Time-Based Aggregator Example | MuleSoft Documentation
# Time-Based Aggregator Example
The Aggregators module **Time based aggregator** scope enables you to aggregate elements within a predefined time limit. The following example shows how to configure this scope to aggregate HTTP request calls within `5` seconds. The application uses DataWeave to set the payload of each call with a random ID number. When the aggregation reaches `5` seconds, an **Aggregator listener** source gets the list of elements and the application logs all the aggregated random ID numbers.
Figure 1. Time-Based Aggregator Flow Example
To test this example in your own environment, you must create the Mule application and test it with curl commands.
## Create the Mule Application
To create the Mule flow in Anypoint Studio:
  1. In **Mule Palette** , select **HTTP Listener** and drag it onto the canvas. The source initiates the flow by listening for incoming HTTP message attributes.
  2. In **Connector configuration** , select **HTTP_Listener_config**.
  3. Set **Path** to `/test`.
  4. Drag a **Transform message** component to the right of **Listener**.
  5. In the DataSense preview window of the **Transform message** component, add the following DataWeave expression, which sets to each HTTP request payload a `Source Name` as `"time-based"` and a `Source ID` as `random() as String`:
```
%dw 2.0
output application/json
---
{
  "Source Name": "time-based",
  "Source ID": (random() as String)
}
```

  6. Drag the **Time based aggregator** scope to the right of **Transform message**.
  7. Set **Name** to `timeBasedAggregator`.
  8. Set **Period** to `5`.
  9. Set **Period unit** to `SECONDS(Default)`.
  10. Set **Content** to `payload`, which is the expression that defines what to aggregate; in this case, the transformed HTTP requests.
  11. Drag a **Logger** component into the **Incremental aggregation** route.
  12. In the **Logger** configuration screen, set **Message** to `Doing incremental step.`
  13. Drag an **Aggregator listener** source below the first flow. This source listens to the previous defined time-based aggregator. Once the aggregator releases its elements, the listener is executed.
  14. Set **Aggregator name** to `timeBasedAggregator`.
  15. Drag a **Logger** component to the right of **Aggregator listener**
  16. Set **Message** to `Aggregation complete`.
  17. Drag another **Logger** component to the right of the previous added **Logger** component.
  18. Set **Message** to the following expression, which returns all the aggregated elements:
```
output application/json
---
payload
```

  19. Save the project.
  20. In **Package Explorer** , click **Run > Run As > Mule Application**.
  21. Test the app by sending the following curl command twice within `5` seconds: `curl -X POST http://localhost:8086/test` This generates two HTTP requests for the **Time based aggregator** to process.
  22. Navigate to the **Console** view to read the logger message:


```
INFO 2021-06-09 12:02:04,203 [[MuleRuntime].uber.04: [aggregator-time-demo].aggregator-time-demoFlow.CPU_INTENSIVE @59b15997] [processor: aggregator-time-demoFlow/processors/1/route/0/processors/0; event: a6b00280-c933-11eb-a825-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental step.
INFO 2021-06-09 12:02:06,071 [[MuleRuntime].uber.04: [aggregator-time-demo].aggregator-time-demoFlow.CPU_INTENSIVE @59b15997] [processor: aggregator-time-demoFlow/processors/1/route/0/processors/0; event: a7cd0b40-c933-11eb-a825-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental step.
INFO 2021-06-09 12:02:09,206 [[MuleRuntime].uber.04: [aggregator-time-demo].aggregator-time-demoOnCompleteFlow.CPU_LITE @2ab3c271] [processor: aggregator-time-demoOnCompleteFlow/processors/0; event: 827c9591-c933-11eb-a825-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Aggregation complete
INFO 2021-06-09 12:02:09,208 [[MuleRuntime].uber.04: [aggregator-time-demo].aggregator-time-demoOnCompleteFlow.CPU_LITE @2ab3c271] [processor: aggregator-time-demoOnCompleteFlow/processors/1; event: 827c9591-c933-11eb-a825-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: [
 {
  "Source Name": "time-based",
  "Source ID": "0.7095971146328517"
 },
 {
  "Source Name": "time-based",
  "Source ID": "0.6900116288202388"
 }
]
```

This example logger message shows that for each HTTP request, the **Logger** component in the **Incremental aggregator** route logs the message `Doing incremental step.` After the `timeBasedAggregator` value that is referenced by the **Aggregator listener** source completes the incremental aggregations within `5` seconds, the listener is triggered with a list of all the elements. The subsequent **Logger** component logs the message `Aggregation complete`, and the second **Logger** component returns the aggregated payload elements, which are the random ID numbers:
```
{
 "Source Name": "time-based",
 "Source ID": "0.7095971146328517"
},
{
 "Source Name": "time-based",
 "Source ID": "0.6900116288202388"
}
```

## XML for Time-Based Aggregator Example
Paste this code into your Studio XML editor to quickly load the flow for this example into your Mule app:
```
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:aggregators="http://www.mulesoft.org/schema/mule/aggregators" xmlns:ee="http://www.mulesoft.org/schema/mule/ee/core"
	xmlns:http="http://www.mulesoft.org/schema/mule/http"
	xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/core http://www.mulesoft.org/schema/mule/ee/core/current/mule-ee.xsd
http://www.mulesoft.org/schema/mule/aggregators http://www.mulesoft.org/schema/mule/aggregators/current/mule-aggregators.xsd">
	<http:listener-config name="HTTP_Listener_config" >
		<http:listener-connection host="0.0.0.0" port="8086" />
	</http:listener-config>
	<flow name="aggregator-time-demoFlow" >
		<http:listener config-ref="HTTP_Listener_config" path="/test" allowedMethods="POST"/>
		<ee:transform >
			<ee:message >
				<ee:set-payload ><![CDATA[%dw 2.0
output application/json
---
{
  "Source Name": "time-based",
  "Source ID": (random() as String)
}]]></ee:set-payload>
			</ee:message>
		</ee:transform>
		<aggregators:time-based-aggregator period="5" name="timeBasedAggregator">
			<aggregators:incremental-aggregation >
				<logger level="INFO" message="Doing incremental step."/>
			</aggregators:incremental-aggregation>
		</aggregators:time-based-aggregator>
	</flow>
	<flow name="aggregator-time-demoOnCompleteFlow" >
		<aggregators:aggregator-listener aggregatorName="timeBasedAggregator"/>
		<logger level="INFO" message="Aggregation complete" />
		<logger level="INFO" message="#[output application/json
---
payload]" />
	</flow>
</mule>
```

## See Also
  * Aggregators Module Examples
  * MuleSoft Help Center