Greeting Service

Introduction

This sample demonstrates how to use the BRS for a simple greetings service.

Prerequisites

To run this sample:

Windows, Linux or Solaris operating system should exist.
WSO2 BRS should be installed. To install the BRS, refer Installing the Product. This also includes installing Apache Ant as one of the Installation Prerequisites.
WSO2 BRS should be started as described in Running the Product.

Sample Configuration

Sample Rule Definition

Rules

Rule 1 : If the time is between 12 and 18, say good afternoon.

Rule 2 : If the time is between 6 and 12, say good morning.

Rule 3 : If the time is between 18 and 24, say good night.

Facts

There is a fact named A user logged in into the system. GreetingMessage is used to capture the result of the rule execution.

package samples.greeting;
import java.util.Calendar;

/**
 * User
 */
public class User {
    private String name ;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int now(){
        Calendar cal = Calendar.getInstance();
        return cal.get(Calendar.HOUR_OF_DAY);
    }
}
    
package samples.greeting;
/**
 * greeting message
 */
public class GreetingMessage {
    private String message ;
    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
}

Rule Service Configuration (service.rsl)

An in-line rule set is used within the service.rsl file as follows.

<ruleService
       name="GreetingService"
       xmlns="http://wso2.org/carbon/rules"
       targetNamespace="http://com.test/greeting">
    <ruleSet>
       <rule resourceType="regular" sourceType="inline">
           <![CDATA[
               package greeting

               import samples.greeting.GreetingMessage;
               import samples.greeting.User;

               rule "Is Morning" no-loop true
               when
                   user : User()
                   eval((6 < user.now()) && (user.now()< 12))
               then
                   GreetingMessage msg = new GreetingMessage();
                   msg.setMessage("Good Morning  " + user.getName() + " !!! ");
                   insertLogical(msg);
               end

               rule "Is afternoon" no-loop true
               when
                   user : User()
                   eval((12 <= user.now()) && (user.now() < 18))
               then
                   GreetingMessage msg = new GreetingMessage();
                   msg.setMessage("Good Afternoon  " + user.getName() + " !!! ");
                   insertLogical(msg);
               end

               rule "Is Night" no-loop true
               when
                   user : User()
                   eval( (18 <= user.now()) && (user.now() < 24))
               then
                   GreetingMessage msg = new GreetingMessage();
                   msg.setMessage("Good Night  " + user.getName() + " !!! ");
                   insertLogical(msg);
               end
           ]]>
       </rule>
    </ruleSet>
    <operation name="greetMe">
       <input wrapperElementName="user" namespace="http://com.test/greeting">
           <fact elementName="user" namespace="http://com.test/greeting" type="samples.greeting.User"></fact>
       </input>
       <output wrapperElementName="greetingMessage" namespace="http://com.test/greeting">
           <fact elementName="greetingMessage" namespace="http://com.test/greeting" type="samples.greeting.GreetingMessage"></fact>
       </output>
    </operation>
</ruleService>

Executing the Sample

To execute the sample, run the ant command from the <PRODUCT_HOME>/samples/greeting.service directory to run the Greetings Service.

Before executing this sample, it is recommended that you refer Exposing Rules as Services which explains in detail the process of writing and deploying a business rule.

Deploying and Testing the Sample

Deploy the rule service through the BRS management console. You can follow either of the two methods:
- Bundle all artifacts in an .aar file and upload it (Rule Service -> Upload menu).
- Create using the Rule Service wizard UI (Rule Service -> Create menu).
The above steps are discussed in detail in section Exposing Rules as Services.
After deployment, click on List under Services in the main tab of the management console. The service will appear in the Deployed Services page.
Click Greeting Service to access the dashboard of the service.
Click Try this service in the Client Operations widget of the dashboard to invoke the Try-it tool.
Issue a request similar to the following in the Try-it tool:
```
<name>your name</name>
```
You would get the following response:
```
<message>Good Early Morning  Test Name !!! </message>
```

Alternatively, you can click Generate Axis 2 Client in the Client Operations widget of the dashboard to invoke the service. A client using generated stub codes is shown below where the codes were generated with the Unpacks the databinding classes check box checked.

package org.wso2.carbon.samples;

import java.lang.String;
import org.wso2.carbon.samples.greetingService.greeting.*;
import org.apache.axis2.AxisFault;
import java.rmi.RemoteException;

public class GreetingServiceTestCase {

    public static void main(String[] args) {

        try {
            GreetingServiceStub greetingServiceStub = new GreetingServiceStub("http://localhost:9763/services/GreetingService");

            UserE userRequest = new UserE();
            User user = new User();
            user.setName("your name");
            User[] users = new User[1];
            users[0] = user;
            userRequest.setUser(users);

            GreetingMessage[] greetingMessages = greetingServiceStub.greetMe(users);
            String result = greetingMessages[0].getMessage();
            System.out.println(result);

        } catch (AxisFault axisFault) {
            axisFault.printStackTrace();
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }
}