/**
* Copyright 2010 Google Inc.
*
* 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.diffable.utils;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.nio.ByteBuffer;
import java.nio.channels.Channel;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
/**
* IO utilities methods.
*
* @author ibrahim Chaehoi
*/
public class IOUtils {
/** the buffer size for reading data */
public static final int BUFFER_SIZE = 16384;
/**
* Writes all the contents of a Reader to a Writer.
*
* @param reader the reader to read from
* @param writer the writer to write to
*/
public static void copy(Reader reader, Writer writer) throws IOException {
copy(reader, writer, false);
}
/**
* Writes all the contents of a Reader to a Writer.
*
* @param reader the reader to read from
* @param writer the writer to write to
* @param closeStreams the flag indicating if the stream must be close at the end, even if an exception occurs
*/
public static void copy(Reader reader, Writer writer, boolean closeStreams) throws IOException {
char[] buf = new char[BUFFER_SIZE];
int num = 0;
try{
while ((num = reader.read(buf, 0, buf.length)) != -1) {
writer.write(buf, 0, num);
}
} finally {
if (closeStreams) {
close(reader);
close(writer);
}
}
}
/**
* Writes all the contents of a Reader to a Writer.
*
* @param reader the reader to read from
* @param writer the writer to write to
*/
public static void copy(InputStream input, OutputStream output)
throws IOException {
byte[] buf = new byte[BUFFER_SIZE];
int num = 0;
while ((num = input.read(buf, 0, buf.length)) != -1) {
output.write(buf, 0, num);
}
}
/**
* Writes all the contents of an InputStream to a Writer.
*
* @param input the input stream to read from
* @param writer the writer to write to
*/
public static void copy(InputStream input, Writer writer)
throws IOException {
copy(new InputStreamReader(input), writer);
}
/**
* Writes all the contents of an InputStream to an OutStream.
*
* @param input the input stream to read from
* @param output the output stream to write to
* @param closeStreams the flag indicating if the stream must be close at the end, even if an exception occurs
*/
public static void copy(InputStream input, OutputStream output,
boolean closeStreams) throws IOException {
try {
copy(input, output);
} finally {
if (closeStreams) {
close(input);
close(output);
}
}
}
/**
* Copy the readable byte channel to the writable byte channel
*
* @param inChannel the readable byte channel
* @param outChannel the writable byte channel
* @throws IOException if an IOException occurs.
*/
public static void copy(ReadableByteChannel inChannel,
WritableByteChannel outChannel) throws IOException {
if (inChannel instanceof FileChannel) {
((FileChannel) inChannel).transferTo(0, ((FileChannel) inChannel)
.size(), outChannel);
} else {
final ByteBuffer buffer = ByteBuffer.allocateDirect(16 * 1024);
try {
while (inChannel.read(buffer) != -1) {
// prepare the buffer to be drained
buffer.flip();
// write to the channel, may block
outChannel.write(buffer);
// If partial transfer, shift remainder down
// If buffer is empty, same as doing clear()
buffer.compact();
}
// EOF will leave buffer in fill state
buffer.flip();
// make sure the buffer is fully drained.
while (buffer.hasRemaining()) {
outChannel.write(buffer);
}
} finally {
IOUtils.close(inChannel);
IOUtils.close(outChannel);
}
}
}
/**
* Close the input stream
*
* @param stream the input stream to close
*/
public static void close(InputStream stream) {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
// Nothing to do
}
}
}
/**
* Close the output stream
*
* @param stream the output stream to close
*/
public static void close(OutputStream stream) {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
// Nothing to do
}
}
}
/**
* Close the channel
*
* @param channel the channel to close
*/
public static void close(Channel channel) {
if (channel != null) {
try {
channel.close();
} catch (IOException e) {
// Nothing to do
}
}
}
/**
* Close the reader
* @param reader the reader to close
*/
public static void close(Reader reader) {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
// Nothing to do
}
}
}
/**
* Close the writer
* @param writer the writer to close
*/
public static void close(Writer writer) {
if (writer != null) {
try {
writer.close();
} catch (IOException e) {
// Nothing to do
}
}
}
}