Splitter and Collection Aggregator With Mulesoft

Splitter is used to split Mule messages into separate fragments. Each fragment is then sent one at a time to the next processor in the flow. Segments are identified by expression parameters and are generally written in MEL (Mule Expression Language). You can then use a Collection Aggregator Flow Control to reassemble the parts of the original message.

Now, we will walk through how to use Splitter in your Mule flow.

Splitting the Message Payload

Place the HTTP listener into the canvas and click to open the Properties console.

Click the green + and configure as follows:

• Host: localhost.

• Port: 8081.

• Method: POST.

• Path: slitter.

Place the Splitter component in Message processor region after HTTP Listener.

Configure the Splitter component as shown below.

Place the DOM to XML transformation after Splitter, as it will convert the split message object into XML.

Finally, place the file connector at the end of message processor to save all split messages.

Testing Application

You can use Postman to post the message. The listening URL will be http://localhost:8081/splitter.

Sample input message:

<Employees>
<Employee>
<FirstName>Jitu</FirstName>
<LastName>Jain</LastName>
<Salary>100000</Salary>
</Employee>
<Employee>
<FirstName>Jospeh</FirstName>
<LastName>Adams</LastName>
<Salary>200000</Salary>
</Employee>
<Employee>
<FirstName>Steve</FirstName>
<LastName>Simon</LastName>
<Salary>300000</Salary>
</Employee>
<Employee>
<FirstName>Brain</FirstName>
<LastName>Handscomb</LastName>
<Salary>300000</Salary>
</Employee>
<Employee>
<FirstName>Rajeev</FirstName>
<LastName>Thandani</LastName>
<Salary>500000</Salary>
</Employee>
</Employees>

The above sample input message will be split into five messages and will be saved to file location as five different files.

Now, you can verify the file location and check if the message is properly split into five different files.

Code:

<?xml version="1.0" encoding="UTF-8"?>
<mule
xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking"
xmlns:file="http://www.mulesoft.org/schema/mule/file"
xmlns:http="http://www.mulesoft.org/schema/mule/http"
xmlns:mulexml="http://www.mulesoft.org/schema/mule/xml"
xmlns="http://www.mulesoft.org/schema/mule/core"
xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:spring="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
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/file http://www.mulesoft.org/schema/mule/file/current/mule-file.xsd
http://www.mulesoft.org/schema/mule/xml http://www.mulesoft.org/schema/mule/xml/current/mule-xml.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd">
<http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8081" doc:name="HTTP Listener Configuration"/>
<flow name="splitterprojectFlow">
<http:listener config-ref="HTTP_Listener_Configuration" path="/splitter" allowedMethods="POST" doc:name="HTTP"/>
<splitter expression="#[xpath('//Employee')]" doc:name="Splitter"></splitter>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
<file:outbound-endpoint path="src/test/resources/out" responseTimeout="10000" doc:name="File"/>
</flow>
</mule>

Aggregating Message Payload

When Mule splits the message, it adds three new outbound variables into each of the output fragments. This you can use later when aggregating the message.

• MULE_CORRELATION_GROUP_SIZE: Number of fragments into which the original message was split.

• MULE_CORRELATION_SEQUENCE: Position of a fragment within the group.

•  MULE_CORRELATION_ID: Single ID for the entire group (all output fragments of the same original message share the same value).

These three variables play an important role while aggregating the message, as they know what group to put it into and what the size of group is. Once all the split messages are received, it passes any split messages into one aggregated group.In continuation with above example, place Collection Aggregator after Splitter.

Collection Aggregator will aggregate all the split messages into a single payload.

Code:

<?xml version="1.0" encoding="UTF-8"?>
<mule
xmlns:json="http://www.mulesoft.org/schema/mule/json"
xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking"
xmlns:file="http://www.mulesoft.org/schema/mule/file"
xmlns:http="http://www.mulesoft.org/schema/mule/http"
xmlns:mulexml="http://www.mulesoft.org/schema/mule/xml"
xmlns="http://www.mulesoft.org/schema/mule/core"
xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:spring="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
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/file http://www.mulesoft.org/schema/mule/file/current/mule-file.xsd
http://www.mulesoft.org/schema/mule/xml http://www.mulesoft.org/schema/mule/xml/current/mule-xml.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd
http://www.mulesoft.org/schema/mule/json http://www.mulesoft.org/schema/mule/json/current/mule-json.xsd">
<http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8081" doc:name="HTTP Listener Configuration"/>
<flow name="splitterprojectFlow">
<http:listener config-ref="HTTP_Listener_Configuration" path="/splitter" allowedMethods="POST" doc:name="HTTP"/>
<splitter expression="#[xpath('//Employee')]" doc:name="Splitter"></splitter>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
<collection-aggregator failOnTimeout="true" doc:name="Collection Aggregator">
<expression-message-info-mapping messageIdExpression="#[message.id]" correlationIdExpression="#[message.correlationId]"/>
</collection-aggregator>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
<file:outbound-endpoint path="src/test/resources/out" responseTimeout="10000" doc:name="File"/>
</flow>
</mule>

Now, you know how to use Splitter and Collection Aggregator within a Mule flow.

Here is the video tutorial: