PolkaJ - Polkadot Java Client

Java client library to use and access API of Polkadot based networks.

Warning

UNDER DEVELOPMENT

Latest Stable Version: 0.3.0
Latest Snapshot Version: 0.4.0-SNAPSHOT

Modules

io.emeraldpay.polkaj:polkaj-scale:0.3.0 - SCALE codec implementation
io.emeraldpay.polkaj:polkaj-scale-types:0.3.0 - SCALE mapping for standard Polkadot types
io.emeraldpay.polkaj:polkaj-schnorrkel:0.3.0 - Schnorrkel for Java
io.emeraldpay.polkaj:polkaj-ss58:0.3.0 - SS58 codec to encode/decode addresses and pubkeys
io.emeraldpay.polkaj:polkaj-common-types:0.3.0 - common types (Address, DotAmount, Hash256, etc)
io.emeraldpay.polkaj:polkaj-json-types:0.3.0 - JSON RPC mapping to Java classes
io.emeraldpay.polkaj:polkaj-api-base:0.3.0 - RPC base classes
io.emeraldpay.polkaj:polkaj-api-http:0.3.0 - JSON RPC HTTP client
io.emeraldpay.polkaj:polkaj-api-ws:0.3.0 - JSON RPC WebSocket client
io.emeraldpay.polkaj:polkaj-tx:0.3.0 - Storage access and Extrinsics

Usage

To use development SNAPSHOT versions you need to install the library into the local Maven repository.

Install into local Maven

gradle install

Using with Gradle

repositories {
   // polkaj public repo
   maven { url  "https://dl.bintray.com/emerald/polkaj" }
   // required for com.github.multiformats:java-multibase library
   maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'io.emeraldpay.polkaj:polkaj-api-http:0.3.0'
}

Documentation

See Documentation in ./docs directory, and a demonstration in ./examples.

Example

Show current finalized block

PolkadotHttpApi client = PolkadotHttpApi.newBuilder().build();
Future<Hash256> hashFuture = client.execute(
        PolkadotApi.commands().getFinalizedHead()
);

Hash256 hash = hashFuture.get();
System.out.println("Current head: " + hash);

Future<BlockResponseJson> blockFuture = client.execute(
        PolkadotApi.commands().getBlock(hash)
);

BlockResponseJson block = blockFuture.get();
System.out.println("Current height: " + block.getBlock().getHeader().getNumber());
System.out.println("State hash: " + block.getBlock().getHeader().getStateRoot());


client.close();

License

The core project code is released under Apache 2.0 license.