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SUMMARY: JavaDoc of org.apache.derby.impl.drda.DDMWriter JAVADOC | Sourc code of org.apache.derby.impl.drda.DDMWriter SOURCE | Download org.apache.derby.impl.drda.DDMWriter DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD

org.apache.derby.impl.drda
Class DDMWriter  view DDMWriter download DDMWriter.java

java.lang.Object
  extended byorg.apache.derby.impl.drda.DDMWriter
class DDMWriter
extends java.lang.Object

The DDMWriter is used to write DRDA protocol. The DRDA Protocol is described in the DDMReader class. For more details, see DRDA Volume 3 (Distributed Data Management(DDM) Architecture (DDS definition)

Field Summary
private  DRDAConnThread agent
           
private  byte[] bytes
           
private  CcsidManager ccsidManager
           
private  int correlationID
           
private static int DEFAULT_BUFFER_SIZE
           
private  int dssLengthLocation
           
private  DssTrace dssTrace
           
private  boolean isContinuationDss
           
private  boolean isDRDAProtocol
           
private  int lastDSSBeforeMark
           
private  int[] markStack
           
private static int MAX_MARKS_NESTING
           
private  int nextCorrelationID
           
private  int offset
           
private  int prevHdrLocation
           
private  byte previousChainByte
           
private  int previousCorrId
           
private  int top
           
(package private) static java.math.BigDecimal ZERO
           
 
Constructor Summary
(package private) DDMWriter(CcsidManager ccsidManager, DRDAConnThread agent, DssTrace dssTrace)
           
(package private) DDMWriter(int minSize, CcsidManager ccsidManager, DRDAConnThread agent, DssTrace dssTrace)
           
 
Method Summary
private  void beginDss(boolean chainedToNextStructure, int dssType)
          Begins a DSS stream (for writing LOB data).
private  void beginDss(int dssType, boolean ensureLen)
          Write DSS header DSS Header format is 2 bytes - length 1 byte - 'D0' - indicates DDM data 1 byte - DSS format |---|---------|----------| | 0 | flags | type | |---|---------|----------| | 0 | 1 2 3 | 4 5 6 7 | |---|---------|----------| bit 0 - '0' bit 1 - '0' - unchained, '1' - chained bit 2 - '0' - do not continue on error, '1' - continue on error bit 3 - '0' - next DSS has different correlator, '1' - next DSS has same correlator type - 1 - Request DSS - 2 - Reply DSS - 3 - Object DSS - 4 - Communications DSS - 5 - Request DSS where no reply is expected
private  int bigDecimalToPackedDecimalBytes(java.math.BigDecimal b, int precision, int scale)
          Write a Java java.math.BigDecimal to packed decimal bytes.
private  int calculateExtendedLengthByteCount(long ddmSize)
          Calculate extended length byte count which follows the DSS header for extended DDM.
protected  void clearBuffer()
          Clear the entire send buffer
protected  void clearDdm()
          Erase all writes for the current ddm and reset the top
protected  void clearDSSesBackToMark(int mark)
          Does a logical "clear" of everything written to the buffer after the received mark.
protected  byte[] copyDataToEnd(int start)
          Copy Data to End Create a buffer and copy from the position given to the end of data
protected  void createDssObject()
          Create DSS data object
protected  void createDssReply()
          Create DSS reply object
protected  void createDssRequest()
          Create DSS request object NOTE: This is _ONLY_ used for testing the protocol (via the TestProto.java file in this package)! We should never create a DSS request in normal DRDA processing (we should only create DSS replies and DSS objects).
protected  boolean doesRequestContainData()
           
protected  void endDdm()
          End the current DDM
protected  void endDdmAndDss()
          End final DDM and DSS header by writing the length in the length location
protected  void endDss()
          End DSS header by writing the length in the length location and setting the chain bit.
private  void endDss(boolean finalizeLength)
          End DSS header by writing the length in the length location and setting the chain bit.
protected  void endDss(byte chainByte)
          End DSS header by writing the length in the length location and setting the chain bit.
private  void ensureLength(int length)
          Ensure that there is space in the buffer
protected  void finalizeChain(byte currChainByte, java.io.OutputStream socketOutputStream)
          Finalize the current DSS chain and send it if needed.
private  void finalizeDssLength()
          Finish a DSS Layer A object.
protected  void flush()
          Flush buffer to outputstream
protected  void flush(java.io.OutputStream socketOutputStream)
          Flush buffer to specified stream
protected  int flushScalarStreamSegment(int leftToRead, int bytesToRead)
           
