Inventory

CJ Powered

Sample application for learning object-oriented programming and test-driven design.

The Problem

We are Ace Dry Goods, an Internet store selling packaged foods that store well and taste great. Unfortunately, we keep running out of the stuff we sell.

We need to build an inventory management system right away. Some company managers got together and fleshed out the inventory rules. Our ordering system developers came up with a Java interface, InventoryManager that will give them all they need to place orders each day as long as we implement it according to the rules. They also gave us an interface to the database they've been using to manually track items and levels, InventoryDatabase.

Some of the rules involve information from the marketing department, including information about items on sale and seasons. Their developers put together a Java interface MarketingInfo we will use to integrate with them.

Before you got here, the ordering department and marketing department developers put together a skeleton of the application, a classs called AceInventoryManager. Good thing you're here, though; they need to get back to their own development projects as quickly as possible.

Use the other departments' offerings as much as you need. If you can show where any of those interfaces are insufficient, don't hesitate to ask for interface changes. They will review any requests and enhance the interfaces if necessary.

How to Proceed

0. Clone this repo and get your development environment working. You will know it's all working when you can run the existing unit test suite.
   • you'll need a Java 8 (aka JDK 1.8) SDK
   • you'll probably want an IDE, http://eclipse.org has a good one, just the plain Java IDE is all you need
   • you should have Maven, too: http://maven.apache.org .
1. Bonus: have travis-ci.org automatically build and test your clone
   • sign up to travis-ci.org if you haven't already
   • activate your repository on the Travis-CI website
   • replace the badge in this readme
2. Start working on the rules as if they are new features, one-by-one.
3. You may be advised of new rules or changes to the rules as you progress.

Tips for Success

• Focus on one feature at a time. Don't worry about any feature except for the one you are working on
• Practice red-green-refactor. Write a failing test, get it to pass, commit the code, refactor if you like, commit the code. Never refactor when you are not passing
• Don't forget to test your edge cases. Each feature may require several unit tests
• Only write code that is necessary to pass tests. That way you ensure your tests cover a high proportion of your code
• Don't let requirements changes throw you. Keep focused on the current feature, no matter how the requirements change. Keep working on features in priority order even if that priority changes
• If requirements are incomplete or in conflict, your teacher will act as the product owner and help clarify

Technical Notes and Contracts

• you deliver software through progressive enhancements to the AceInventoryManager class's #getOrders(LocalDate) method.
• Note that AceInventoryManager implements the InventoryManager interface. You can't change that interface without agreement with the ordering department.
• you are free to implement the Item interface as needed for your enhancements. The ordering department will adjust their own database implementation to ensure your Item instance data is returned when needed.
• Item equality is outside your scope. The ordering department defines item equality via the standard Java #equals(Object) method. You must assume that two Item instances are equal if and only if they are the exact same instance. In other words, two items, created by two different construction calls are, by definition, not equal even if they contain the same instance data

The Business Rules

Here is the company's best shot at the inventory rules you should implement. As mentioned, they are sure to discover other rules or even change their minds as you give them more and more working code.

These are in priority order. Unless it is blocked by something else, you should always work on the highest priority item first.

0. For each item we stock, order enough to bring the quantity on hand to its specified inventory level
1. When an item goes on sale, keep an additional 20 units on hand
2. For seasonal items, keep double the normal inventory on hand during the high-demand season. Each seasonal item has one high-demand season.
3. When the required inventory level is above normal due to a sale, season, or other reason, use the highest calculated level. In other words, modifiers do not stack
4. Some items can only be ordered on the first day of the month, do not issue any orders for those items except on the first of the month
5. Some items can only be ordered in packages containing multiple units. we can stock more than the normal inventory level for those items if necessary