https://github.com/americanexpress/maranhao
https://github.com/americanexpress/maranhao
Last synced: about 1 month ago
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- Host: GitHub
- URL: https://github.com/americanexpress/maranhao
- Owner: americanexpress
- License: apache-2.0
- Created: 2019-09-30T17:48:53.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2020-03-20T20:24:40.000Z (over 5 years ago)
- Last Synced: 2025-02-25T03:41:46.606Z (8 months ago)
- Language: Kotlin
- Size: 73.2 KB
- Stars: 0
- Watchers: 7
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE.txt
- Code of conduct: CODE_OF_CONDUCT.md
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README
# Maranhão
Maranhão is a simple framework that aims at speeding up development using Corda DLT. It encapsulates the
boilerplate code, allowing developers to focus on spending time on the business functionality.
The framework breaks up workflow into steps. A simple implementation is also part of the framework. The templatized
imput allows for arbitrary parameters (ideally, a data class) and a number of abstract functions that need to be overridden
```kotlin
@InitiatingFlow
@StartableByRPC
class Initiator(input: Loan) : SimpleMultiStepFlowInitiator(input) {
override fun getListOfSigners(): List = input.signers
override fun getCommandData(): CommandData = ExampleContract.Commands.Request()
override fun getState(): ContractState = ExampleState(input.amount, input.borrower,
input.lender, input.approver,
input.signers)
override fun getStateId(): String = "com.americanexpress.blockchain.example.state.ExampleState"
}
```
#### Simple workflow
To add processing of a new state, override 'initialProcessingStep' as follows:
```kotlin
@InitiatingFlow
@StartableByRPC
class Initiator(input: Loan) : SimpleMultiStepFlowInitiator(input) {
@Suspendable override fun getListOfSigners(): List = listOf(input.lender, input.approver)
@Suspendable override fun getCommandData(): CommandData = ExampleContract.Commands.Request()
@Suspendable override fun getState(): ContractState = ExampleState(input.amount, input.lender, input.approver)
@Suspendable override fun getStateId(): String = "com.americanexpress.blockchain.example.contract.ExampleContract"
override var initialProcessingStep = object: SimpleFlowStep {
override fun execute(ctx: FlowContext) {
val initialState = ctx.sharedData!!.state as ExampleState
ctx.sharedData!!.outputState = initialState.copy(interestRate = 0.05F)
}
}
}
```
### Support for Observer (Witness) node
Provided by the `SimpleAcceptorWithWitness` class. To integrate, take the following steps:
1. Make your acceptor class an extension of `SimpleAcceptorWithWitnessNotifier`
2. Override the `getWitness()` function to return the witness (observer) party
3. Override the `preCall()` function, by implementing all functionality you would normally
do in the overridden `call()` function
4. Mark the witness acceptor with `@InitiatedBy(ReportToWitnessFlow::class)`.
`ReportToWitnessFlow` class belongs to the framework. Sample usage in the
[example](./example/src/main/kotlin/com.americanexpress.blockchain.example/flow/DummyPayoffLoan.kt)
project
### Logging
By default, Maranhao `SimpleMultiStepFlowInitiator` dumps the context `CTX` via default logger.
One can add its own logger, especially if the context contains sensitive data.
### Installation
Clone, then just run the command below. The script will install all required libraries: `./gradlew`
To run a full test, just run: `./gradlew test`
### Where the name (Maranhão) coming from?
Corda is a river in the State of Maranhão, in northeastern Brazil.
We thought it was a cool name for a Corda framework :)
### Authors
* Andras L Ferenczi [andrasfe](https://github.com/andrasfe)
* Pancham Singh
* Nitesh Solanki [nitesh7sid](https://github.com/nitesh7sid)
### Contributing
We welcome Your interest in the American Express Open Source Community on Github.
Any Contributor to any Open Source Project managed by the American Express Open Source Community
must accept and sign an Agreement indicating agreement to the terms below.
Except for the rights granted in this Agreement to American Express and to recipients of software
distributed by American Express, You reserve all right, title, and interest, if any, in and to
Your Contributions. Please fill out the Agreement.
Please feel free to open pull requests and see CONTRIBUTING.md for commit formatting details.
### License
Any contributions made under this project will be governed by the Apache License 2.0.
### Code of Conduct
This project adheres to the American Express Community Guidelines.
By participating, you are expected to honor these guidelines.