private  int getCorrelationID()
          Looks at chaining info for previous DSS written, and use that to figure out what the correlation id for the current DSS should be.
protected  int getOffset()
          Get offset
private  void markDssAsContinued(boolean forLob)
          Mark the DSS that we're currently writing as a continued DSS, which is done by setting the high-order bit to "1", per DDM spec.
protected  int markDSSClearPoint()
          Takes note of the location of the most recently completed DSS in the buffer, and then returns the current offset.
private static int min(int i, int j)
           
protected  void padBytes(byte val, int length)
          Write pad bytes using spaceChar
protected  void padScalarStreamForError(int leftToRead, int bytesToRead)
           
protected  int prepScalarStream(boolean chainedWithSameCorrelator, int codePoint, boolean writeNullByte, int leftToRead)
           
protected  void reset(DssTrace dssTrace)
          reset values for sending next message
protected  void resetChainState()
          Reset any chaining state that needs to be reset at time of the send
private  void sendBytes(java.io.OutputStream socketOutputStream)
           
protected  void setCMDProtocol()
          set protocol to CMD protocol
protected  void setOffset(int value)
          Set offset
protected  void startDdm(int codePoint)
          Mark the location of the length bytes for the collection so they can be updated later
protected  void startDdm(int length, int codePoint)
          Write length and codepoint
protected  java.lang.String toDebugString(java.lang.String indent)
           
protected  void writeBigDecimal(java.math.BigDecimal v, int precision, int scale)
          Write big decimal to buffer
protected  void writeBoolean(boolean v)
          Write platform boolean
protected  void writeByte(int value)
          Write byte
protected  void writeBytes(byte[] buf)
          Write byte array
protected  void writeBytes(byte[] buf, int length)
          Write byte array
protected  void writeBytes(byte[] buf, int start, int length)
          Write byte array
(package private)  void writeCodePoint4Bytes(int codePoint, int value)
          Write code point and 4 bytes
protected  void writeDouble(double v)
          Write platform double
protected  void writeExtendedLength(long size)
           
private  void writeExtendedLengthBytes(int extendedLengthByteCount, long length)
           
protected  void writeFloat(float v)
          Write platform float
protected  void writeInt(int v)
          Write platform int
protected  void writeLDBytes(byte[] buf)
           
protected  void writeLDBytes(byte[] buf, int index)
           
protected  void writeLDString(java.lang.String s)
          Write length delimited string
protected  void writeLDString(java.lang.String s, int index)
          Write length delimited string
(package private)  void writeLengthCodePoint(int length, int codePoint)
           
protected  void writeLong(long v)
          Write platform long
protected  void writeNetworkInt(int value)
          Write network int
protected  void writeNetworkShort(int value)
          Write network short
(package private)  void writeScalar1Byte(int codePoint, int value)
          Write scalar 1 byte object includes length, codepoint and value
protected  void writeScalar2Bytes(int value)
           
protected  void writeScalar2Bytes(int codePoint, int value)
          Write scalar 2 byte object includes length, codepoint and value
protected  void writeScalarBytes(int codePoint, byte[] buf)
          Write scalar byte array object includes length, codepoint and value
protected  void writeScalarBytes(int codePoint, byte[] buf, int length)
          Write scalar byte array object includes length, codepoint and value
protected  void writeScalarBytes(int codePoint, byte[] buf, int start, int length)
          Write scalar byte array object includes length, codepoint and value
protected  void writeScalarHeader(int codePoint, int dataLength)
          Write scalar object header includes length and codepoint
protected  void writeScalarPaddedBytes(byte[] buf, int paddedLength, byte padByte)
          Write padded scalar byte array object value
protected  void writeScalarPaddedBytes(int codePoint, byte[] buf, int paddedLength, byte padByte)
          Write padded scalar byte array object includes length, codepoint and value
(package private)  void writeScalarPaddedString(int codePoint, java.lang.String string, int paddedLength)
          Write padded scalar string object includes length, codepoint and value the string is converted into the appropriate codeset (EBCDIC)
protected  void writeScalarPaddedString(java.lang.String string, int paddedLength)
          Write padded scalar string object value the string is converted into the appropriate codeset (EBCDIC)
protected  int writeScalarStream(boolean chainedWithSameCorrelator, int codePoint, int length, java.io.InputStream in, boolean writeNullByte)
           
