The msgtransform tool is a useful command line utility that allows you to use the mapping logic in a VMD file to transform messages. For the purposes of this tutorial, you will use msgtransform and the VMD file you examined in the previous step to parse multiple ADT messages.

To use the msgtransform tool:

• Download this sample message file and save it in the directory that you saved the sample VMD file in (for instance, c:\test).

• Open a Command Prompt window, and navigate to the directory in which you have saved the sample VMD file and message file. For example:

C:\>cd test

C:\test>

• Run the msgtransform utility to parse your sample message file. For example, if the VMD file is named msgtransform.vmd and the sample message file is in message.txt, here is an example of what you see when you run msgtransform:

C:\test>msgtransform --table msgtransform.vmd messages.txt output.txt
Message Format: HL7Standard
8 messages
Elapsed time:
8 messages processed in less than a second!

Here, the --table option specifies that you want msgtransform to perform table grammar mapping. The three parameters (all of which are required) specify, in order:

• The name of the VMD file that you want to use to parse messages (in this case, msgtransform.vmd);
• The name of the file containing the messages that you want to parse (here, this is the sample message file, which is assumed to be in messages.txt);
• The name of the output file (output.txt).

For the sample regression test that you are performing in this tutorial, the output file, output.txt, is the baseline file, containing output that you know is correct. In the subsequent steps, you will change your VMD file, and then run msgtransform again to compare its output to the output that you have just generated here.