This documentation is for WSO2 Business Rules Server 2.0.0.View documentation for the latest release.
                                                                                                                                                                                                                                                                                                                                           
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This sample demonstrates a service for calculating Mortgage Insurance Premium (PMI) using business rules.

Note

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

Sample Rule Definition

Rules

Rule 1 : The mortgage insurance rate for PMI insurance is 0.5 and for FHA loans, it is 1.5.

Facts

There is one fact and a result as Client and Mortgage Insurance Premium.

package samples.MIPCalculate;

/**
 * Client fact
 */
public class Client {

    private String loanType;

    private double mortgageValue;

    private double downPayment;

    public String getLoanType() {
        return loanType;
    }

    public void setLoanType(String loanType) {
        this.loanType = loanType;
    }

    public double getMortgageValue() {
        return mortgageValue;
    }

    public void setMortgageValue(double mortgageValue) {
        this.mortgageValue = mortgageValue;
    }

    public double getDownPayment() {
        return downPayment;
    }

    public void setDownPayment(double downPayment) {
        this.downPayment = downPayment;
    }
}

package samples.MIPCalculate;

/**
 * MIP - Mortgage Insurance Premium
 */
public class MIP {

    private double annualMIP;

    public double getAnnualMIP() {
        return annualMIP;
    }

    public void setAnnualMIP(double annualMIP) {
        this.annualMIP = annualMIP;
    }
}

Rule Service Configuration (service.rsl)

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

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

                import samples.MIPCalculate.Client;
                import samples.MIPCalculate.MIP;

                rule "Calculate the MIP for PMI " no-loop true
                when
                    user : Client(loanType == "PMI")
                then
                    MIP mip = new MIP();
                    double loanAmount = user.getMortgageValue() - user.getDownPayment();
                    double lvt = loanAmount / user.getMortgageValue();
                    double lvtAmount = lvt * user.getMortgageValue();
                    mip.setAnnualMIP(lvtAmount * 0.05);
                    insertLogical(mip);

                end

                rule "Calculate the MIP for FHA loan" no-loop true
                when
                    user : Client(loanType == "FHA")
                then
                    MIP mip = new MIP();
                    double loanAmount = user.getMortgageValue() - user.getDownPayment();
                    double lvt = loanAmount / user.getMortgageValue();
                    double lvtAmount = lvt * user.getMortgageValue();
                    mip.setAnnualMIP(lvtAmount * 0.15);
                    insertLogical(mip);
                end
            ]]>
        </rule>
    </ruleSet>
    <operation name="calculate">
        <input wrapperElementName="placeClientDetail" namespace="http://com.test/placeClientDetail">
            <fact elementName="clientDetail" namespace="http://com.test/placeClientDetail" type="samples.MIPCalculate.Client"></fact>
        </input>
        <output wrapperElementName="placeClientDetailRespone" namespace="http://com.test/placeClientDetail">
            <fact elementName="MIP" namespace="http://com.test/placeClientDetail" type="samples.MIPCalculate.MIP"></fact>
        </output>
    </operation>
</ruleService>

Deploying and Testing the Service

1. 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.

2. After deployment, the service will appear in the "Deployed Services" window of the BRS management console. Access the service's dashboard by clicking on it.

3. In the "Client Operations" widget of the dashboard, invoke the Try-it tool to test the service.

4. In the service's TryIt window, issue a request similar to the following.

<loanType>FHA</loanType>
<mortgageValue>100000</mortgageValue>
<downPayment>90000</downPayment>
Similarly, another request can be sent:
<loanType>PMI</loanType>
<mortgageValue>100000</mortgageValue>
<downPayment>90000</downPayment>

5. Alternatively, you can use code generation link 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 option "Unpacks the databinding classes".

package org.wso2.carbon.samples;

import org.apache.axis2.AxisFault;
import org.wso2.carbon.samples.mipCalculateService.clientDetail.Client;
import org.wso2.carbon.samples.mipCalculateService.clientDetail.MIP;
import org.wso2.carbon.samples.mipCalculateService.clientDetail.PlaceClientDetail;
import org.wso2.carbon.samples.mipCalculateService.stub.MIPCalculateServiceStub;
import java.rmi.RemoteException;

public class MIPCalculateServiceTestCase {

    public static void main(String[] args) {

        try {
            MIPCalculateServiceStub mipCalculateServiceStub =
                    new MIPCalculateServiceStub("http://localhost:9763/services/MIPCalculateService");
            PlaceClientDetail placeClientDetail = new PlaceClientDetail();

            Client client = new Client();
            client.setLoanType("FHA");
            client.setDownPayment(8000);
            client.setMortgageValue(90000);
            Client[] clients = new Client[1];
            clients[0] = client;

            MIP[] mips = mipCalculateServiceStub.calculate(clients);
            double result = mips[0].getAnnualMIP();
            System.out.println(result);

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