Walkthrough: Hello World

This walkthrough presents the following fundamental procedures for creating a business rule application with ILOG Rules for .NET.

In this walkthrough, you create a console application that uses a very simple business rule to display a message in a command window.

Creating a New Solution

You develop business rule applications for the .NET environment within a Visual Studio solution.

To create a new solution

Setting up the Business Object Model

The business object model defines the business domain: the things of interest to the business, and a vocabulary for writing rules about them. The vocabulary of the business rules is implemented as annotations to the types in the business object model.

To set up the business object model you:

To define the class library project

using System;
namespace ClassLibrary1{  
  // Class to print a message
  public class Message
  {
    // Prints a message to the console
    public void PrintMessage(string msg)
    {
      Console.WriteLine(msg);
    }
  }
}
Imports System
' Class to print a message
Public Class Message
    ' Prints a message to the console
    Public Sub PrintMessage(ByVal msg As String)
        Console.WriteLine(msg)
    End Sub
End Class

To import the class library into the Business Object Model View

To annotate the business object model

Defining the Business Logic

The business logic of an application is the part that implements the policies of the business. For example, the following is a policy that could be part of the business logic of an application that manages company's relationship with its customers: clients in the Gold service program are upgraded to the Platinum service program after they have renewed their annual subscription five times.

In ILOG Rules for .NET you implement the business logic of an application using business rules. To define the business logic for this business rule application you:

To define the rule project

To write the business rule

The completed rule reads as follows:

Defining the Application Logic

The application logic of an application is the part that performs tasks such as database management, and handling interactions with users. In a business rule application, the application logic includes the part of the application that embeds the rule engine, which executes business rules. Using a rule engine enables you to manage the business logic with processes external to the application.

To define the application logic you:

To define the application project

To implement the application logic

using System;
using System.IO;
using ILOG.Rules;
using ClassLibrary1;
namespace ConsoleApplication1{  
  public class RuleExecuter{    
    public static void Main(){      
      // Create a rule engine in which to execute the ruleset.
      RuleEngine engine = new RuleEngine();
 
      // Create the message object which is the subject of the 
      // rules in the ruleset.
      Message hello = new Message();
 
      // Load the ruleset into the rule engine.
      // The ruleset is generated when you build the rule project.
      engine.RuleSet = new BusinessRules1(); 
 
      // Add the object to the rule engine's working memory.
      engine.Assert(hello);
 
      // Execute the ruleset.
      // The rule engine evaluates the conditions in the ruleset 
      // using the objects in the working memory. The rule 
      // engine initiates the actions of the rules whose 
      // conditions are true. 
      engine.Execute();
 
      //Get the user's input to quit the application.
      Console.WriteLine();
      Console.WriteLine("To exit, press ENTER.");
      Console.In.ReadLine();
    }  
  }
}
Imports System
Imports System.IO
Imports ClassLibrary1
Imports ILOG.Rules
Module Module1
 
    Sub Main()
        ' Create a rule engine in which to execute the ruleset.
        Dim engine As New RuleEngine
        ' Load the ruleset into the rule engine.
        ' The ruleset is generated when you build the rule project.
        engine.RuleSet = New BusinessRules1
 
        ' Create the message object which is the subject of the 
        ' rules in the ruleset.
        Dim hello As New Message
 
        ' Add the object to the rule engine's working memory.
        engine.Assert(hello)
 
        ' Execute the ruleset.
        ' The rule engine evaluates the conditions in the ruleset 
        ' using the objects in the working memory. The rule 
        ' engine initiates the actions of the rules whose 
        ' conditions are true. 
        engine.Execute()
 
        ' Get the user's input to quit the application.
        Console.WriteLine()
        Console.WriteLine("Press ENTER to exit.")
        Console.In.ReadLine()
    End Sub
 
End Module

Running the Business Rule Application

You can test the business rule application within Visual Studio.

To run the business rule application