Create Policies

Implement authorization and business policy rules.

Goal

Create policy rules that enforce authorization and business constraints.

Prerequisites

JD.Domain.Rules package installed
Understanding of validators

Steps

1. Authorization Policy

var rules = new RuleSetBuilder<Order>("Default")
    .Policy("CanCancel", (o, ctx) => 
        o.Status == OrderStatus.Pending && 
        o.CustomerId == ctx.User.Id)
    .WithMessage("You can only cancel pending orders you own")
    .Build();

2. Business Constraint Policy

.Policy("CanPlaceOrder", (c, ctx) =>
    c.IsActive && 
    c.CreditLimit > 0 &&
    !c.HasOverduePayments)
.WithMessage("Customer cannot place orders due to account status")

3. Time-Based Policy

.Policy("WithinBusinessHours", (o, ctx) =>
{
    var now = DateTime.Now;
    return now.Hour >= 9 && now.Hour < 17;
})
.WithMessage("Orders can only be placed during business hours (9 AM - 5 PM)")

Result

Policies enable fine-grained authorization and business constraints that go beyond simple validation.

Next Steps

Create Derivations - Computed properties
Compose Rules - Combine policies

Table of Contents