hydra-java-client

This is an incubator project, which simplifies working with Hydra from java applications. Hydra is an isomorphic state machine L2 network, which works seemlessly with Cardano.

Hydra

You can access documentation regarding Hydra here: https://hydra.family/head-protocol/. We recommend especially to follow QuickStart on devnet network (https://hydra.family/head-protocol/docs/getting-started/quickstart) and (https://hydra.family/head-protocol/docs/getting-started/demo/with-docker) as well as reading (https://hydra.family/head-protocol/docs/tutorial/using_hydra/using-hydra-part-3)

Hydra API specs: https://hydra.family/head-protocol/api-reference

Hydra State Machine Diagram: https://hydra.family/head-protocol/core-concepts/behavior

Requirements

JDK11
maven3

Building

git clone https://github.com/cardano-foundation/hydra-java-client
cd hydra-java-client
mvn clean install

Dependency

<dependency>
    <groupId>org.cardanofoundation</groupId>
    <artifactId>hydra-java-client</artifactId>
    <version>0.0.2-SNAPSHOT</version>
</dependency>

Compatibility

This client is compatible with Hydra 0.9.0

Example usage

var hydraWSClient = new HydraWSClient(new URI("ws://dev.cf-hydra-voting-poc.metadata.dev.cf-deployments.org:4001"));
hydraWSClient.setHydraQueryEventListener(response -> log.info("response:{}", response));
hydraWSClient.setHydraStateEventListener((prev, now) -> log.info("prev:{}, now:{}", prev, now));
hydraWSClient.connectBlocking(60, TimeUnit.SECONDS);

System.out.println(hydraWSClient.getState()); // HydraState.Idle

hydraWSClient.init(); // fires init request for this client
// at least one client needs to initialise the network

System.out.println(hydraWSClient.getState()); // HydraState.HeadIsInitializing

// when all head participants commit their UTxOs then Hydra head is open, you can also commit empty UTxO but at least one head operator needs to commit // something
hydraWSClient.commit(); // commits empty UTxO

// time passes and then you will be able to see that HydraState becomes open

System.out.println(hydraWSClient.getState()); // HydraState.Open

TODO

publish snapshot on maven
provide interface for Reactive Streams API
JavaDocs and improve documentation
testing

satran004 / hydra-java-client