Package emissary.core.channels

Class SeekableByteChannelHelper

java.lang.Object

emissary.core.channels.SeekableByteChannelHelper

public final class SeekableByteChannelHelper
extends Object

Helper methods to handle SeekableByteChannel objects

Field Summary

Fields

Modifier and Type	Field	Description
static SeekableByteChannelFactory	EMPTY_CHANNEL_FACTORY	Channel factory backed by an empty byte array.

Method Summary

Modifier and Type	Method	Description
static long	available(InputStream inputStream)	Provided with an existing input stream, check how far we can read into it.
static SeekableByteChannelFactory	file(Path path)	Create a file SBC factory.
static SeekableByteChannelFactory	fill(long size, byte value)	Create a fill SBC factory.
static byte[]	getByteArrayFromBdo(IBaseDataObject ibdo, int maxSize)	Given a BDO, create a byte array with as much data as possible.
static byte[]	getByteArrayFromChannel(SeekableByteChannelFactory sbcf, int maxSize)	Given a channel factory, create a byte array with as much data as possible.
static int	getFromInputStream(InputStream inputStream, ByteBuffer byteBuffer, long bytesToSkip)	Reads data from an input stream into a buffer
static SeekableByteChannelFactory	immutable(SeekableByteChannelFactory sbcf)	Make an existing factory immutable.
static SeekableByteChannelFactory	inputStream(long size, InputStreamFactory inputStreamFactory)	Create an InputStream SBC factory.
static SeekableByteChannelFactory	memory(byte[] bytes)	Create an in memory SBC factory which can be used to create any number of channels based on the provided bytes without storing them multiple times.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_CHANNEL_FACTORY

public static final SeekableByteChannelFactory EMPTY_CHANNEL_FACTORY

Channel factory backed by an empty byte array. Used for situations when a BDO should have its payload discarded.

Method Detail

immutable

public static SeekableByteChannelFactory immutable(SeekableByteChannelFactory sbcf)

Make an existing factory immutable.

Parameters:

sbcf - to make immutable

Returns:

the wrapped factory

memory

public static SeekableByteChannelFactory memory(byte[] bytes)

Create an in memory SBC factory which can be used to create any number of channels based on the provided bytes without storing them multiple times.

Parameters:

bytes - to use with the channel

Returns:

the factory

file

public static SeekableByteChannelFactory file(Path path)

Create a file SBC factory.

Parameters:

path - to the file.

Returns:

the factory

fill

public static SeekableByteChannelFactory fill(long size,
                                              byte value)

Create a fill SBC factory.

Parameters:

size - of the SeekableByteChannel

value - of each element in the SeekableByteChannel.

Returns:

the factory

inputStream

public static SeekableByteChannelFactory inputStream(long size,
                                                     InputStreamFactory inputStreamFactory)

Create an InputStream SBC factory.

Parameters:

size - of the SeekableByteChannel

inputStreamFactory - creates the needed InputStreams.

Returns:

the factory

getByteArrayFromBdo

public static byte[] getByteArrayFromBdo(IBaseDataObject ibdo,
                                         int maxSize)

Given a BDO, create a byte array with as much data as possible.

Parameters:

ibdo - to get the data from

maxSize - to limit the byte array to

Returns:

a byte array of the data from the BDO sized up to maxSize (so could truncate data)

getByteArrayFromChannel

public static byte[] getByteArrayFromChannel(SeekableByteChannelFactory sbcf,
                                             int maxSize)
                                      throws IOException

Given a channel factory, create a byte array with as much data as possible.

Parameters:

sbcf - to get the data from

maxSize - to limit the byte array to

Returns:

a byte array of the data from the factory sized up to maxSize (so could truncate data)

Throws:

IOException - if we couldn't read all the data

available

public static long available(InputStream inputStream)

Provided with an existing input stream, check how far we can read into it. Note that the inputStream is read as-is, so if the stream is not at the start, this method won't take that into account. If we can successfully read the stream, the position of the provided stream will of course change. Don't wrap the provided stream with anything such as BufferedInputStream as this will cause read errors prematurely, unless this is acceptable.

Parameters:

inputStream - to read - caller must handle closing this object

Returns:

position of last successful read (which could be the size of the stream)

getFromInputStream

public static int getFromInputStream(InputStream inputStream,
                                     ByteBuffer byteBuffer,
                                     long bytesToSkip)
                              throws IOException

Reads data from an input stream into a buffer

Parameters:

inputStream - to read from

byteBuffer - to read into

bytesToSkip - within the is to get to the next read location

Throws:

IOException - if an error occurs