(package private)  void writeScalarString(int codePoint, java.lang.String string)
          Write scalar string object includes length, codepoint and value the string is converted into the appropriate codeset (EBCDIC)
protected  void writeShort(boolean b)
          Write boolean as short
protected  void writeShort(int v)
          Write platform short
protected  void writeString(java.lang.String s)
          Write string with default encoding
protected  void writeString(java.lang.String s, int length)
          Write string with default encoding and specified length
static java.lang.String zeroPadString(java.lang.String s, int precision)
          Prepend zeros to numeric string
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

MAX_MARKS_NESTING

private static final int MAX_MARKS_NESTING
See Also:
Constant Field Values

DEFAULT_BUFFER_SIZE

private static final int DEFAULT_BUFFER_SIZE
See Also:
Constant Field Values

ZERO

static final java.math.BigDecimal ZERO

bytes

private byte[] bytes

offset

private int offset

markStack

private int[] markStack

top

private int top

ccsidManager

private CcsidManager ccsidManager

agent

private DRDAConnThread agent

dssLengthLocation

private int dssLengthLocation

correlationID

private int correlationID

nextCorrelationID

private int nextCorrelationID

isDRDAProtocol

private boolean isDRDAProtocol

dssTrace

private DssTrace dssTrace

prevHdrLocation

private int prevHdrLocation

previousCorrId

private int previousCorrId

previousChainByte

private byte previousChainByte

isContinuationDss

private boolean isContinuationDss

lastDSSBeforeMark

private int lastDSSBeforeMark
Constructor Detail

DDMWriter

DDMWriter(int minSize,
          CcsidManager ccsidManager,
          DRDAConnThread agent,
          DssTrace dssTrace)

DDMWriter

DDMWriter(CcsidManager ccsidManager,
          DRDAConnThread agent,
          DssTrace dssTrace)
Method Detail

reset

protected void reset(DssTrace dssTrace)
reset values for sending next message

setCMDProtocol

protected void setCMDProtocol()
set protocol to CMD protocol

createDssReply

protected void createDssReply()
Create DSS reply object

createDssRequest

protected void createDssRequest()
Create DSS request object NOTE: This is _ONLY_ used for testing the protocol (via the TestProto.java file in this package)! We should never create a DSS request in normal DRDA processing (we should only create DSS replies and DSS objects).

createDssObject

protected void createDssObject()
Create DSS data object

markDssAsContinued

private void markDssAsContinued(boolean forLob)
Mark the DSS that we're currently writing as a continued DSS, which is done by setting the high-order bit to "1", per DDM spec. This means: 1. One or more continuation DSSes will immediately follow the current (continued) DSS. 2. All continuation DSSes will have a 2-byte continuation header, followed by data; in other words, chaining state, correlation id, dss format info, and code point will NOT be included. All of that info is present ONLY in the FIRST DSS in the list of continued DSSes. NOTE: A DSS can be a "continuation" DSS _and_ a "continued" DSS at the same time. However, the FIRST DSS to be continued canNOT be a continuation DSS.

endDss

protected void endDss(byte chainByte)
End DSS header by writing the length in the length location and setting the chain bit. Unlike the other two endDss methods, this one overrides the default chaining byte (which is set in beginDss) with the chaining byte that is passed in. NOTE: This method is only used in association with createDssRequest, and thus is for TESTING purposes only (via TestProto.java). No calls should be made to this method in normal DRDA processing (because for normal processing, chaining must be determined automatically based on DSS requests).

endDss

protected void endDss()
End DSS header by writing the length in the length location and setting the chain bit.

endDss

private void endDss(boolean finalizeLength)
End DSS header by writing the length in the length location and setting the chain bit.

endDdmAndDss

protected void endDdmAndDss()
End final DDM and DSS header by writing the length in the length location

copyDataToEnd

protected byte[] copyDataToEnd(int start)
Copy Data to End Create a buffer and copy from the position given to the end of data

startDdm

protected void startDdm(int codePoint)
Mark the location of the length bytes for the collection so they can be updated later

clearDdm

protected void clearDdm()
Erase all writes for the current ddm and reset the top

clearBuffer

protected void clearBuffer()
Clear the entire send buffer

endDdm

protected void endDdm()
End the current DDM

getOffset

protected int getOffset()
Get offset

setOffset

protected void setOffset(int value)
Set offset

writeByte

protected void writeByte(int value)
Write byte

writeNetworkShort

protected void writeNetworkShort(int value)
Write network short

writeNetworkInt

protected void writeNetworkInt(int value)
Write network int

writeBytes

protected void writeBytes(byte[] buf,
                          int length)
Write byte array

writeBytes

protected void writeBytes(byte[] buf,
                          int start,
                          int length)
Write byte array

writeBytes

protected void writeBytes(byte[] buf)
Write byte array

writeLDBytes

protected void writeLDBytes(byte[] buf)

writeLDBytes

protected void writeLDBytes(byte[] buf,
                            int index)

writeCodePoint4Bytes

void writeCodePoint4Bytes(int codePoint,
                          int value)
Write code point and 4 bytes

writeScalar1Byte

void writeScalar1Byte(int codePoint,
                      int value)
Write scalar 1 byte object includes length, codepoint and value

writeScalar2Bytes

protected void writeScalar2Bytes(int codePoint,
                                 int value)
Write scalar 2 byte object includes length, codepoint and value

writeScalar2Bytes

protected void writeScalar2Bytes(int value)

startDdm

protected void startDdm(int length,
                        int codePoint)
Write length and codepoint

writeScalarBytes

protected void writeScalarBytes(int codePoint,
                                byte[] buf,
                                int length)
Write scalar byte array object includes length, codepoint and value

writeScalarStream

protected int writeScalarStream(boolean chainedWithSameCorrelator,
                                int codePoint,
                                int length,
                                java.io.InputStream in,
                                boolean writeNullByte)
                         throws DRDAProtocolException

beginDss

private void beginDss(boolean chainedToNextStructure,
                      int dssType)
Begins a DSS stream (for writing LOB data).

prepScalarStream

protected int prepScalarStream(boolean chainedWithSameCorrelator,
                               int codePoint,
                               boolean writeNullByte,
                               int leftToRead)
                        throws DRDAProtocolException

doesRequestContainData

protected boolean doesRequestContainData()

flushScalarStreamSegment

protected int flushScalarStreamSegment(int leftToRead,
                                       int bytesToRead)
                                throws DRDAProtocolException

padScalarStreamForError

protected void padScalarStreamForError(int leftToRead,
                                       int bytesToRead)
                                throws DRDAProtocolException

writeExtendedLengthBytes

private void writeExtendedLengthBytes(int extendedLengthByteCount,
                                      long length)

writeLengthCodePoint

void writeLengthCodePoint(int length,
                          int codePoint)

writeScalarHeader

protected void writeScalarHeader(int codePoint,
                                 int dataLength)
Write scalar object header includes length and codepoint

writeScalarString

void writeScalarString(int codePoint,
                       java.lang.String string)
Write scalar string object includes length, codepoint and value the string is converted into the appropriate codeset (EBCDIC)

writeScalarPaddedString

void writeScalarPaddedString(int codePoint,
                             java.lang.String string,
                             int paddedLength)
Write padded scalar string object includes length, codepoint and value the string is converted into the appropriate codeset (EBCDIC)

writeScalarPaddedString

protected void writeScalarPaddedString(java.lang.String string,
                                       int paddedLength)
Write padded scalar string object value the string is converted into the appropriate codeset (EBCDIC)

writeScalarPaddedBytes

protected void writeScalarPaddedBytes(int codePoint,
                                      byte[] buf,
                                      int paddedLength,
                                      byte padByte)
Write padded scalar byte array object includes length, codepoint and value

writeScalarPaddedBytes

protected void writeScalarPaddedBytes(byte[] buf,
                                      int paddedLength,
                                      byte padByte)
Write padded scalar byte array object value

writeScalarBytes

protected void writeScalarBytes(int codePoint,
                                byte[] buf)
Write scalar byte array object includes length, codepoint and value

writeScalarBytes

protected void writeScalarBytes(int codePoint,
                                byte[] buf,
                                int start,
                                int length)
Write scalar byte array object includes length, codepoint and value

writeShort

protected void writeShort(int v)
Write platform short

writeShort

protected void writeShort(boolean b)
Write boolean as short

writeInt

protected void writeInt(int v)
Write platform int

writeLong

protected void writeLong(long v)
Write platform long

writeFloat

protected void writeFloat(float v)
Write platform float

writeDouble

protected void writeDouble(double v)
Write platform double

writeBigDecimal

protected void writeBigDecimal(java.math.BigDecimal v,
                               int precision,
                               int scale)
                        throws java.sql.SQLException
Write big decimal to buffer

