protected Rule()
{
_builder = new RuleBuilder();
_lhsExpression = new LeftHandSideExpression(_builder);
_rhsExpression = new RightHandSideExpression(_builder);
_definition = new Lazy<IRuleDefinition>(BuildDefinition);
}
private IRuleDefinition BuildRule()
{
//Create rule builder
var builder = new NRules.RuleModel.Builders.RuleBuilder();
builder.Name("TestRule");
//Build conditions
PatternBuilder customerPattern = builder.LeftHandSide().Pattern(typeof (Customer), "customer");
//Can compose expressions at runtime
ParameterExpression customerParameter = customerPattern.Declaration.ToParameterExpression();
var customerCondition = Expression.Lambda(
Expression.Equal(
Expression.Property(customerParameter, "Name"),
Expression.Constant("John Do")),
customerParameter
);
customerPattern.Condition(customerCondition);
PatternBuilder orderPattern = builder.LeftHandSide().Pattern(typeof (Order), "order");
//Can specify expression at compile time
Expression<Func<Order, Customer, bool>> orderCondition1 =
(order, customer) => order.Customer == customer;
Expression<Func<Order, bool>> orderCondition2 =
order => order.Amount > 100.00m;
orderPattern.Condition(orderCondition1);
orderPattern.Condition(orderCondition2);
//Build actions
Expression<Action<IContext, Customer, Order>> action =
(ctx, customer, order) => Console.WriteLine("Customer {0} has an order in amount of ${1}", customer.Name, order.Amount);
builder.RightHandSide().Action(action);
//Build rule model
return builder.Build();
}
private IRuleDefinition ChildCOnessionEligibility()
{
var builder = new NRules.RuleModel.Builders.RuleBuilder();
builder.Name("Child Concession Elgibility Rule");
PatternBuilder passengerPattern = builder.LeftHandSide().Pattern(typeof(Passenger), "passenger");
ParameterExpression passengerParameter = passengerPattern.Declaration.ToParameterExpression();
var passengerCondition = Expression.Lambda(
Expression.LessThan(
Expression.Property(passengerParameter, "Age"),
Expression.Constant(6)),
passengerParameter);
passengerPattern.Condition(passengerCondition);
//Expression<Action<IContext, Passenger>> action =
// (ctx, customer, order) => Console.WriteLine("Customer {0} has an order in amount of ${1}", customer.Name, order.Amount);
//Added
Expression <Action <IContext, Passenger> > action =
(ctx, passenger) => ctx.Insert($"Passenger : {passenger.Name} is eligible for child concession.");
builder.RightHandSide().Action(action);
return(builder.Build());
}
private IRuleDefinition ValidateSrCitizenFlag()
{
var builder = new NRules.RuleModel.Builders.RuleBuilder();
builder.Name("Validate IsConsession flag Rule");
PatternBuilder passengerPattern = builder.LeftHandSide().Pattern(typeof(Passenger), "passenger");
Expression <Func <Passenger, bool> > passengerCondition = (passenger) => passenger.IsSeniorCitizen && passenger.Age < 60;
passengerPattern.Condition(passengerCondition);
Expression <Action <IContext, Passenger> > action =
(ctx, passenger) => ctx.Insert($"Passenger : {passenger.Name} is not eligible for senior citizen concession, since his age is under 60.");
builder.RightHandSide().Action(action);
return(builder.Build());
}
private IRuleDefinition BuildRule()
{
//Create rule builder
var builder = new NRules.RuleModel.Builders.RuleBuilder();
builder.Name("TestRule");
//Build conditions
PatternBuilder customerPattern = builder.LeftHandSide().Pattern(typeof(Customer), "customer");
//Can compose expressions at runtime
ParameterExpression customerParameter = customerPattern.Declaration.ToParameterExpression();
var customerCondition = Expression.Lambda(
Expression.Equal(
Expression.Property(customerParameter, "Name"),
Expression.Constant("John Do")),
customerParameter
);
customerPattern.Condition(customerCondition);
PatternBuilder orderPattern = builder.LeftHandSide().Pattern(typeof(Order), "order");
//Can specify expression at compile time
Expression <Func <Order, Customer, bool> > orderCondition1 =
(order, customer) => order.Customer == customer;
Expression <Func <Order, bool> > orderCondition2 =
order => order.Amount > 100.00m;
orderPattern.Condition(orderCondition1);
orderPattern.Condition(orderCondition2);
//Build actions
Expression <Action <IContext, Customer, Order> > action =
(ctx, customer, order) => Console.WriteLine("Customer {0} has an order in amount of ${1}", customer.Name, order.Amount);
builder.RightHandSide().Action(action);
//Build rule model
return(builder.Build());
}
public RightHandSideExpression(RuleBuilder builder)
{
_builder = builder;
}