Invoke Java Method in Mule Flow

Since Mule is being built on top of Java and Spring their is strong integration capability in mule to invoke Java methods. Their are numerous ways to invoke a java method in Mule. Today I will be showing how to use one such component in mule i.e. called Invoke Component .

Invoke Component

package com.demo.entrypoint;

public class InvokeSpringSample {

	public String methodA() {
		System.out.println("Method A of Spring bean sample activated");
		return "Method A";
	}

	public void methodB() {
		System.out.println("Method B of Spring bean sample activated");
	}

	public String methodC(String inputA, String inputB) {
		System.out.println("Method B of Spring bean sample activated");
		return "Method C got " + inputA + " and " + inputB;
	}

}

Mule Flow

In our mule flow xml file lets define a spring bean by which we will be invoking the java class

as you see we have not defined anything special and above bean is just plain old spring bean.

Next Drag the HTTP connector as your flow inbound endpoint and next drag the invoke component from the mule palette

Below are the properties you can see in invoke component

 Complete Flow

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" 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: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/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"/>

    <spring:beans>
    	<spring:bean class="com.demo.entrypoint.InvokeSpringSample" name="invokeSpringBean">

    	</spring:bean>

    </spring:beans>

    <flow name="invoke-component-demoFlow">
        <http:listener config-ref="HTTP_Listener_Configuration" path="/invoke" doc:name="HTTP"/>
        <invoke object-ref="invokeSpringBean" method="methodA" doc:name="Invoke Spring Bean Method A"/>
        <echo-component doc:name="Echo"/>
        <invoke object-ref="invokeSpringBean" method="methodB" doc:name="Invoke Spring Bean Method B"/>
        <echo-component doc:name="Echo"/>
        <invoke object-ref="invokeSpringBean" method="methodC" doc:name="Invoke Spring Bean Method C" methodArguments="#[message.inboundProperties.'http.query.params'.['name']],#[message.inboundProperties.'http.query.params'.['age']]"/>
        <echo-component doc:name="Echo"/>
    </flow>
</mule>

Test

using postman make a call to your endpoint and supplying query parameter for name and age http://localhost:8081/invoke?name=harish&age=30

All your component will be invoked with arguments or no argument and will be processed below is the screen shot of the log.

Video Demo

Youtube video here https://youtu.be/-T3AGGBdqTA

Conclusion

This is just one way of calling a java method in mule, in my next blog I will be talking about Entry point resolvers in mule ESB.

I hope you liked the video and the blog, please do comment and share and subscribe to give me more motivation to keep bringing good stuff to you all.

Thank you.