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Using Javascript Functions in Siddhi Applications

Purpose:

This sample demonstrate how javascript functions can be used in Siddhi Applications.

Prerequisites:

  1. Save this sample.

Executing the Sample:

  1. Start the Siddhi application by clicking on 'Run'.
  2. If the Siddhi application starts successfully, the following messages would be shown on the console.
    * Script-js-sample.siddhi - Started Successfully!

Testing the Sample:

  1. To open event simulator by clicking on the second icon or press Ctrl+Shift+I.
  2. In the Single Simulation tab of the panel, select values as follows:
    • Siddhi App Name: Script-js-sample
    • Stream Name: SweetProductiontream
  3. In the name field and amount fields, enter 'toffee', '45.25' respectively and then click Send to send the event.
  4. Send some more events.

Viewing the Results:

See the output on the console. Description of the raw material with the passed details are shown in the logger.You will get the output as follows:

[2017-12-20_14-26-03_120] INFO {io.siddhi.core.stream.output.sink.LogSink} - Script-js-sample : logStream : Event{timestamp=1513760163112, data=[toffee, 45.25, There are 45.25kg of toffee in the store], isExpired=false}

Notes: If you need to edit this application while it is running, then Save -> Start.

@App:name('Script-js-sample')
@App:Description('Demonstrate how javascript functions can be used in Siddhi Applications.')


define stream sweetProductionStream (name string, amount double);

@sink(type='log')
define stream logStream (name string, amount double, itemDescription string);

define function detailedMaterial[JavaScript] return string {
     var name = data[0];
     var amount = data[1];
     var res = "There are "+amount+"kg of "+name+ " in the store";
     return res;
};

from sweetProductionStream select name , amount, detailedMaterial(name,amount) as itemDescription
insert into detailedProductionstream;

from detailedProductionstream
select *
insert into logStream;
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