Verifying Any ACK Message in Chameleon

This example shows you how to verify any ACK message in Chameleon. In this example the ack_verify2.vmd (based on the VMD shipped with Iguana) is used to parse the ACK and ensure that it is a valid ACK HL7 message. When verifying any ACK message, your application should check if the acknowledgment is valid using only the message identity. Since ack_verify2.vmd has "ACK" listed as the message type, this means that your application will expect "ACK" to be the message type of the ACK message from the target machine.

The following code example shows how you would typically verify any ACK message in your client application using the dynamic interface.


	The example below demonstrates the dynamic interface's usage using C++. The syntax will vary slightly when using other programming languages.

Load and instantiate a dynamic engine object at the beginning of your application:

// Create a dynamic engine object.
CHMengine VerifyEngine;
         
// Load the ack_verify2.VMD file.
VerifyEngine.Load("ack_verify2.vmd");

Insert the methods below into the CHMclient class:

void CHMclient::ExtractAckData
(
   const CHMtable& AckTable
)
{
   if (AckTable.CountOfRow() > 0)
   {
      for (int SubTableIndex = 0;
          SubTableIndex < AckTable.CountOfSubTable();
          SubTableIndex++)
      {
         CHMtable* SubTable = AckTable.SubTable(0, SubTableIndex);

         if (CHMstring(SubTable->TableName()) == "MSA")
         {
            for (int RowIndex = 0;
                RowIndex < SubTable->CountOfRow();
                RowIndex++)
            {
               for (int ColumnIndex = 0;
                   ColumnIndex < SubTable->CountOfColumn();
                   ColumnIndex++)
               {
                  if (CHMstring(SubTable->ColumnName(ColumnIndex)) == "AcknowledgmentCode")
                  {
                     cout << "Acknowledgment Code: " << SubTable->GetString(RowIndex, ColumnIndex) << endl;
                  }
                  else if (CHMstring(SubTable->ColumnName(ColumnIndex)) == "MessageControlID")
                  {
                     cout << "Message Control ID: " << SubTable->GetString(RowIndex, ColumnIndex) << endl;
                  }
                  else if (CHMstring(SubTable->ColumnName(ColumnIndex)) == "ErrorText")
                  {
                     cout << "Error Text: " << SubTable->GetString(RowIndex, ColumnIndex) << endl;
                  }
               }
            }
         }
      }
   }
}

// This event fires when a message is received.  Usually the message received 
// is an ACK message.  If, however, you are implementing a lab query interface 
// it might be a lab result message.  For this example we are assuming it is an ACK message and
// just printing it.
void CHMclient::OnMessageReceived
(
   const char* Message 
)
{
   cout << "Received a message." << endl;

   try
   {
      // Instantiate a table object.
      CHMtable AckTable;
      size_t MessageIndex;

      // Parse the message.
      VerifyEngine.ParseMessageDynamically(Message, AckTable, MessageIndex);

      CHMstring MessageString = MakeMessagePrintable(Message, NEWLINE, MAX_MESSAGE_LENGTH);

      switch (MessageIndex)
      {
      case 0:
         cout << "ACK:" << endl << MessageString.c_str() << endl;

         // Extract information from the AckTable.
         ExtractAckData(AckTable);
         break;

      case 1:
         cout << "NOT ACK:" << endl << MessageString.c_str() << endl;
         break;
      }
   }
   catch (CHMerror& Error)
   {
      cout << "Parsing error: " << Error.Description();
   }

   RunMainMenu();
}

This is the resulting output:

Sending message:
MSH|^~\&||.|||199908180016||ADT^A04|020995477102C887A7A06DEDECF99305|P|2.1
PID|1||000395122||LEVERKUHN^ADRIAN^C^^^||19880517180606|M|^^^^^||6 66TH AVE NE^^WEIMAR^DL^98052||(157)983-3296|||S||12354768|87654321
NK1|1|TALLIS^THOMAS^C|GRANDFATHER|12914 SPEM ST^^ALIUM^IN^98052|(157)883-6176
NK1|2|WEBERN^ANTON|SON|12 STRASSE MUSIK^^VIENNA^AUS^11212|(123)456-7890
PV1|1|E|EMG-W^^|1||||||||||ER||||ER||H|||||||||||||||||||OVL||REG|||199908180015
GT1|1||SMITH^JAMES^M||12914 164TH AVE NE^^RICHMOND^ON^98052|(157)883-6176|||||F|535-52-9776||||WEISS JENSON|.^^WELLINGTON^ON^.|(206)340-9577 
IN1|1|PRE2|001|LIFE PRUDENT BUYER|PO BOX 23523^WELLINGTON^ON^98111|||19601||||||||THOMAS^JAMES^M|F|||||||||||||||||||ZKA535529776

Received a message.
ACK:
MSH|^~\&|||||||ACK|A020995477102C887A7A06DEDECF99305|P||
MSA|AA|020995477102C887A7A06DEDECF99305|

Acknowledgment Code: AA
Message Control ID: 020995477102C887A7A06DEDECF99305
Error Text:

Since the resulting ACK code is a positive ACK, there will be no error text.

iNTERFACEWARE™ Inc.

Verifying Any ACK Message in Chameleon