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/*
* Copyright 2013-2016 ksyun.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://ksyun.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.ksc.util;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.ksc.internal.Releasable;
/**
* 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.
* Caller is responsible for closing the given input stream.
*/
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.
* Caller is responsible for closing the given input stream.
*/
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}.
*
* For example, the creation of a 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
* 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();
}
}
/**
* Copies all bytes from the given input stream to the given output stream.
* Caller is responsible for closing the streams.
*
* @throws IOException
* if there is any IO exception during read or write.
*/
public static long copy(InputStream in, OutputStream out)
throws IOException {
byte[] buf = new byte[BUFFER_SIZE];
long count = 0;
int n = 0;
while ((n = in.read(buf)) > -1) {
out.write(buf, 0, n);
count += n;
}
return count;
}
}