Inserting and Accessing Data in a Map

Purpose

This function creates a map and added values and checks whether values are available

Prerequisites

• Save this sample. If there is no syntax error, the following messages would be shown on the console
  • Siddhi App MapExtensionSample successfully deployed.

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
   • MapExtensionSample.siddhi - Started Successfully!

Testing the Sample

You can publish data event to the file, through event simulator

1. 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 : MapExtensionSample
   • Stream Name : SweetProductionStream
3. Enter following values in the fields and send
   • name: chocolate cake
   • amount: 50.50

Viewing the Results

Messages similar to the following would be shown on the console.

INFO {io.siddhi.core.query.processor.stream.LogStreamProcessor} - MapExtensionSample: Event: , StreamEvent{ timestamp=1513384974698, beforeWindowData=null, onAfterWindowData=null, outputData=[true, false], type=CURRENT, next=null}

@app:name("MapExtensionSample")

@app:description('Insert values into a map and access')

@sink(type='log')
define stream CheckedMapStream(isMap1 bool, isMap2 bool);

define stream SweetProductionStream (name string, amount double);

@info(name = 'query1')
from SweetProductionStream
select name, amount, map:create() as tmpMap
insert into tmpStream;

@info(name = 'query2')
from tmpStream  select name, amount, map:put(tmpMap,name,amount) as map1
insert into outputStream;

@info(name = 'query3')
from outputStream
select map:isMap(map1) as isMap1, map:isMap(name) as isMap2
insert into CheckedMapStream;