net.sourceforge.jtds.jdbc
Class ResponseStream

java.lang.Object
  net.sourceforge.jtds.jdbc.ResponseStream

public class ResponseStream

extends java.lang.Object

Implements an input stream for the server response.

Implementation note:

1. This class contains methods to read different types of data from the server response stream in TDS format.
2. Character translation of String items is carried out.

Version:

$Id: ResponseStream.java,v 1.20 2005/10/27 13:22:33 alin_sinpalean Exp $

Author:

Mike Hutchinson.

Nested Class Summary

private static class

ResponseStream.TdsInputStream Simple inner class implementing an InputStream over the server response.

Field Summary

private byte[]	buffer The Input packet buffer.
private int	bufferLen The length of current input packet.
private int	bufferPtr The offset of the next byte to read.
private byte[]	byteBuffer A shared byte buffer.
private char[]	charBuffer A shared char buffer.
private boolean	isClosed True if stream is closed.
private SharedSocket	socket The shared network socket.
private int	streamId The unique stream id.

Constructor Summary

(package private)

ResponseStream(SharedSocket socket, int streamId, int bufferSize) Constructs a RequestStream object.

Method Summary

(package private) void	close() Closes this response stream.
(package private) java.io.InputStream	getInputStream(int len) Creates a simple InputStream over the server response.
private void	getPacket() Read the next TDS packet from the network.
(package private) int	getServerType() Retrieves the server type.
(package private) int	getStreamId() Retrieves the unique stream id.
(package private) int	getTdsVersion() Retrieves the TDS version number.
(package private) int	peek() Retrieves the next input byte without reading forward.
(package private) int	read() Reads the next input byte from the server response stream.
(package private) int	read(byte[] b) Reads a byte array from the server response stream.
(package private) int	read(byte[] b, int off, int len) Reads a byte array from the server response stream, specifying a start offset and length.
(package private) int	read(char[] c) Reads a char array from the server response stream.
(package private) int	readInt() Reads an int value from the server response stream.
(package private) long	readLong() Reads a long value from the server response stream.
(package private) java.lang.String	readNonUnicodeString(int len) Reads a non Unicode String from the server response stream, creating the String from a translated byte array.
(package private) java.lang.String	readNonUnicodeString(int len, CharsetInfo charsetInfo) Reads a String from the server response stream, translating it from a byte array using the specified character set.
(package private) short	readShort() Reads a short value from the server response stream.
(package private) java.lang.String	readString(int len) Reads a String object from the server response stream.
(package private) java.lang.String	readString(int len, CharsetInfo info) Reads a String from the server response stream, creating it from a translated byte array.
(package private) java.lang.String	readUnicodeString(int len) Reads a UCS2-LE (Unicode) encoded String object from the server response stream.
(package private) java.math.BigDecimal	readUnsignedLong() Reads an unsigned long value from the server response stream.
(package private) int	skip(int skip) Discards bytes from the server response stream.
(package private) void	skipString(int len) Skips a String from the server response stream.
(package private) void	skipToEnd() Consumes the rest of the server response, without parsing it.

Methods inherited from class java.lang.Object

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

Field Detail

socket

private final SharedSocket socket

The shared network socket.

buffer

private byte[] buffer

The Input packet buffer.

bufferPtr

private int bufferPtr

The offset of the next byte to read.

bufferLen

private int bufferLen

The length of current input packet.

streamId

private final int streamId

The unique stream id.

isClosed

private boolean isClosed

True if stream is closed.

byteBuffer

private final byte[] byteBuffer

A shared byte buffer.

charBuffer

private final char[] charBuffer

A shared char buffer.

Constructor Detail

ResponseStream

ResponseStream(SharedSocket socket,
               int streamId,
               int bufferSize)

Constructs a RequestStream object.

Parameters:

socket - the shared socket object to write to

streamId - the unique id for this stream (from ResponseStream)

bufferSize - the initial buffer size

Method Detail

getStreamId

int getStreamId()

Retrieves the unique stream id.

Returns:

the unique stream id as an int

peek

int peek()
   throws java.io.IOException

Retrieves the next input byte without reading forward.

Returns:

the next byte in the input stream as an int

Throws:

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

read

int read()
   throws java.io.IOException

Reads the next input byte from the server response stream.

