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Invoking Multiple Operations via Request Box

This example demonstrates how a data service can invoke request box operations. The request box feature allows you to invoke multiple operations (consecutively) to a datasource using a single operation.

Boxcarring is a method of grouping a set of service calls so that they can be executed as a group (i.e., the individual service calls are executed consecutively in the specified order). Note that we have now deprecated the boxcarring method for data services. Instead, we have replaced boxcarring with a new request type called request_box .

Request box is simply a wrapper element (request_box), which wraps the service calls that need to be invoked. When the request_box is invoked, the individual service calls are executed in the specified order, and the result of the last service call in the list are returned. In this tutorial, we are using the request box to invoke the following two service calls:

  1. Add a new employee to the database
  2. Get details of the office of the added employee

When you click the Enable Boxcarring check box for the data service, both of the above functions (Boxcarring and Request box) are enabled. However, since boxcarring is deprecated in the product, it is recommended to disable boxcarring by clicking the Disable Legacy Boxcarring Mode check box.

Prerequisites

Let's create a MySQL database with the required data.

  1. Install the MySQL server.
  2. Create a database named Company.

    CREATE DATABASE Company;
  3. Create the Employees table:

    USE Company;
    
    CREATE TABLE `Employees` (`EmployeeNumber` int(11) NOT NULL, `FirstName` varchar(255) NOT NULL, `LastName` varchar(255) DEFAULT NULL, `Email` varchar(255) DEFAULT NULL, `JobTitle` varchar(255) DEFAULT NULL, `OfficeCode` int(11) NOT NULL, PRIMARY KEY (`EmployeeNumber`,`OfficeCode`));

Synapse configuration

Given below is the data service configuration you need to build. See the instructions on how to build and run this example.

<data disableLegacyBoxcarringMode="true" enableBoxcarring="true" name="request_box_example" transports="http https local">
   <config enableOData="false" id="Datasource">
      <property name="driverClassName">com.mysql.jdbc.Driver</property>
      <property name="url">jdbc:mysql://localhost:3306/Company</property>
   </config>
   <query id="addEmployeeQuery" useConfig="Datasource">
      <sql>insert into Employees (EmployeeNumber, FirstName, LastName, Email,OfficeCode) values(:EmployeeNumber,:FirstName,:LastName,:Email,:OfficeCode)</sql>
      <param name="EmployeeNumber" sqlType="STRING"/>
      <param name="FirstName" sqlType="STRING"/>
      <param name="LastName" sqlType="STRING"/>
      <param name="Email" sqlType="STRING"/>
      <param name="OfficeCode" sqlType="STRING"/>
   </query>
   <query id="selectEmployeebyIDQuery" useConfig="Datasource">
      <sql>select EmployeeNumber, FirstName, LastName, Email, OfficeCode from Employees where EmployeeNumber=:EmployeeNumber</sql>
      <result element="Entries" rowName="Entry">
         <element column="EmployeeNumber" name="EmployeeNumber" xsdType="string"/>
         <element column="FirstName" name="FirstName" xsdType="string"/>
         <element column="LastName" name="LastName" xsdType="string"/>
         <element column="Email" name="Email" xsdType="string"/>
         <element column="OfficeCode" name="OfficeCode" xsdType="string"/>
      </result>
      <param name="EmployeeNumber" sqlType="STRING"/>
   </query>
   <operation name="addEmployeeOp">
      <call-query href="addEmployeeQuery">
         <with-param name="EmployeeNumber" query-param="EmployeeNumber"/>
         <with-param name="FirstName" query-param="FirstName"/>
         <with-param name="LastName" query-param="LastName"/>
         <with-param name="Email" query-param="Email"/>
         <with-param name="OfficeCode" query-param="OfficeCode"/>
      </call-query>
   </operation>
   <operation name="selectEmployeeOp">
      <call-query href="selectEmployeebyIDQuery">
         <with-param name="EmployeeNumber" query-param="EmployeeNumber"/>
      </call-query>
   </operation>
</data>

Build and run

Create the artifacts:

  1. Set up WSO2 Integration Studio. The path to this folder is referred to as MI_TOOLING_HOME throughout this tutorial.
  2. Download the JDBC driver for MySQL from here and copy it to the MI_TOOLING_HOME/Contents/Eclipse/runtime/microesb/lib/ (for MacOS) or MI_TOOLING_HOME/runtime/microesb/lib/ (for Windows) directory.

    Note

    If the driver class does not exist in the relevant folders when you create the datasource, you will get an exception such as Cannot load JDBC driver class com.mysql.jdbc.Driver.

  3. Create a Data Service project

  4. Create the data service with the configurations given above.
  5. Deploy the artifacts in your Micro Integrator.

Send a request with multiple transactions as shown below. In this example, we are sending two transactions with details of two employees.

<p:request_box xmlns:p="http://ws.wso2.org/dataservice">
  <!--Exactly 1 occurrence-->
  <addEmployeeOp xmlns="http://ws.wso2.org/dataservice">
     <!--Exactly 1 occurrence-->
     <xs:EmployeeNumber xmlns:xs="http://ws.wso2.org/dataservice">1003</xs:EmployeeNumber>
     <!--Exactly 1 occurrence-->
     <xs:FirstName xmlns:xs="http://ws.wso2.org/dataservice">Chris</xs:FirstName>
     <!--Exactly 1 occurrence-->
     <xs:LastName xmlns:xs="http://ws.wso2.org/dataservice">Sam</xs:LastName>
     <!--Exactly 1 occurrence-->
     <xs:Email xmlns:xs="http://ws.wso2.org/dataservice">chris@sam.com</xs:Email>
     <!--Exactly 1 occurrence-->
     <xs:OfficeCode xmlns:xs="http://ws.wso2.org/dataservice">1</xs:OfficeCode>
  </addEmployeeOp>
  <!--Exactly 1 occurrence-->
  <selectEmployeeOp xmlns="http://ws.wso2.org/dataservice">
     <!--Exactly 1 occurrence-->
     <xs:EmployeeNumber xmlns:xs="http://ws.wso2.org/dataservice">1003</xs:EmployeeNumber>
  </selectEmployeeOp>
</p:request_box>
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