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: 0.5.0-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 = PolkadotApi.newBuilder()
    .rpcCallAdapter(JavaHttpAdapter.newBuilder().build())
    .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.

Examples and docs are published under CC0 license + additionally Apache 2.0 for code parts in the examples.