Can a StreamBase Java custom function return a Java object to EventFlow

[paolo tarpanelli]

Hello,

how can i return from a custom java function a class object from an external jar file.

For example: let us suppose I have a Map operator containing my custom java function (fun) whic uses a class, from an external jar file, and returns an object x and I would liket that my fun return the object x such that the output of the Map operator is the object x. How can i do it:

What type of return I need to specify in the .sbconf when I ama going to define the custom function

Thank you

best regards

Paolo

[Steve Barber]

Hi Paolo,

You can only return a Java data type that maps to a StreamBase data type and there is no defined mapping from java.lang.Object (POJO) directly to any StreamBase data type. Similarly theres no direct way for a POJO to traverse a StreamBase stream.

You could have your custom function get the values of fields in your POJO and set corresponding fields in a com.streambase.sb.Tuple and have the function return that. To return a tuple type from a custom Java plugin function you will need to implement a custom function resolver for the plugin function.

Another possibility is to serialize your POJO into a blob, but thats not very convenient in practice.

[paolo tarpanelli]

Clear.

 

Thanks

[Steve Barber]

Here is a link to a Support Knowledge Base article that gives an example of how to define a custom Java plugin function that returns a StreamBase tuple data type, along with a corresponding custom function resolver: https://supportapps.tibco.com/ka/article/457/000028457.htm