com.stc.connector.hl7.framework.llp
Class MLLP

java.lang.Object
  com.stc.connector.hl7.framework.llp.MLLP

Direct Known Subclasses:

MLLPV2

public class MLLP
extends java.lang.Object

This class represents the MLLP structure.

 MLLP (Minimal Lower Layer Protocol):   
 
   [ SOB ][ HL7 Data ][ EOD ][ EOB]
 
 HLLP (Hybrid Lower Layer Protocol):   
 
   [ SOB ][ N | D ][ VER ][ CR ][ HL7 Data ][ LEN ][ BCC ][ EOD ][ EOB ]
 
 where:
 
    SOB: start of block (character)
    EOD: end of data    (character)
    EOB: end of block   (character)
    BCC: block checksum (character)
    CR : Carriage return(character)
    LEN: Length of HL7 Data (starting from SOB to end of HL7 data)
    N  : NAK block
    D  : Data block
    VER: HL7 version :: 21, 22, 23 (i.e., 2.1, 2.2, 2.3, ...)
 
 Assumptions:
 
     LEN : is 5 digit decimal (left zero filled) 
          -- largest value is 99999 bytes
 
     BCC : is 3 digit decimal (left zero filled)
           calculation algorithm is XOR.
          (999 means ignore BCC verification/calculation)
 
 NOTE:
 
     The values of the Start of Block [SOB],  
     End of Data [EOD] and End of Block [EOB], 
     must be UNIQUE.
 
 

The original specification is as follow:

 For HLLP (Hybrid Lower Layer Protocol):
 
 tvvddddcccccxxx
 
 Blocks consist of the following fields. Note that these are LLP 
 fields and are not the same as HL7 message fields.
 
  = Start Block character (1 byte)
      Configurable on a site specific basis. Unless there is a conflict, the
      value should be ASCII , i.e., <0x0B>. This should
      not be confused with the ASCII characters SOH or STX.
 t = Block Type (1 byte)
      'D' = data block
      'N' = NAK block
 vv = Protocol ID (2 bytes)
      The characters '2' '3' for this version
  = Carriage Return (1 byte)
      The ASCII carriage return character, i.e., <0x0D>.
 dddd = Data (variable number of bytes)
      In a data block, this is the data content of the block. The data can
      contain any displayable ASCII characters and the carriage return
      character, . Carriage returns that are not part of the HL7
      message may be inserted as described in "Carriage Return Stuffing."
      In a NAK block, this field contains a 1-byte reason code as follows:
          'C' - character count wrong in previous data block received
          'X' - checksum wrong in previous data block received
          'B' - data too long for input buffer in previous block received
          'G' - Error not covered elsewhere.
 ccccc = Block Size (5 bytes)
      Character count of all characters so far in the data block up to and
      including the last data character. For this version of the protocol this
      is 5 + the size of the dddd field. Note: HL7 message ends with a
       character. This character is considered as part of the data.
 xxx = Checksum (3 bytes)
      Exclusive-OR checksum of all characters in the block up to and
      including the last data character. The checksum is expressed as a
      decimal number in three ASCII digits.
      If the value of this field is 999, the checksum should not be
      computed. Processing will proceed as if it were correct. This feature
      is used for applications where the messages will be translated from
      one character set to another during transmission.
  = End Block character (1 byte)
      Configurable on a site specific basis. Unless there is a conflict, the
      value should be ASCII , i.e., <0x1C>. This should not be
      confused with the ASCII characters ETX or EOT.
  = Carriage Return (1 byte)
      The ASCII carriage return character, i.e., <0x0D>.
 
 
 For MLLP (Minimal Lower Layer Protocol):
 
 dddd
 
  = Start Block character (1 byte)
      ASCII , i.e., <0x0B>. This should not be confused with the ASCII characters
      SOH or STX.
 dddd = Data (variable number of bytes)
      This is the HL7 data content of the block. The data can contain any displayable
      ASCII characters and the carriage return character, .
  = End Block character (1 byte)
      ASCII , i.e., <0x1C>. This should not be confused with the ASCII characters
      ETX or EOT.
  = Carriage Return (1 byte)
      The ASCII carriage return character, i.e., <0x0D>.
 

Version:

cvs revision: $Revision: 1.6 $ Last Modified: $Date: 2005/09/03 06:28:21 $

Author:

Harry Liu

Field Summary

static java.lang.String

version

Constructor Summary

MLLP(HL7LLPInfo hl7LLPInfo)
Constructor for MLLP.

Method Summary

byte[]	constructLLPMessage(byte[] pureMsgBody) Method constructLLPMessage.
byte[]	extractHL7MessageBody(byte[] llpMessage) Method extractHL7MessageBody.

Methods inherited from class java.lang.Object

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

Field Detail

version

public static final java.lang.String version

See Also:

Constant Field Values

Constructor Detail

MLLP

public MLLP(HL7LLPInfo hl7LLPInfo)

Constructor for MLLP.

Parameters:

hl7LLPInfo -

Method Detail

extractHL7MessageBody

public byte[] extractHL7MessageBody(byte[] llpMessage)
                             throws MLLPParsingtException

Method extractHL7MessageBody. It returns the pure hl7 data block.

Parameters:

llpMessage -

Returns:

byte[]

Throws:

MLLPParsingtException

constructLLPMessage

public byte[] constructLLPMessage(byte[] pureMsgBody)
                           throws HL7ApplicationException

Method constructLLPMessage. It returns the whole llp message.

Parameters:

pureMsgBody -

Returns:

byte[]

Throws:

HL7ApplicationException