tpiekarski / coupon-engine

Prototype for a Coupon-Engine driven by Easy Rules and Spring Expression Language

Coupon Engine Prototype

A prototype for evaluating coupon rules driven by Easy Rules and Spring Expression Language providing a simple CLI for testing and developing.

1. Introduction
2. Prototyped Rules
3. Build
4. Dependencies
5. Usage
6. JSON Input Examples

Introduction

This prototype leverages Easy Rules and Spring Expression language for evaluation of coupon rules defined in JSON files with an easy and expressive way of defining multiple rules. A set of n rules and their options, like a coupon code, a category of products or a minimum cart value are evaluated based upon a cart defined in another JSON file.

The processing is divided into two distinct scopes. The first scope is validation scope, in which the coupon is checked for validity. For example if the provided code is valid or if a coupon is not yet expired. The second scope is application, in which a valid coupon is checked for application to a cart and its items.

Prototyped Rules

Rule	Option	Scope	Description
Category	Name of category	Application	Rule for evaluating if products are from one category
Exclude	Product SKU	Application	Rule to exclude a product SKU
Expiration	Date (YYYY-mm-dd, i.e. 2018-01-01)	Validation	Rule for an expiration date
MinimumCartValue	Minimum Amount (Integer-based price)	Validation	Rule for a minimum cart value
ValidCode	String containing a coupon code	Validation	Rule for evaluation valid coupon codes

Build

mvn package

Dependencies

#	Dependency	Version
1.	Apache Commons IO	2.6
2.	Apache Maven Shade Plugin	3.1.0
3.	Maven Coveralls Plugin	4.3.0
4.	Easy Rules Core	3.0.0
5.	FasterXML Jackson Core	2.9.10.4
6.	Google Guice Inject	4.1.0
7.	Jacoco	0.7.7.201606060606
8.	jUnit	4.12
9.	Pitest	1.2.4
10.	Spring Expression Language	5.0.1

Usage

General system-independent usage

java -jar target/coupon-prototype-0.2.2-shaded.jar --cart examples/cart.json --coupon examples/coupon.json

U*NIX-based systems launcher

./coupon-cli.sh --cart examples/cart.json --coupon examples/coupon.json

Windows-based systems launcher

coupon-cli.bat --cart examples/cart.json --coupon examples/coupon.json

CLI & Parameters

java -jar target/coupon-prototype-0.2.2-shaded.jar --verbose --cart examples/cart.json --coupon examples/coupon.json

Parameter (Long)	Parameter (Short)	Parameter (Windows)	Input	Description
--cart	-c	/C	<cart.json>	JSON file defining a cart
--coupon	-p	/P	<coupon.json>	JSON file defining a coupon
--verbose	-v	/V	-	Optional boolean for silencing easy rules (default is true)

JSON Input Examples

Carts

{
  "value": 100,
  "code": "ABC",
  "items": [
    {
      "sku": "E1000-001",
      "category": "Cheese",
      "price": 50
    },
    {
      "sku": "E1000-010",
      "category": "Cheese",
      "price": 50
    }
  ]
}

Coupons

{
  "discount": 20,
  "type": "percentage",
  "validation": {
      "rules": [
        {
          "rule": "ValidCode",
          "option": "ABC"
        },
        {
          "rule": "MinimumCartValue",
          "option": "35"
        },
        {
          "rule": "Expiration",
          "option": "2018-01-01"
        }
      ],
      "expression": "#ValidCode and #MinimumCartValue and #Expiration"
    },
  "application": {
    "rules": [
      {
        "rule": "Category",
        "option": "Cheese"
      },
      {
        "rule": "Exclude",
        "option": "E1000-020"
      }
    ],
    "expression": "#Category and #Exclude"
  }
}