casper-network / casper-java-sdk

Java library for interacting with a CSPR node

Casper Java SDK

This project implements the SDK to interact with a Casper Node. It wraps the Json-RPC requests and maps the results to Java objects.

Dependencies

• Java 8
• Gradle
• crypto-keys

Build instructions

./gradlew build

Including the library

Using gradle:

implementation 'network.casper:casper-java-sdk:2.4.1'

Using maven:

<dependency>
    <groupId>network.casper</groupId>
    <artifactId>casper-java-sdk</artifactId>
    <version>2.4.1</version>
</dependency>

How to

1. Set-up a connection

casperService = CasperService.usingPeer("127.0.0.1","7777");

2. Query a block

Retrieve block info by a block identifier

Last block

JsonBlockData result = casperService.getBlock();

By height

JsonBlockData result = casperService.getBlock(new HeightBlockIdentifier(1234));

By hash

JsonBlockData blockData = casperService.getBlock(new HashBlockIdentifier("--hash--"));

3. Query transfers

Retrieve block transfers by a block identifier

Last block

TransferData transferData = casperService.getBlockTransfers();

By block height

TransferData transferData = casperService.getBlockTransfers(new HeightBlockIdentifier(1234));

By block hash

TransferData transferData = casperService.getBlockTransfers(new HashBlockIdentifier("--hash--"));

3. Query state root hash

Retrieve the state root hash given the BlockIdentifier

Last block

StateRootHashData stateRootData = casperService.getStateRootHash();

By block height

StateRootHashData stateRootData = casperService.getStateRootHash(new HeightBlockIdentifier(1234));

By block hash

StateRootHashData stateRootData = casperService.getStateRootHash(new HashBlockIdentifier("--hash--"));

4. Query deploy

Get a Deploy from the network

DeployData deployData = casperService.getDeploy("--hash--");

5. Query peers

Get network peers data

PeerData peerData = casperService.getPeerData();

6. Query stored value

Retrieve a stored value from the network

StoredValueData result = casperService.getStateItem("--stateRootHash--", "key", Arrays.asList("The path components starting from the key as base"));

7. Get node status

Return the current status of the node

StatusData status = casperService.getStatus()

8. Get account info

Returns an Account from the network

By block height

AccountData account = casperService.getStateAccountInfo("--publicKey--", new HeightBlockIdentifier(1234));

By block hash

AccountData account = casperService.getStateAccountInfo("--publicKey--", new HashBlockIdentifier("--hash--"));

9. Get auction info

Returns the Auction info for a given block

By block height

AuctionData auction = casperService.getStateAuctionInfo(new HeightBlockIdentifier(1234));

By block hash

AuctionData auction = casperServiceMainnet.getStateAuctionInfo(new HashBlockIdentifier("--hash--"));

10. Get era info

Returns an EraInfo from the network

By block height

EraInfoData eraInfoData = casperService.getEraInfoBySwitchBlock(new HeightBlockIdentifier(1234));

By block hash

EraInfoData eraInfoData = casperService.getEraInfoBySwitchBlock(new HashBlockIdentifier("--hash--"));

11. Deploy

Transfering CSPR

Deploy deploy = CasperDeployService.buildTransferDeploy(from, to,
    BigInteger.valueOf(2500000000L), "casper-test",
    id, BigInteger.valueOf(100000000L), 1L, ttl, new Date(),
    new ArrayList<>());

DeployResult deployResult =  casperServiceTestnet.putDeploy(deploy);

12. Consuming Events

The Java SDK supports the consumption of casper events using the event service API. This API allows the consumer to choose the events to be provided as Pojos or as raw JSON via the EventTarget enum values. Each event stream is consumed individually by providing the required stream (main, sigs, and deploys) using the EventType parameter to the consumeEvents method.

For more information on events see: Monitoring and Consuming Events.

Consuming Raw JSON Event Strings

// Construct an events service
final EventService eventService = EventService.usingPeer(new URI("http://localhost:28101"));

// Consume the main events as raw JSON
eventService.consumeEvents(EventType.MAIN, EventTarget.RAW, 0L, new EventConsumer<String>(){
    
    @Override
    public void accept(final Event<String> event) {
        // Obtain the raw JSON event as a String
        final String json = event.getData();
        // Obtain the optional event ID
        final long id = event.getId().orElse(0L);
    }
});

Consuming Pojo Events

// Construct an events service
final EventService eventService = EventService.usingPeer(new URI("http://localhost:28101"));

// Consume the main events as Casper Java SDK Pojos
eventService.consumeEvents(EventType.MAIN, EventTarget.POJO, 0L, new EventConsumer<EventData>() {
    
    @Override
    public void accept(final Event<EventData> event) {

        switch (event.getDataType()) {

            case BLOCK_ADDED:
                handleBlockAdded(event.getId().get(), ((BlockAdded) event.getData()));
                break;
                
            // And so on...    
        }
    }
});