Package org.apache.jackrabbit.oak.commons

Class IOUtils

java.lang.Object

org.apache.jackrabbit.oak.commons.IOUtils

public final class IOUtils
extends Object

Input/output utility methods.

Method Summary

Modifier and Type	Method	Description
static void	closeQuietly(Closeable closeable)	Unconditionally close a Closeable.
static void	closeQuietly(Socket sock)	Unconditionally close a Socket.
static long	copy(InputStream input, OutputStream output)	Copy bytes from an InputStream to an OutputStream.
static String	humanReadableByteCount(long bytes)	Returns a human-readable version of the file size, where the input represents a specific number of bytes.
static String	humanReadableByteCountBin(long bytes)	Returns a human-readable version of this byte count.
static long	nextPowerOf2(int x)	Get the value that is equal or higher than this value, and that is a power of two.
static byte[]	readBytes(InputStream in)	Read a byte array.
static int	readFully(InputStream in, byte[] buffer, int off, int max)	Try to read the given number of bytes to the buffer.
static int	readFully(FileChannel channel, int position, ByteBuffer buffer)	Try to read the given number of bytes starting at the specified position into the buffer.
static int	readInt(InputStream in)	Read an integer (4 bytes).
static long	readLong(InputStream in)	Read a long (8 bytes).
static String	readString(InputStream in)	Read a String.
static int	readVarInt(InputStream in)	Read a variable size integer.
static long	readVarLong(InputStream in)	Read a variable size long.
static void	skipFully(InputStream in, long skip)	Skip a number of bytes in an input stream.
static void	writeBytes(OutputStream out, byte[] data)	Write a byte array.
static void	writeInt(OutputStream out, int x)	Write an integer (4 bytes).
static void	writeLong(OutputStream out, long x)	Write a long (8 bytes).
static void	writeString(OutputStream out, String s)	Write a String.
static void	writeVarInt(OutputStream out, int x)	Write a variable size integer.
static void	writeVarLong(OutputStream out, long x)	Write a variable size long.

Methods inherited from class java.lang.Object

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

Method Detail

readFully

public static int readFully(InputStream in,
                            byte[] buffer,
                            int off,
                            int max)
                     throws IOException

Try to read the given number of bytes to the buffer. This method reads until the maximum number of bytes have been read or until the end of file.

Parameters:

in - the input stream

buffer - the output buffer

off - the offset in the buffer

max - the number of bytes to read at most

Returns:

the number of bytes read, 0 meaning EOF or no space in buffer

Throws:

IOException - If an error occurs.

readFully

public static int readFully(FileChannel channel,
                            int position,
                            ByteBuffer buffer)
                     throws IOException

Try to read the given number of bytes starting at the specified position into the buffer. This method reads until the maximum number of bytes have been read or until the end of the channel.

Parameters:

channel - the input channel

position - the position to start reading from the channel

buffer - the output buffer

Returns:

the number of bytes read, 0 meaning EOF or no space in buffer

Throws:

IOException - If an error occurs.

skipFully

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

Skip a number of bytes in an input stream.

Parameters:

in - the input stream

skip - the number of bytes to skip

Throws:

EOFException - if the end of file has been reached before all bytes could be skipped

IOException - if an IO exception occurred while skipping

writeString

public static void writeString(OutputStream out,
                               String s)
                        throws IOException

Write a String. This will first write the length as 4 bytes, and then the UTF-8 encoded string.

Parameters:

out - the data output stream

s - the string (maximum length about 2 GB)

Throws:

IOException - if an IO exception occurred while writing

readString

public static String readString(InputStream in)
                         throws IOException

Read a String. This will first read the length as 4 bytes, and then the UTF-8 encoded string.

Parameters:

in - the data input stream

Returns:

the string

Throws:

IOException - if an IO exception occurred while reading

writeBytes

public static void writeBytes(OutputStream out,
                              byte[] data)
                       throws IOException

Write a byte array. This will first write the length as 4 bytes, and then the actual bytes.

Parameters:

out - the data output stream

data - the byte array

Throws:

IOException - if an IO exception occurred while writing.

readBytes

public static byte[] readBytes(InputStream in)
                        throws IOException

Read a byte array. This will first read the length as 4 bytes, and then the actual bytes.

Parameters:

in - the data input stream

Returns:

the bytes

Throws:

IOException - if an IO exception occurred while reading from the stream.

writeVarInt

public static void writeVarInt(OutputStream out,
                               int x)
                        throws IOException

Write a variable size integer. Negative values need 5 bytes.

Parameters:

out - the output stream

x - the value

Throws:

IOException - if an IO exception occurred while writing.

readVarInt

public static int readVarInt(InputStream in)
                      throws IOException

Read a variable size integer.

Parameters:

in - the input stream

Returns:

the integer

Throws:

IOException - if an IO exception occurred while reading.

writeVarLong

public static void writeVarLong(OutputStream out,
                                long x)
                         throws IOException

Write a variable size long. Negative values need 10 bytes.

Parameters:

out - the output stream

x - the value

Throws:

IOException - if an IO exception occurred while writing.

writeLong

public static void writeLong(OutputStream out,
                             long x)
                      throws IOException

Write a long (8 bytes).

Parameters:

out - the output stream

x - the value

Throws:

IOException - if an IO exception occurred while writing.

readLong

public static long readLong(InputStream in)
                     throws IOException

Read a long (8 bytes).

Parameters:

in - the input stream

Returns:

the value

Throws:

IOException - if an IO exception occurred while reading.

writeInt

public static void writeInt(OutputStream out,
                            int x)
                     throws IOException

Write an integer (4 bytes).

Parameters:

out - the output stream

x - the value

Throws:

IOException - if an IO exception occurred while writing.

readInt

public static int readInt(InputStream in)
                   throws IOException

Read an integer (4 bytes).

Parameters:

in - the input stream

Returns:

the value

Throws:

IOException - if an IO exception occurred while reading.

readVarLong

public static long readVarLong(InputStream in)
                        throws IOException

Read a variable size long.

Parameters:

in - the input stream

Returns:

the long

Throws:

IOException - if an IO exception occurred while reading.

nextPowerOf2

public static long nextPowerOf2(int x)

Get the value that is equal or higher than this value, and that is a power of two. The returned value will be in the range [0, 2^31]. If the input is less than zero, the result of 1 is returned (powers of negative numbers are not integer values).

Parameters:

x - the original value.

Returns:

the next power of two value. Results are always in the range [0, 2^31].

closeQuietly

public static void closeQuietly(Closeable closeable)

Unconditionally close a Closeable.

Equivalent to Closeable.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

closeable - the object to close, may be null or already closed

closeQuietly

public static void closeQuietly(Socket sock)

Unconditionally close a Socket.

Equivalent to Socket.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

sock - the Socket to close, may be null or already closed

copy

public static long copy(InputStream input,
                        OutputStream output)
                 throws IOException

Copy bytes from an InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

IOException - if an I/O error occurs

humanReadableByteCount

public static String humanReadableByteCount(long bytes)

Returns a human-readable version of the file size, where the input represents a specific number of bytes. Based on http://stackoverflow.com/a/3758880/1035417

humanReadableByteCountBin

public static String humanReadableByteCountBin(long bytes)

Returns a human-readable version of this byte count. The result uses the binary system, that is, 1K = 1024. Based on https://stackoverflow.com/a/3758880/2071159.