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iNTERFACEWARE Products Manual > Installing and Using Chameleon > Troubleshooting > Distinguishing Between Null, Zero, Empty and Invalid in Fields
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Distinguishing Between Null, Zero, Empty and Invalid in Fields

In Chameleon versions prior to 4.0, there was a problem in which the difference between 0 and Null in an HL7 message could not be distinguished in Java, Delphi and C#.

For example, when using the method, Table.getInteger(col, row), you would get a zero if the message did not have a value in the corresponding field in Java after parsing an incoming HL7 message.

To fix this issue for the different parser engines, two functions were added to Chameleon. The table below describes the two functions:

Parser EngineFunction AddedDescription
3.211 to 4.5IsNull This function was added to Chameleon 4.0 to help distinguish between Null and Zero.
5.0 and later GetState This function was added to Chameleon 5.0 to help distinguish between Null, Zero, Empty and Invalid.

 

Note that the IsNull function is now deprecated in Parser Versions 5.0 and later (Options > Misc) and has been replaced with the GetState function. However, for backward compatibility reasons the IsNull function will still be available and supported for all previous parser versions.

IsNull vs. GetState

  • IsNull - If you are still using the 4.5 parser engine, it is recommended that you continue to use the IsNull function in your application since the GetState function may produce unwanted results.
  • GetState - If you are using the 5.0 parser engine, it is recommended that you use the new GetState function.

Usage examples are provided for each function and each supported language below: