HW10 Composer: Top-up gym membership

Create a Business Network Archive (BNA) with the appropriate models, transactions, and access constraints that fulfill the requirements below. The BNA must have an initial transaction (setupHomework) that sets up a ledger state, where the fulfillment of each requirement can be demonstrated (assuming that the ledger is empty before the call of the initial transaction). Transactions that would dynamically add participants or assets are not needed, unless noted explicitly under the requirements, except the initializer transaction.

Please test your solution on Composer Playground before submission.

For every Participant and Asset type, the unique identifier must be a non-optional String field with the name id. The value of the field must conform to the following format: <TYPENAME>_<COUNTER>. For example, if we have a Participant type named User, then the id of the first created user must be USER_0, the id of the second user must be USER_1, etc.

Problem statement

Implement a BNA for top-up gym membership management.

• There should be at least two participant types: Gym and Member.
• Each Member has a name (non-unique), an account balance and a Gym associated.
• Each Gym has a name and an address and can request a payment from an associated user.
• Each Member can:
  • join a gym.
  • quit a gym.
  • accept a payment request from a gym, which removes the specified amount from the member's account balance.
  • reject a payment request from a gym.

Additional requirements:

• The initializer transaction should set up a gym and at least 2 users (one who's a member and one who's not).
• Transactions that create users or create gyms are not required.
• Users can only be part of one gym at a time.
• Negative balances are not possible, transactions that'd create such a state should be rejected.

Example scenario

Alice and Bob live near "Claire's Gym." Bob has an account balance of 10 units. Alice is an active member, but Bob isn't. Bob joins the gym, while Alice quits. Claire's Gym requests payment of 1 unit from Bob. Bob accepts the request, resulting in an account balance of 9.

Transactions

• joinGym
• quitGym
• requestPayment
• acceptPayment
• rejectPayment