org.ballerinalang.nativeimpl.io.channels.base

Class Channel

java.lang.Object

org.ballerinalang.nativeimpl.io.channels.base.Channel

Direct Known Subclasses:

Base64Wrapper, BlobIOChannel, FileIOChannel, SocketIOChannel

public abstract class Channel
extends Object

Represents Ballerina Byte Channel.

Allows reading/writing bytes to perform I/O operations.

The bytes are read through the channel into the buffer. This will manage the buffer and the channel to deliver bytes I/O reading/writing APIs.

Constructor Summary

Constructors

Constructor and Description
Channel(ByteChannel channel, Reader reader, Writer writer) Will read/write bytes from the provided channel
Channel(ByteChannel channel, Reader reader, Writer writer, int size) Creates a channel which will contain a fixed sized buffer.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the given channel.
InputStream	getInputStream() This will return InputStream from underlying ByteChannel.
boolean	hasReachedEnd() Specifies whether the channel has reached to it's end.
int	read(ByteBuffer buffer) Async read bytes from the channel.
byte[]	readFull(int numberOfBytes) Reads specified amount of bytes from a given channel.
abstract void	transfer(int position, int count, WritableByteChannel dstChannel) Will be used when performing direct transfer operations from OS cache.
int	write(ByteBuffer content) Writes provided buffer content to the channel.

Methods inherited from class java.lang.Object

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

Constructor Detail

Channel

public Channel(ByteChannel channel,
               Reader reader,
               Writer writer)
        throws BallerinaIOException

Will read/write bytes from the provided channel

This operation will asynchronously read data from the channel.

Parameters:

channel - which will be used to read/write content.

reader - will be used for reading content.

writer - will be used for writing content.

Throws:

BallerinaIOException - initialization error.

Channel

public Channel(ByteChannel channel,
               Reader reader,
               Writer writer,
               int size)
        throws BallerinaIOException

Creates a channel which will contain a fixed sized buffer.

This operation will in turn request for excess bytes than required. And buffer the content. Also this will mostly be used with blocking readers and writers.

Parameters:

channel - which will be used to read/write content.

reader - will be used for reading content.

writer - will be used for writing content.

size - the size of the fixed buffer.

Throws:

BallerinaIOException - initialization error.

Method Detail

transfer

public abstract void transfer(int position,
                              int count,
                              WritableByteChannel dstChannel)
                       throws IOException

Will be used when performing direct transfer operations from OS cache.

Parameters:

position - starting position of the bytes to be transferred.

count - number of bytes to be transferred.

dstChannel - destination channel to transfer.

Throws:

IOException - during I/O error.

hasReachedEnd

public boolean hasReachedEnd()

Specifies whether the channel has reached to it's end.

Returns:

true if the channel has reached to it's end

read

public int read(ByteBuffer buffer)
         throws IOException

Async read bytes from the channel.

Parameters:

buffer - the buffer which will hold the content.

Returns:

the number of bytes read.

Throws:

IOException - errors occur during reading from channel.

write

public int write(ByteBuffer content)
          throws IOException

Writes provided buffer content to the channel.

Parameters:

content - the buffer which holds the content.

Returns:

the number of bytes written to the channel.

Throws:

IOException - errors occur during writing data to channel.

getInputStream

public InputStream getInputStream()
                           throws BallerinaIOException

This will return InputStream from underlying ByteChannel.

Returns:

An InputStream

Throws:

BallerinaIOException - error occur during obtaining input-stream.

readFull

public byte[] readFull(int numberOfBytes)
                throws IOException

Reads specified amount of bytes from a given channel.

Each time this method is called the data will be retrieved from the channels last read position.

Note : This operation cannot be called in parallel invocations since the underlying ByteBuffer and the channel are not synchronous.

Parameters:

numberOfBytes - the number of bytes required.

Returns:

bytes which are retrieved from the channel.

Throws:

IOException - during I/O error.

close

public void close()
           throws IOException

Closes the given channel.

Throws:

IOException - errors occur while closing the connection.