Package org.apache.derby.impl.drda

Class StandardEXTDTAReaderInputStream

java.lang.Object

java.io.InputStream

org.apache.derby.impl.drda.EXTDTAReaderInputStream

org.apache.derby.impl.drda.StandardEXTDTAReaderInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

final class StandardEXTDTAReaderInputStream
extends EXTDTAReaderInputStream

Implementation of InputStream which get EXTDTA from the DDMReader. This class can be used to stream LOBs from Network client to the Network server.

Field Summary

Fields

Modifier and Type	Field	Description
private java.io.ByteArrayInputStream	currentBuffer	Current data buffer
private long	length	Length of stream
private DDMReader	reader	DDMReader.
private long	remainingBytes	Remaining bytes in stream

Fields inherited from class org.apache.derby.impl.drda.EXTDTAReaderInputStream

isLayerBStream, readStatusByte

Constructor Summary

Constructors

Constructor	Description
StandardEXTDTAReaderInputStream(DDMReader reader, boolean readStatusByte)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	available()	Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
(package private) long	getLength()	Returns the number of bytes returned by this stream.
private void	nextBuffer()	Fetches the next buffer.
protected void	onClientSideStreamingError()	Cleans up and closes the stream.
int	read()	Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len)	Reads up to len bytes of data from the input stream into an array of bytes.

Methods inherited from class org.apache.derby.impl.drda.EXTDTAReaderInputStream

checkStatus, getStatus, isLayerBStream, isStatusSet, setSuppressException, throwEXTDTATransferException

Methods inherited from class java.io.InputStream

close, mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, skip, transferTo

Methods inherited from class java.lang.Object

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

Field Detail

length

private final long length

Length of stream

reader

private final DDMReader reader

DDMReader. Used to get more data.

remainingBytes

private long remainingBytes

Remaining bytes in stream

currentBuffer

private java.io.ByteArrayInputStream currentBuffer

Current data buffer

Constructor Detail

StandardEXTDTAReaderInputStream

StandardEXTDTAReaderInputStream(DDMReader reader,
                                boolean readStatusByte)
                         throws DRDAProtocolException

Constructor.

Parameters:

reader - The reader to get data from

readStatusByte - whether or not to read the trailing Derby-specific EXTDTA stream status byte

Throws:

DRDAProtocolException - if thrown while initializing current buffer.

Method Detail

read

public final int read()
               throws java.io.IOException

Reads the next byte of data from the input stream.

This subclass of InputStream implements this method by reading the next byte from the current buffer. If there is more data, it will be requested a new buffer from the DDMReader.

Specified by:

read in class java.io.InputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs.

See Also:

InputStream.read()

read

public final int read(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer. This subclass implements this method by calling this method on the current buffer, which is an instance of ByteArrayInputStream. If the current buffer does not have any data, it will be requested a new buffer from the DDMReader.

Overrides:

read in class java.io.InputStream

Parameters:

b - the buffer into which the data is read.

off - the start offset in array b at which the data is written.

len - the maximum number of bytes to read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

java.io.IOException - if an I/O error occurs.

java.lang.NullPointerException - if b is null.

See Also:

InputStream.read(byte[], int, int)

available

public final int available()

Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.

This subclass implements this method by calling available on the current buffer, which is a ByteInputStreamReader.

Overrides:

available in class java.io.InputStream

Returns:

the number of bytes that can be read from this input stream without blocking.

getLength

final long getLength()

Returns the number of bytes returned by this stream.

The length includes data which has been already read at the invocation time, but doesn't include any meta data (like the Derby-specific EXTDTA status byte).

Returns:

The number of bytes that will be returned by this stream.

nextBuffer

private void nextBuffer()
                 throws java.io.IOException

Fetches the next buffer.

Throws:

java.io.IOException - if fetching the buffer fails

onClientSideStreamingError

protected void onClientSideStreamingError()

Cleans up and closes the stream.

Specified by:

onClientSideStreamingError in class EXTDTAReaderInputStream