StockExchange sample code

[waynelcw]

A sample for TokenSDK that simulates how a general stock and dividend distribution flow

[waynelcw]

Fixes to be done

• [X] Add general comments to each flow

• [X] Introduce a node "bank" to issue money

• [X] Add more detailed dcomments

• [X] Remove query for UNCONSUMED state as it's done by default

• [X] AnnounceDividend - Change quantity to dividendQuantity

• [X] ClaimDividendReceivable - Use reference state instead of creating a pair of stock states

• [X] GetStockUpdate - Explicitly explaining the usage of ALL_VISIBLE

• [ ] Read me - Make a note about which transaction will the observer receives a copy

• [X] Read me - Add flow excution commands

• [x] Read me - Add flow digrams

• [ ] Read me - Add sequence diagrams