Getting Started with OpenL Tablets

Introduction

The purpose of this tutorial is to help you get started with OpenL Tablets. This page describes how to start using OpenL Tablets with a simple example.

In the course of this tutorial, we will create a simple rule based on existing requirements in an Excel file and show how to verify that it works.

OpenL Tablets is a business rules management system based on tables presented in Excel documents. Providing a business-oriented approach, OpenL Tablets treats business documents containing business logic specifications as executable rules. In a very simplified view, OpenL Tablets extracts rule tables from Excel documents and executes them. The rules can be accessible from different applications. OpenL Tablets tools check all data, syntax, and type errors in order to avoid any user mistakes.

OpenL Studio is a web interface application employed by business users and rules experts to view, edit, and manage business rules and rule projects created using OpenL Tablets technology.

OpenL Studio and Excel are used for comfortable work of business analysts and subject matter experts with OpenL Tablets rules, allowing them to represent, test, and maintain business logic.

Before we dive in, here are the OpenL Tablets basic concepts:

Concept Description
Rules In OpenL Tablets, a basic rule is a logical statement consisting of conditions, actions, and returned values. If a rule is evaluated and all its conditions are true, then the corresponding actions are executed and/or the result value is returned to the calling program. Basically, a rule is an IF-THEN statement. There are calculator and workflow (algorithm) rule representations as well.
Tables Basic information that OpenL Tablets deals with, such as rules and data, is presented in tables. OpenL Tablets offers different types of tables for different types of processing. OpenL includes rule table types such as decision tables, lookup tables, decision trees, and spreadsheet-like calculators.
Projects An OpenL Tablets project is a container of all resources required for processing rule-related information. Usually, a simple project contains just Excel files with rules.

More details can be found in OpenL Tablets Reference Guide, Chapter 1: Introducing OpenL Tablets.

Quick Start

To start working with OpenL Studio, you can use our online demo. Please note that it is for demonstration purposes only and all the content is deleted from it once a day.

Use the following links to the applications of our Live Demo:

Demo Application URL
OpenL Studio http://demo.openl-tablets.org/webstudio
Rule Services http://demo.openl-tablets.org/webservice
Rule Services client example http://demo.openl-tablets.org/webservice-client.html

For more details on OpenL Tablets Demo, you can refer to OpenL Tablets Demo Package Guide. You can always download and install OpenL Tablets Demo for yourself by following this guide.

When you open OpenL Studio, you will see the OpenL Studio start page in your browser:

Figure 1: OpenL Studio Home page

Figure 1: OpenL Studio Home page

Rule Creation

OpenL Tablets utilizes Excel concepts of workbooks and worksheets containing rules. A rule project where rules are maintained consists of Excel files that are called modules. Each workbook is comprised of one or more worksheets used to separate information by logical categories (so you will understand your rules better). Each worksheet, in turn, is comprised of one or more OpenL tables that represent rules. Workbooks can include rule tables of different types and different underlying logic.

Rules can be created with the following tools:

  1. OpenL Studio Table Wizards.
  2. Microsoft Excel. In this case, the rule file should be uploaded in OpenL Studio where it will be validated and properly tested.

In this tutorial, we are going to see the creation of a rule and its test in Microsoft Excel, and then their updating and testing in OpenL Studio. You can also create the same rule directly in OpenL Studio using the Simple Rules Table Wizard on your own.

Details about creating rules and different rule table types can be found in OpenL Tablets Reference Guide, Creating Tables for OpenL Tablets.

Here we are going to create a business rule according to an Excel file that contains requirements. The idea is that by slightly modifying the original requirements, we can create ready-to-execute OpenL rules without any special effort and with little special knowledge.

‘Air Ticket Price’ Rule Creation in Excel

The following example demonstrates how to create a simple rule that determines the air ticket price value depending on a city of departure and a city of destination. For example, if the departure city is Chicago and the destination city is Madrid, we want our rules to return $900 as an air ticket price.

The business requirements are represented as the following Excel table in the TicketsPrice.xls file:

Figure 2: A spreadsheet requirements for Air Tickets Price rule

Figure 2: A spreadsheet requirements for Air Tickets Price rule

To enable this table as an executable rule table, all you need to do is add several OpenL Tablets instructions.

This table matches the Simple Decision Table structure. To instruct OpenL how to treat your rules and to specify that the table is a Simple Decision Table, add a new row just above the requirements table, merge its cells across the table width, and enter the corresponding OpenL Tablets instruction with the following content:

SimpleRules Double AirTicketsPrice (String departureCity, String destinationCity)

Figure 3: Adding a table header with OpenL Tablets instructions

Figure 3: Adding a table header with OpenL Tablets instructions

Here:

  • SimpleRules is the keyword identifying a decision table. It instructs OpenL how to process your table.
  • Double and String are type names specifying the value types returned by the rule and input value types respectively. Double stands for a number with a floating point; String stands for any text input.
  • AirTicketsPrice is the name of the rule used to reference this table from other rules or your rules-consumer application.
  • departureCity and destinationCity are the names of input parameters for the rule. You can use these names anywhere in your rule. Depending on the input values that the user enters, OpenL Tablets selects the result value.

Details on data types can be found in OpenL Tablets Reference Guide, OpenL Tablets Functions and Supported Data Types.

Rule Project Creation

Now that we have the rule created and ready to use, let’s create a project with the just-created rules in OpenL Studio. We will create a project from the Excel file TicketsPrice.xls containing our AirTicketsPrice rule that we prepared in the previous step.