Returns:

the next byte in the input stream as an int

Throws:

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

read

int read(byte[] b)
   throws java.io.IOException

Reads a byte array from the server response stream.

Parameters:

b - the byte array to read into

Returns:

the number of bytes read as an int

Throws:

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

read

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

Reads a byte array from the server response stream, specifying a start offset and length.

Parameters:

b - the byte array

off - the starting offset in the array

len - the number of bytes to read

Returns:

the number of bytes read as an int

Throws:

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

read

int read(char[] c)
   throws java.io.IOException

Reads a char array from the server response stream.

Parameters:

c - the char array

Returns:

the byte array as a byte[]

Throws:

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

readString

java.lang.String readString(int len)
                      throws java.io.IOException

Reads a String object from the server response stream. If the TDS protocol version is 4.2 or 5.0 decode the string use the default server charset, otherwise use UCS2-LE (Unicode).

Parameters:

len - the length of the string to read in bytes in the case of TDS 4.2/5.0 and in characters for TDS 7.0+ (UCS2-LE encoded strings)

Returns:

the result as a String

Throws:

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

skipString

void skipString(int len)
          throws java.io.IOException

Skips a String from the server response stream. If the TDS protocol version is 4.2 or 5.0 len is the length in bytes, otherwise it's the length in UCS2-LE characters (length in bytes == 2 * len).

Parameters:

len - the length of the string to skip in bytes in the case of TDS 4.2/5.0 and in characters for TDS 7.0+ (UCS2-LE encoded strings)

Throws:

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

readUnicodeString

java.lang.String readUnicodeString(int len)
                             throws java.io.IOException

Reads a UCS2-LE (Unicode) encoded String object from the server response stream.

Parameters:

len - the length of the string to read in characters

Returns:

the result as a String

Throws:

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

readNonUnicodeString

java.lang.String readNonUnicodeString(int len)
                                throws java.io.IOException

Reads a non Unicode String from the server response stream, creating the String from a translated byte array.

Parameters:

len - the length of the string to read in bytes

Returns:

the result as a String

Throws:

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

readNonUnicodeString

java.lang.String readNonUnicodeString(int len,
                                      CharsetInfo charsetInfo)
                                throws java.io.IOException

Reads a String from the server response stream, translating it from a byte array using the specified character set.

Parameters:

len - the length of the string to read in bytes

Returns:

the result as a String

Throws:

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

readString

java.lang.String readString(int len,
                            CharsetInfo info)
                      throws java.io.IOException

Reads a String from the server response stream, creating it from a translated byte array.

Parameters:

len - the length of the string to read in bytes

info - descriptor of the charset to use

Returns:

the result as a String

Throws:

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

readShort

short readShort()
          throws java.io.IOException

Reads a short value from the server response stream.

Returns:

the result as a short

Throws:

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

readInt

int readInt()
      throws java.io.IOException

Reads an int value from the server response stream.

Returns:

the result as a int

Throws:

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

readLong

long readLong()
        throws java.io.IOException

Reads a long value from the server response stream.

Returns:

the result as a long

Throws:

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

readUnsignedLong

java.math.BigDecimal readUnsignedLong()
                                throws java.io.IOException

Reads an unsigned long value from the server response stream.

Returns:

the result as a BigDecimal

Throws:

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

skip

int skip(int skip)
   throws java.io.IOException

Discards bytes from the server response stream.

Parameters:

skip - the number of bytes to discard

Returns:

the number of bytes skipped

Throws:

java.io.IOException

skipToEnd

void skipToEnd()

Consumes the rest of the server response, without parsing it.

Note: Use only in extreme cases, packets will not be parsed and could leave the connection in an inconsistent state.

close

void close()

Closes this response stream. The stream id is unlinked from the underlying shared socket as well.

getTdsVersion

int getTdsVersion()

Retrieves the TDS version number.

Returns:

the TDS version as an int

getServerType

int getServerType()

Retrieves the server type.

Returns:

the server type as an int

getInputStream

java.io.InputStream getInputStream(int len)

Creates a simple InputStream over the server response.

This method can be used to obtain a stream which can be passed to InputStreamReaders to assist in reading multi byte character sets.

Parameters:

len - the number of bytes available in the server response

Returns:

the InputStream built over the server response

getPacket

private void getPacket()
                throws java.io.IOException

Read the next TDS packet from the network.

Throws:

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