paulvi / polkadot-java-api

Java APIs around Polkadot and any Substrate-based chain RPC calls. It is dynamically generated based on what the Substrate runtime provides in terms of metadata.Full documentation & examples available.

Polkadot/Substrate Java Api

This library provides a Java wrapper around all the methods exposed by a Polkadot/Subtrate network client and defines all the types exposed by a node.

• packages -- Polkadot/substrate api Java implementation.
• examples -- Demo projects (Gradle).
• examples_runnable -- Demo executable JARs.

Build

Integration test require local polkadot node running (run with polkadot --dev), then
./gradlew build

Alternatively build without running unit tests, but still compiling them
./gradlew build testClasses -x test

JDK

Java 1.8

Based JS code version

The Java version is based on JS commit ff25a85ac20687de241a84e0f3ebab4c2920df7e.

Substrate version

The working substrate version is 1.0.0-41ccb19c-x86_64-macos. Newer substrate may be not supported.

overview

The API is split up into a number of internal packages

• @polkadot/api The API library, providing both Promise and RxJS Observable-based interfaces. This is the main user-facing entry point.
• @polkadot/rpc RPC library.
• @polkadot/type Basic types such as extrinsics and storage.
• @polkadot/types Codecs for all Polkadot primitives.

Document

• See the generated JavaDoc in /doc folder. Or visit the document site
• To generate JavaDoc by yourself, reference gendoc.sh in the root folder
• To understand how the system works, you may reference Substrate and Polkadot Network

Integrate the API into your projects

The project uses Gradle as build tool. You need to install Gradle.

Build the library with Gradle then link to the JAR

1. git clone https://github.com/polkadot-java/api.git
2. gradle build
3. Check the JARs in folder api/build/libs/
4. Add the JARs into your projects (TODO publish on MavenCentral).

Link to the source code directly,

1. git clone https://github.com/polkadot-java/api.git
2. Import the gradle project in folder api to your workspace.
3. Add links or dependencies in the IDE. This differs, please reference to your IDE help (IDEA, Eclipse).

How to build and use sr25591 JNI

1. See polkadot-java/sr25519/readme.md to compile sr25591 library (Rust and C++).
2. See polkadot-java/sr25519/cpp/compile.sh how to compile the JNI shared library.
3. See polkadot-java/sr25519/libs/readme.md how to use the JNI in the Java API.

How to run examples

1. Install substrate local node:
   https://github.com/paritytech/substrate

2. Running the samples:
   There are several runnable samples. To run the samples, go to folder examples_runnable/LastestDate (such as examples_runnable/20190525), then run each shell script.

3. To change the Substrate address, change the endPoint variable in each demo main file.