Order Approval Service

Introduction

This sample demonstrates an order approval process which uses business rules to check whether the required conditions for approving an order are met.

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 : An order for stocks of Company IBM is accepted only if the number of stocks is higher than 10.
Rule 2 : An order for stocks of Company SUN is accepted only if the stock price is higher than 100 $.
Rule 3 : An order for stocks of Company MSFT is accepted only if the stock price is higher than 50 $ and the number of stocks is lower than 200.

Facts

There is one fact named Order. OrderAccept and OrderReject are used to capture the result of the service.

Rule service configuration (service.rsl) 

<ruleService
        name="OrderApprovalService"
        xmlns="http://wso2.org/carbon/rules"
        targetNamespace="http://com.test/orderApproval">
  <ruleSet>
        <rule resourceType="regular" sourceType="file">orderApprovalRules.drl</rule>
    </ruleSet>
    <operation name="placeOrder">
        <input wrapperElementName="placeOrder" namespace="http://com.test/placeorder">
            <fact elementName="order" namespace="http://com.test/placeorder" type="samples.userguide.PlaceOrder"></fact>
        </input>
        <output wrapperElementName="placeOrderRespone" namespace="http://com.test/placeorder">
            <fact elementName="orderAccept" namespace="http://com.test/placeorder" type="samples.userguide.OrderAccept"></fact>
            <fact elementName="orderReject" namespace="http://com.test/placeorder" type="samples.userguide.OrderReject"></fact>
        </output>
    </operation>
</ruleService>

Executing the service

To execute the service, run the ant command from the  <PRODUCT_HOME>/samples/quotation.service directory to run the OrderApproval Service.

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, click on List under Services in the main tab of the management console. The service will appear in the Deployed Services page.
3. Click OrderApproval to access the dashboard of the service.
4. Click Try this service in the Client Operations widget of the dashboard to invoke the Try-it tool.

5. Issue a request similar to the following in the Try-it tool.
    

   <price>10</price>
   <quantity>9</quantity>
   <symbol>IBM</symbol> 

   
   You would get the following response:
   
   

     <orderReject>
         <reason>An Order for stocks of IBM is accepted only if the number of stocks is higher than 10.</reason>
     </orderReject>

6. Enter another request as follows:

   <price>120</price>
   <quantity>100</quantity>
   <symbol>SUN</symbol> 

   You would get the following response

    <orderAccept>
         <message>Accepted order for: 100 stocks of SUN at$ 120.0</message>
      </orderAccept>

7. Enter another request as follows:

   <price>50</price>
   <quantity>160</quantity>
   <symbol>MSFT</symbol> 

   
   You would get the following result: 

     <orderReject>
         <reason>An Order for stocks of MSFT is accepted only if the stock price is higher than 50 $ and the number of stocks is lower than 200.</reason>
      </orderReject>

8. Alternatively, you can use Generate Axis2 Client 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 the Unpacks the data binding classes check box checked. 

   package test.com.orderapproval;
           
           /*
           *  OrderApprovalServiceStub java implementation
           */
           
           public class OrderApprovalServiceStub extends org.apache.axis2.client.Stub
           {
           protected org.apache.axis2.description.AxisOperation[] _operations;
           //hashmaps to keep the fault mapping
           private java.util.HashMap faultExceptionNameMap = new java.util.HashMap();
           private java.util.HashMap faultExceptionClassNameMap = new java.util.HashMap();
           private java.util.HashMap faultMessageMap = new java.util.HashMap();
           private static int counter = 0;
           private static synchronized java.lang.String getUniqueSuffix(){
               // reset the counter if it is greater than 99999
               if (counter > 99999){
                   counter = 0;
               }
               counter = counter + 1; 
               return java.lang.Long.toString(java.lang.System.currentTimeMillis()) + "_" + counter;
           }
       
       private void populateAxisService() throws org.apache.axis2.AxisFault {
        //creating the Service with a unique name
        _service = new org.apache.axis2.description.AxisService("OrderApprovalService" + getUniqueSuffix());
        addAnonymousOperations();
           //creating the operations
           org.apache.axis2.description.AxisOperation __operation;
           _operations = new org.apache.axis2.description.AxisOperation[1];
           
                      __operation = new org.apache.axis2.description.OutInAxisOperation();
                   
               __operation.setName(new javax.xml.namespace.QName("http://com.test/orderApproval", "placeOrder"));
   	    _service.addOperation(__operation);