org.apache.hadoop.io
Class IOUtils

java.lang.Object
  org.apache.hadoop.io.IOUtils

public class IOUtils
extends Object

An utility class for I/O related functionality.

Nested Class Summary

static class

IOUtils.NullOutputStream /dev/null of OutputStreams.

Constructor Summary

IOUtils()

Method Summary

static void	cleanup(org.apache.commons.logging.Log log, Closeable... closeables) Close the Closeable objects and ignore any IOException or null pointers.
static void	closeSocket(Socket sock) Closes the socket ignoring IOException
static void	closeStream(Closeable stream) Closes the stream ignoring IOException.
static void	copyBytes(InputStream in, OutputStream out, Configuration conf) Copies from one stream to another.
static void	copyBytes(InputStream in, OutputStream out, Configuration conf, boolean close) Copies from one stream to another.
static void	copyBytes(InputStream in, OutputStream out, int buffSize) Copies from one stream to another.
static void	copyBytes(InputStream in, OutputStream out, int buffSize, boolean close) Copies from one stream to another.
static void	copyBytes(InputStream in, OutputStream out, long length, int bufferSize, boolean close) Copies the specified length of bytes from in to out.
static void	readFileChannelFully(FileChannel fileChannel, byte[] buf, int off, int len) Reads len bytes in a loop using the channel of the stream
static void	readFully(InputStream in, byte[] buf, int off, int len) Reads len bytes in a loop.
static void	skipFully(InputStream in, long len) Similar to readFully().
static int	wrappedReadForCompressedData(InputStream is, byte[] buf, int off, int len) Utility wrapper for reading from InputStream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IOUtils

public IOUtils()

Method Detail

copyBytes

public static void copyBytes(InputStream in,
                             OutputStream out,
                             int buffSize,
                             boolean close)
                      throws IOException

Copies from one stream to another.

Parameters:

in - InputStrem to read from

out - OutputStream to write to

buffSize - the size of the buffer

close - whether or not close the InputStream and OutputStream at the end. The streams are closed in the finally clause.

Throws:

IOException

copyBytes

public static void copyBytes(InputStream in,
                             OutputStream out,
                             int buffSize)
                      throws IOException

Copies from one stream to another.

Parameters:

in - InputStrem to read from

out - OutputStream to write to

buffSize - the size of the buffer

Throws:

IOException

copyBytes

public static void copyBytes(InputStream in,
                             OutputStream out,
                             Configuration conf)
                      throws IOException

Copies from one stream to another. closes the input and output streams at the end.

Parameters:

in - InputStrem to read from

out - OutputStream to write to

conf - the Configuration object

Throws:

IOException

copyBytes

public static void copyBytes(InputStream in,
                             OutputStream out,
                             Configuration conf,
                             boolean close)
                      throws IOException

Copies from one stream to another.

Parameters:

in - InputStrem to read from

out - OutputStream to write to

conf - the Configuration object

close - whether or not close the InputStream and OutputStream at the end. The streams are closed in the finally clause.

Throws:

IOException

copyBytes

public static void copyBytes(InputStream in,
                             OutputStream out,
                             long length,
                             int bufferSize,
                             boolean close)
                      throws IOException

Copies the specified length of bytes from in to out.

Parameters:

in - InputStream to read from

out - OutputStream to write to

length - number of bytes to copy

bufferSize - the size of the buffer

close - whether to close the streams

Throws:

IOException - if bytes can not be read or written

wrappedReadForCompressedData

public static int wrappedReadForCompressedData(InputStream is,
                                               byte[] buf,
                                               int off,
                                               int len)
                                        throws IOException

Utility wrapper for reading from InputStream. It catches any errors thrown by the underlying stream (either IO or decompression-related), and re-throws as an IOException.

Parameters:

is - - InputStream to be read from

buf - - buffer the data is read into

off - - offset within buf

len - - amount of data to be read

Returns:

number of bytes read

Throws:

IOException

readFully

public static void readFully(InputStream in,
                             byte[] buf,
                             int off,
                             int len)
                      throws IOException

Reads len bytes in a loop.

Parameters:

in - The InputStream to read from

buf - The buffer to fill

off - offset from the buffer

len - the length of bytes to read

Throws:

IOException - if it could not read requested number of bytes for any reason (including EOF)

readFileChannelFully

public static void readFileChannelFully(FileChannel fileChannel,
                                        byte[] buf,
                                        int off,
                                        int len)
                                 throws IOException

Reads len bytes in a loop using the channel of the stream

Parameters:

fileChannel - a FileChannel to read len bytes into buf

buf - The buffer to fill

off - offset from the buffer

len - the length of bytes to read

Throws:

IOException - if it could not read requested number of bytes for any reason (including EOF)

skipFully

public static void skipFully(InputStream in,
                             long len)
                      throws IOException

Similar to readFully(). Skips bytes in a loop.

Parameters:

in - The InputStream to skip bytes from

len - number of bytes to skip.

Throws:

IOException - if it could not skip requested number of bytes for any reason (including EOF)

cleanup

public static void cleanup(org.apache.commons.logging.Log log,
                           Closeable... closeables)

Close the Closeable objects and ignore any IOException or null pointers. Must only be used for cleanup in exception handlers.

Parameters:

log - the log to record problems to at debug level. Can be null.

closeables - the objects to close

closeStream

public static void closeStream(Closeable stream)

Closes the stream ignoring IOException. Must only be called in cleaning up from exception handlers.

Parameters:

stream - the Stream to close

closeSocket

public static void closeSocket(Socket sock)

Closes the socket ignoring IOException

Parameters:

sock - the Socket to close