This document provides an example of using a REST component in Mule to create a RESTful API for arithmetic operations. It defines a Java class with POST methods for addition, subtraction, and multiplication that accept JSON payloads and return JSON responses. The REST component is configured in a flow with an HTTP inbound endpoint to expose the operations at URLs. Details are provided on testing the API by triggering the methods and viewing the responses.

1. REST Component

2. Abstract
 The main motto of this PPT is How to use REST
Component in our applications.

3. Introduction
 REST stands for Representational State
Transfer. REST exposes a much simpler
interface than SOAP. REST components are
bound with HTTP. So, if you are designing
an application to be used exclusively on the Web,
REST is a very good option. RESTful applications
simply rely on the built-in HTTP security. A REST
design is good for database-driven applications
and also when a client wants quick integration.

4. SOAP Component POC:
Link: https://youtu.be/h-aJIjt9TcQ
How to do above POC using REST component?

5. Example
ArthematicOperations
a. Addition
b. Subtraction
c. Multiplication

7. .mflow
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:jersey="http://www.mulesoft.org/schema/mule/jersey"
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" version="EE-3.4.0"
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/jersey
http://www.mulesoft.org/schema/mule/jersey/current/mule-jersey.xsd">
<flow name="RestComponentFlow1" doc:name="RestComponentFlow1">
<http:inbound-endpoint exchange-pattern="request-response" host="localhost" port="8098"
doc:name="HTTP"/>
<logger message="---Entered into the flow" level="INFO" doc:name="Logger"/>
<jersey:resources doc:name="REST">
<component class="com.ArthematicOperations"/>
</jersey:resources>
</flow>
</mule>

8. com.ArthematicOperations:
 package com;
 import javax.ws.rs.Consumes;
 import javax.ws.rs.POST;
 import javax.ws.rs.Path;
 import javax.ws.rs.Produces;
 import javax.ws.rs.core.MediaType;
 import org.codehaus.jackson.JsonNode;
 import org.codehaus.jettison.json.JSONObject;
 @Path("/")
 public class ArthematicOperations {
 @POST
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 @Path("Addition")
 public Object addition(JsonNode inputJSON) throws Exception {
 JSONObject jsonStatus = new JSONObject();
 jsonStatus.put("Result",(Integer.parseInt(inputJSON.get("Num1").getTextValue())+Integer.parseInt(inputJSON.get("Num2").getTextValue())));
 return jsonStatus.toString();
 }
 @POST
 @Consumes(MediaType.APPLICATION_JSON)
 @Produces(MediaType.APPLICATION_JSON)
 @Path("Subtraction")
 public Object subtraction(JsonNode inputJSON) throws Exception {JSONObject jsonStatus = new JSONObject();
 jsonStatus.put("Result",(Integer.parseInt(inputJSON.get("Num1").getTextValue())-Integer.parseInt(inputJSON.get("Num2").getTextValue())));
 return jsonStatus.toString();
 }
 @POST
 @Consumes(MediaType.APPLICATION_JSON)
 @Produces(MediaType.APPLICATION_JSON)
 @Path("Multiplication")
 public Object multiplication(JsonNode inputJSON) throws Exception {JSONObject jsonStatus = new JSONObject();

9. How to test this?
URLs
Addition: http://localhost:8098/Addition
Subtraction: http://localhost:8098/Subtraction
Multiplication: http://localhost:8098/Multiplication

10. Trigger the methods:
1. Addition:

11.  Console:
INFO 2015-12-15 18:09:29,554 [main] org.mule.DefaultMuleContext:
**********************************************************************
* Application: RestComponent *
* OS encoding: Cp1252, Mule encoding: UTF-8 *
* *
* Agents Running: *
* Clustering Agent *
* JMX Agent *
**********************************************************************
INFO 2015-12-15 18:09:29,556 [main] org.mule.module.launcher.MuleDeploymentService:
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Started app 'RestComponent' +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
INFO 2015-12-15 18:10:28,825 [[RestComponent].connector.http.mule.default.receiver.02]
org.mule.api.processor.LoggerMessageProcessor: ---Entered into the flow

12. References
 https://docs.mulesoft.com/mule-user-
guide/v/3.7/rest-component-reference