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79 lines
3.3 KiB
ReStructuredText
79 lines
3.3 KiB
ReStructuredText
.. highlight:: kotlin
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.. raw:: html
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<script type="text/javascript" src="_static/jquery.js"></script>
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<script type="text/javascript" src="_static/codesets.js"></script>
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Using the visualiser
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====================
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In order to assist with understanding of the state model, the repository includes a simple graph visualiser. The
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visualiser is integrated with the unit test framework and the same domain specific language. It is currently very
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early and the diagrams it produces are not especially beautiful. The intention is to improve it in future releases.
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.. image:: visualiser.png
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An example of how to use it can be seen in ``src/test/kotlin/contracts/CommercialPaperTests.kt``.
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Briefly, define a set of transactions in a group using the same DSL that is used in the unit tests. Here's an example
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of a trade lifecycle using the commercial paper contract
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.. container:: codeset
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.. sourcecode:: kotlin
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val group: TransactionGroupDSL<ContractState> = transactionGroupFor() {
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roots {
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transaction(900.DOLLARS.CASH `owned by` ALICE label "alice's $900")
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transaction(someProfits.CASH `owned by` MEGA_CORP_PUBKEY label "some profits")
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}
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// Some CP is issued onto the ledger by MegaCorp.
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transaction("Issuance") {
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output("paper") { PAPER_1 }
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arg(MEGA_CORP_PUBKEY) { CommercialPaper.Commands.Issue() }
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}
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// The CP is sold to alice for her $900, $100 less than the face value. At 10% interest after only 7 days,
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// that sounds a bit too good to be true!
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transaction("Trade") {
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input("paper")
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input("alice's $900")
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output("borrowed $900") { 900.DOLLARS.CASH `owned by` MEGA_CORP_PUBKEY }
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output("alice's paper") { "paper".output `owned by` ALICE }
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arg(ALICE) { Cash.Commands.Move() }
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arg(MEGA_CORP_PUBKEY) { CommercialPaper.Commands.Move() }
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}
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// Time passes, and Alice redeem's her CP for $1000, netting a $100 profit. MegaCorp has received $1200
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// as a single payment from somewhere and uses it to pay Alice off, keeping the remaining $200 as change.
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transaction("Redemption", redemptionTime) {
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input("alice's paper")
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input("some profits")
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output("Alice's profit") { aliceGetsBack.CASH `owned by` ALICE }
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output("Change") { (someProfits - aliceGetsBack).CASH `owned by` MEGA_CORP_PUBKEY }
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if (!destroyPaperAtRedemption)
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output { "paper".output }
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arg(MEGA_CORP_PUBKEY) { Cash.Commands.Move() }
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arg(ALICE) { CommercialPaper.Commands.Redeem() }
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}
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}
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Now you can define a main method in your unit test class that takes the ``TransactionGroupDSL`` object and uses it:
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.. container:: codeset
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.. sourcecode:: kotlin
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CommercialPaperTests().trade().visualise()
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This will open up a window with the following features:
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* The nodes can be dragged around to try and obtain a better layout (an improved layout algorithm will be a future
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feature).
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* States are rendered as circles. Transactions are small blue squares. Commands are small diamonds.
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* Clicking a state will open up a window that shows its fields.
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