Package org.apache.commons.io.channels

Class ByteArraySeekableByteChannel

java.lang.Object

org.apache.commons.io.channels.ByteArraySeekableByteChannel

All Implemented Interfaces:

Closeable, AutoCloseable, ByteChannel, Channel, ReadableByteChannel, SeekableByteChannel, WritableByteChannel

public class ByteArraySeekableByteChannel
extends Object
implements SeekableByteChannel

A SeekableByteChannel implementation backed by a byte array.

When used for writing, the internal buffer grows to accommodate incoming data. The natural size limit is the value of IOUtils.SOFT_MAX_ARRAY_LENGTH and it's not possible to set the position or truncate to a value bigger than that. The raw internal buffer is accessed via array().

Building a read-only channel from an existing byte array is supported with:

 try (ByteArraySeekableByteChannel channel = ByteArraySeekableByteChannel.builder()
               .setByteArray(...)
               .setOpenOptions(StandardOpenOption.READ)
               .get()) {
               // read from channel
 }
 

Since:

2.21.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ByteArraySeekableByteChannel.Builder	Builds for ByteArraySeekableByteChannel.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	closed
private byte[]	data
private final boolean	isWritable
private final ReentrantLock	lock
private long	position
private static final int	RESIZE_LIMIT
private int	size

Constructor Summary

Constructors

Modifier	Constructor	Description
	ByteArraySeekableByteChannel()	Constructs a new instance, with a default internal buffer capacity.
private	ByteArraySeekableByteChannel(byte[] data)
	ByteArraySeekableByteChannel(int size)	Constructs a new instance, with an internal buffer of the given capacity, in bytes.
private	ByteArraySeekableByteChannel(ByteArraySeekableByteChannel.Builder builder)

Method Summary

Modifier and Type	Method	Description
byte[]	array()	Gets the raw byte array backing this channel, this is not a copy.
static ByteArraySeekableByteChannel.Builder	builder()	Constructs a new builder for ByteArraySeekableByteChannel.
private void	checkOpen()
private void	checkRange(long newSize, String method)
private void	checkWritable()
void	close()
long	getSize()	Like size() but never throws ClosedChannelException.
boolean	isOpen()
long	position()
SeekableByteChannel	position(long newPosition)
int	read(ByteBuffer buf)
private void	resize(int newLength)
long	size()
byte[]	toByteArray()	Gets a copy of the data stored in this channel.
SeekableByteChannel	truncate(long newSize)
static ByteArraySeekableByteChannel	wrap(byte[] bytes)	Constructs a new channel backed directly by the given byte array.
int	write(ByteBuffer b)

Methods inherited from class java.lang.Object

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

Field Details

RESIZE_LIMIT

private static final int RESIZE_LIMIT

See Also:

• Constant Field Values

data

private byte[] data

closed

private volatile boolean closed

position

private long position

size

private int size

isWritable

private final boolean isWritable

lock

private final ReentrantLock lock

Constructor Details

ByteArraySeekableByteChannel

public ByteArraySeekableByteChannel()

Constructs a new instance, with a default internal buffer capacity.

The initial size and position of the channel are 0.

See Also:

• ByteArrayOutputStream()

ByteArraySeekableByteChannel

private ByteArraySeekableByteChannel(ByteArraySeekableByteChannel.Builder builder)
                              throws IOException

Throws:

IOException

ByteArraySeekableByteChannel

private ByteArraySeekableByteChannel(byte[] data)

ByteArraySeekableByteChannel

public ByteArraySeekableByteChannel(int size)

Constructs a new instance, with an internal buffer of the given capacity, in bytes.

The initial size and position of the channel are 0.

Parameters:

size - Capacity of the internal buffer to allocate, in bytes.

See Also:

• ByteArrayOutputStream(int)

Method Details

builder

public static ByteArraySeekableByteChannel.Builder builder()

Constructs a new builder for ByteArraySeekableByteChannel.

Returns:

a new builder for ByteArraySeekableByteChannel.

Since:

2.22.0

wrap

public static ByteArraySeekableByteChannel wrap(byte[] bytes)

Constructs a new channel backed directly by the given byte array.

The channel initially contains the full contents of the array, with its size set to bytes.length and its position set to 0.

Reads and writes operate on the shared array. If a write operation extends beyond the current capacity, the channel will automatically allocate a larger backing array and copy the existing contents.

Parameters:

bytes - The byte array to wrap, must not be null

Returns:

A new channel that uses the given array as its initial backing store.

Throws:

NullPointerException - If bytes is null

See Also:

• array()
• ByteArrayInputStream(byte[])

array

public byte[] array()

Gets the raw byte array backing this channel, this is not a copy.

NOTE: The returned buffer is not aligned with containing data, use size() to obtain the size of data stored in the buffer.

Returns:

internal byte array.

checkOpen

private void checkOpen()
                throws ClosedChannelException

Throws:

ClosedChannelException

checkRange

private void checkRange(long newSize,
 String method)

checkWritable

private void checkWritable()

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface Closeable

getSize

public long getSize()

Like size() but never throws ClosedChannelException.

Returns:

See size().

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

position

public long position()
              throws ClosedChannelException

Specified by:

position in interface SeekableByteChannel

Throws:

ClosedChannelException

position

public SeekableByteChannel position(long newPosition)
                             throws IOException

Specified by:

position in interface SeekableByteChannel

Throws:

IOException

read

public int read(ByteBuffer buf)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Specified by:

read in interface SeekableByteChannel

Throws:

IOException

resize

private void resize(int newLength)

size

public long size()
          throws ClosedChannelException

Specified by:

size in interface SeekableByteChannel

Throws:

ClosedChannelException

toByteArray

public byte[] toByteArray()

Gets a copy of the data stored in this channel.

The returned array is a copy of the internal buffer, sized to the actual data stored in this channel.

Returns:

a new byte array containing the data stored in this channel.

truncate

public SeekableByteChannel truncate(long newSize)
                             throws ClosedChannelException

Specified by:

truncate in interface SeekableByteChannel

Throws:

ClosedChannelException

write

public int write(ByteBuffer b)
          throws IOException

Specified by:

write in interface SeekableByteChannel

Specified by:

write in interface WritableByteChannel

Throws:

IOException