EvmClient

EvmClient is a thin wrapper around web3j which provides some convenient methods to get ERC20 contract details, check balances etc.

Features:

• All returned objects are pure DTO/POJOs without any internal state except the data. They can be easily serialized ( e.g. to JSON) or passed to a cache or session layer.
• All Coins (primary currency of a given chain), token (ERC-20 compatible tokens) and balance objects carry the chain they belong to. This makes it easy to handle multiple chains in one application without risking loosing context.
• web3j (sometimes) throws unclassified checked java.lang.Exception. Those are wrapped in a RuntimeException (net.osslabz.evmclient.EvmClientException) so you don't have the handle/declare them. This is especially useful in an environment where a higher layer handles exceptions in a unified fashion (e.g. Spring).

QuickStart

Maven

<dependency>
    <groupId>net.osslabz</groupId>
    <artifactId>evm-client</artifactId>
    <version>0.0.14</version>
</dependency>

Usage

Connect to Avalanche Mainnet and query information about wrapped AVAX:

    EvmClient evmClient = new EvmClient(Chain.AVALANCHE_MAIN);
    Erc20Token tokenInfo = evmClient.getTokenInfo("0xb31f66aa3c1e785363f0875a1b74e27b85fd66c7"); // wrapped AVAX

returns to following object:

Erc20Token(
  chain=Chain(
    name=Avalanche Network, 
    symbol=AVAX, 
    type=MAIN, 
    id=43114
  ),
  contractAddress=0xb31f66aa3c1e785363f0875a1b74e27b85fd66c7,
  name=Wrapped AVAX,
  symbol=WAVAX,
  decimals=18,
  totalSupply=17216093347349015614973039
)

Logging

This project uses slf4j-api but doesn't package an implementation. This is up to the using application. For the tests logback is backing slf4j as implementation, with a default configuration logging to STOUT.

Compatibility

evm-client targets Java 1.8. It should run fine on Android but this hasn't been tested yet. If you use it on Android please let me know.