WSO2 Enterprise Integrator iterate and aggregate, issue with aggregation

Question

I want to perform parallel API calls in iterate mediator then to group the responses using the aggregate mediator. The format is JSON. I am using this code:

 [...code in iterate]
<script language="js">var c = mc.getProperty("account");
                                  
                                    print("Value : "+ c );
                                    mc.setProperty("concatValue", c);
                                    mc.setPayloadJSON({"result":{"account" : c}});</script>
                                    
<log>
                 <property expression="json-eval($)" name="JSON-Payload in sequence"/>
              </log>
              

             </sequence>
       

        </target>
     </iterate>
        
    <property name="Aggregated_Responses" scope="default" value = "{}"/>
        
    <aggregate id="it1">
        <completeCondition>
          <messageCount max="-1" min="-1"/>
        </completeCondition>
        <onComplete expression="json-eval($)" enclosingElementProperty="Aggregated_Responses">
             <log>
                 <property expression="json-eval($)" name="JSON-Payload in oncomplete"/>
              </log>
        </onComplete>
   </aggregate>
  <loopback/>
</sequence>

The aggregation is not working, if i add loopback isnide the on complete, it will return one json and the second one will print a message in the logs saying that the response was already sent. Can someone help me solve this issue? And an additional question: do the work inside the iterate is usually done in parallel or in series?

Answer 1

Final working solution with some explanation:

<payloadFactory media-type="json">
<format>
            {               
                "payloadss": [{
"account":"99999999999"
                    
                },{
"account":"6666666666"
                    
                }]
            }
            </format>
<args/>
 </payloadFactory>
<iterate attachPath="json-eval($.payloadss)" expression="json-eval($.payloadss)" 
 id="iterate-over" preservePayload="true" continueParent="false">
<target>
    <sequence>
        <property expression="json-eval($.payloadss.account)" name="accounte" scope="default" type="STRING"/>
        <call-template target="call_template_a">
            <with-param name="url" value="/getaccount"/>
            <with-param name="method_type" value="get"/>
        </call-template>
            [.. apply error check etc .. ] 
   
        </sequence>
</target>
</iterate>
        [ use same id as the iterate otherwise it wont work ]
         <property name="Aggregated_Responses" scope="default">
            <jsonObject/>
         </property>
     <aggregate description="iterate-over" id="iterate-over">
   <completeCondition timeout="120">
     <messageCount max="-1" min="-1"/>
   </completeCondition>

   [ use expression like this otherwise it wont work, you can even add at the end / 
      your field name if needed ]

<onComplete xmlns:ns="http://org.apache.synapse/xsd" expression="$body/*[1]" 
   enclosingElementProperty="Aggregated_Responses">

  [ here the json will be as payload, optionnally you can have a script mediator 
  to map the value and change in their names, otherwise you can just return the 
      result and it
     will be aggregated together]

  <property expression="json-eval($)" name="bbbb"/>
    <script language="js"><![CDATA[
  var dataFull = JSON.parse(mc.getProperty('bbbb')); 
            var responseList = [];
        var newJson = JSON.parse("{}");

            for (i = 0; i < dataFull.length; i++) {
       
                item = dataFull[i];
                newJson.newAccountNumber = item.accountNumber;
                        responseList.push(newJson);
            }
            
            mc.setProperty("responseList", JSON.stringify(responseList));
            ]]></script>
    <payloadFactory media-type="json">
        <format>
                            {
                                    "data": $2
                            }

                        </format>
        <args>
            <arg evaluator="xml" expression="get-property('responseList')"/>
        </args>
    </payloadFactory>

[ the send should be at this level, the code just after will not be executed] 
    <send/>
</onComplete>