To do it:

  1. Switch to the Repository Editor by clicking the Repository link.

    Figure 4: Repository Editor

    Figure 4: Repository Editor

    Repository provides the following main features:

    • Organizing collaborative work within the company
    • Modifying project structure and properties
    • Managing project deployments and project revisions

  2. Click the Create Project button. The Create Project from window will appear. Select the Excel Files tab.

    Figure 5: Create Project from.. window

    Figure 5: Create Project from.. window

  3. Add and Upload the TicketsPrice.xls file.

    Figure 6: Upload Excel file

    Figure 6: Upload Excel file

  4. In the Project Name field, enter Air Ticket Price and click Create.

    Figure 7: Creating project from Excel file

    Figure 7: Creating project from Excel file

  5. Your new project Air Ticket Price appears in the Projects tree with the Editing status. This means that you can change your project and rules in it in the Rules Editor.

    Figure 8: Created Air Ticket Price project

    Figure 8: Created Air Ticket Price project

Note: OpenL Studio also allows creating projects with Tutorials and Examples quickly from the Create Project dialog.

Editing a Rule

  1. Switch to the Rules Editor using the top-level menu and select the created Decision rule from the tree on the left.

    Figure 9: Air Tickets Price Decision table in Rules Editor

    Figure 9: Air Tickets Price Decision table in Rules Editor

    Rules Editor allows you to browse rule modules (in other words — Excel files in the project), create and modify rules and other rule tables, ad-hoc test rules, and create test tables for them. OpenL Tablets verifies syntax and type errors in all tables. Moreover, Rules Editor provides calculation explanation capabilities, enabling expansion of any calculation result and viewing the source rule table for that result, so that the user gets full information on how the rule result was calculated.

  2. Now you can edit the AirTicketsPrice rule directly in OpenL Studio.

  3. Click the Edit Edit button to edit the Decision Table and update the ticket price for Atlanta/London.

    Figure 10: Air Tickets Price Decision table update

    Figure 10: Air Tickets Price Decision table update

  4. Save the updated Decision Table.

Alternatively, you can click the Open button — the rule file opens in Excel — and apply all required changes there. Your changes become available in OpenL Studio right upon saving the Excel file.

Note: This is valid only when OpenL Studio runs on your machine. If it does not — use the Export and **Update ** buttons to download the file to your machine, edit it in Excel, and then import the updated file back into the project.

Testing a Rule

OpenL Studio does not highlight the rule we created in red and the problem pane at the bottom of the page is empty. This means we have created the rule correctly.

Now let’s ensure that the rule logic is correct.

OpenL Studio has an ad hoc rule testing feature. To use it, click the Run button on the menu, input values for the test, and click the Run button in the popup.

Figure 11: Running ad hoc test

Figure 11: Running ad hoc test

The following result will appear:

Figure 12: Results of test run

Figure 12: Results of test run

The second way to test the rule is to create a test table where you define test cases — their input and expected result values. A test table calls the rule for each test case and checks whether the actual returned value matches the expected value or not. Test tables can be created and modified in OpenL Studio or Excel; it is up to you which option to choose.

Let’s create a test table for our rule in OpenL Studio.

‘Air Ticket Price’ Test Creation in OpenL Studio

To create a table for testing the AirTicketsPrice rule, proceed as follows:

  1. Click the Create Test button to create a new test while viewing the rule table.

    Figure 13: Create Test

    Figure 13: Create Test

  2. The Test Name is prefilled automatically with the decision table name and the word Test appended at the end. Click Next.

    Figure 14: Create test window

    Figure 14: Create test window

  3. Click Save, accepting the default values for the destination where the test table will be placed.

    Figure 15: Select destination window

    Figure 15: Select destination window

  4. The Test Table is created. Now you can edit the table by updating column titles (if needed) and adding test data (as with rule tables, this can be done in OpenL Studio or in the Excel file).

    Figure 16: Initial Test Table

    Figure 16: Initial Test Table

Editing a Test in Excel

  1. To edit the test in Excel, click Open in Excel and update the table in the opened Excel file.

    Figure 17: Test Table being updated in Excel file

    Figure 17: Test Table being updated in Excel file

  2. Save the changes made in Excel. Your changes become available in OpenL Studio right upon saving the Excel file.

    Note: If OpenL Studio does not run on your machine, you need to update the file in OpenL Studio — click the * *Update** button and upload the updated version of the file.

  3. The Test Table is refreshed and the updated data is displayed in OpenL Studio.

    Figure 18: Updated Test Table in OpenL Studio

    Figure 18: Updated Test Table in OpenL Studio

Editing a Test in OpenL Studio

  1. Click the Edit Edit button to edit the test table in OpenL Studio.

  2. Add test data:

    a. Click on any table cell. The table editor menu becomes enabled.

    b. In the table editor menu, select the Insert row button to insert a row before the selected one. Insert two rows.

    Figure 19: Table editor menu

    Figure 19: Table editor menu

    c. Add test data and Save your changes.

    Figure 20: Add test data

    Figure 20: Add test data

Test Execution

  1. Run the test table. To execute all test cases, click the Run button.

    Figure 21: Run Test

    Figure 21: Run Test

  2. OpenL Studio will display the test results.

    Figure 22: Test results window

    Figure 22: Test results window

Failed test cases are marked by the Failed icon.

Passed test cases are marked by the Passed icon.

All test cases passed. Hence, our rule AirTicketsPrice works correctly.

Conclusion

Congratulations — your first rule is created, tested, and ready to be used by the consumer application!

You have created the rule that defines the air ticket price value depending on the city of departure and the city of destination. You have also created a test for your rule to verify the correctness of the rule logic.

We hope that working with OpenL Tablets was interesting and easy for you.