writeBoolean

protected void writeBoolean(boolean v)
Write platform boolean

writeLDString

protected void writeLDString(java.lang.String s)
                      throws DRDAProtocolException
Write length delimited string

writeLDString

protected void writeLDString(java.lang.String s,
                             int index)
                      throws DRDAProtocolException
Write length delimited string

writeString

protected void writeString(java.lang.String s)
                    throws DRDAProtocolException
Write string with default encoding

writeString

protected void writeString(java.lang.String s,
                           int length)
                    throws DRDAProtocolException
Write string with default encoding and specified length

padBytes

protected void padBytes(byte val,
                        int length)
Write pad bytes using spaceChar

flush

protected void flush()
              throws java.io.IOException
Flush buffer to outputstream

flush

protected void flush(java.io.OutputStream socketOutputStream)
              throws java.io.IOException
Flush buffer to specified stream

beginDss

private void beginDss(int dssType,
                      boolean ensureLen)
Write DSS header DSS Header format is 2 bytes - length 1 byte - 'D0' - indicates DDM data 1 byte - DSS format |---|---------|----------| | 0 | flags | type | |---|---------|----------| | 0 | 1 2 3 | 4 5 6 7 | |---|---------|----------| bit 0 - '0' bit 1 - '0' - unchained, '1' - chained bit 2 - '0' - do not continue on error, '1' - continue on error bit 3 - '0' - next DSS has different correlator, '1' - next DSS has same correlator type - 1 - Request DSS - 2 - Reply DSS - 3 - Object DSS - 4 - Communications DSS - 5 - Request DSS where no reply is expected

finalizeDssLength

private void finalizeDssLength()
Finish a DSS Layer A object. The length of dss object will be calculated based on the difference between the start of the dss, saved on the beginDss call, and the current offset into the buffer which marks the end of the data. In the event the length requires the use of continuation Dss headers, one for each 32k chunk of data, the data will be shifted and the continuation headers will be inserted with the correct values as needed.

writeExtendedLength

protected void writeExtendedLength(long size)

calculateExtendedLengthByteCount

private int calculateExtendedLengthByteCount(long ddmSize)
Calculate extended length byte count which follows the DSS header for extended DDM.

ensureLength

private void ensureLength(int length)
Ensure that there is space in the buffer

bigDecimalToPackedDecimalBytes

private int bigDecimalToPackedDecimalBytes(java.math.BigDecimal b,
                                           int precision,
                                           int scale)
                                    throws java.sql.SQLException
Write a Java java.math.BigDecimal to packed decimal bytes.

zeroPadString

public static java.lang.String zeroPadString(java.lang.String s,
                                             int precision)
Prepend zeros to numeric string

sendBytes

private void sendBytes(java.io.OutputStream socketOutputStream)
                throws java.io.IOException

min

private static int min(int i,
                       int j)

toDebugString

protected java.lang.String toDebugString(java.lang.String indent)

resetChainState

protected void resetChainState()
Reset any chaining state that needs to be reset at time of the send

getCorrelationID

private int getCorrelationID()
Looks at chaining info for previous DSS written, and use that to figure out what the correlation id for the current DSS should be. Return that correlation id.

finalizeChain

protected void finalizeChain(byte currChainByte,
                             java.io.OutputStream socketOutputStream)
                      throws DRDAProtocolException
Finalize the current DSS chain and send it if needed. Updates the chaining state of the most recently-written- to-buffer DSS to correspond to the most recently-read- from-client request. If that chaining state indicates we've reached the end of a chain, then we go ahead and send the buffer across the wire.

markDSSClearPoint

protected int markDSSClearPoint()
Takes note of the location of the most recently completed DSS in the buffer, and then returns the current offset. This method is used in conjunction with "clearDSSesBackToMark" to allow for DRDAConnThread to "back-out" DSSes in the event of errors.

clearDSSesBackToMark

protected void clearDSSesBackToMark(int mark)
Does a logical "clear" of everything written to the buffer after the received mark. It's assumed that this method will be used in error cases when we've started writing one or more DSSes, but then hit an error and need to back out. After backing out, we'll always need to write _something_ back to the client to indicate an error (typically, we just write an SQLCARD) but what exactly gets written is handled in DRDAConnThread. Here, we just do the necessary prep so that whatever comes next will succeed.

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SUMMARY: JavaDoc of org.apache.derby.impl.drda.DDMWriter JAVADOC | Sourc code of org.apache.derby.impl.drda.DDMWriter SOURCE | Download org.apache.derby.impl.drda.DDMWriter DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD