null != closeables) {
Exception collectedExceptions = null;
for (AutoCloseable closeable : closeables) {
try {
if (null != closeable) {
closeable.close();
}
} catch (Exception e) {
collectedExceptions = ExceptionUtils.firstOrSuppressed(e, collectedExceptions);
}
}
if (null != collectedExceptions) {
throw collectedExceptions;
}
}
}
/**
* Closes all elements in the iterable with closeQuietly().
*/
public static void closeAllQuietly(Iterable closeables) {
if (null != closeables) {
for (AutoCloseable closeable : closeables) {
closeQuietly(closeable);
}
}
}
/**
* Closes the given AutoCloseable.
*
* Important: This method is expected to never throw an exception.
*/
public static void closeQuietly(AutoCloseable closeable) {
try {
if (closeable != null) {
closeable.close();
}
} catch (Throwable ignored) {}
}
// ------------------------------------------------------------------------
/**
* Private constructor to prevent instantiation.
*/
private IOUtils() {}
}
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