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Yenwen Feng edited this page Jun 22, 2018 · 14 revisions

etherspace-java

A Retrofit-like Ethereum client for Android, Java, and Kotlin.

Release Build Status

Introduction

Etherspace is a type-safe Ethereum client to interact with Ethereum Smart Contract.

For example, to access greeter smart contract from ETHEREUM » Create a digital greeter (Slightly modified because we need a setter):

contract greeter {
    /* Define variable greeting of the type string */
    string greeting;
    
    /* This runs when the contract is executed */
    function greeter(string _greeting) public {
        greeting = _greeting;
    }

    /* Main function */
    function greet() constant returns (string) {
        return greeting;
    }

    /* Update greeting */
    function newGreeting(string _greeting) public returns (string) {
        greeting = _greeting;
        return greeting;
    }
}

By defining a Smart Contract interface in Kotlin / Java: (see: Smart Contract Interface)

// Kotlin
interface Greeter {
    @Throws(IOException::class)
    @Send
    fun newGreeting(greeting: String): TransactionHash

    @Throws(IOException::class)
    @Call
    fun greet(): String
}
// Java
public interface Greeter {
    @Send
    TransactionHash newGreeting(String greeting) throws IOException;
    
    @Call
    String greet() throws IOException;
}

Etherspace generates an implementation of Greeter interface.

You can than use greeter to interact with Smart Contract on Ethereum!

// Kotlin
val etherSpace = EtherSpace.build {
    provider = "https://rinkeby.infura.io/" // Or your local node 
    credentials = Credentials(YOUR_PRIVATE_KEY_OR_WALLET)
}
var greeter = etherSpace.create(SMART_CONTRACT_ADDRESS, Greeter::class.java)

val hash = greeter.newGreeting("Hello World")
val receipt = hash.requestTransactionReceipt<TransactionReceipt>()

println(greeter.greet()) // Should be "Hello World"
// Java
EtherSpace etherSpace = new EtherSpace.Builder()
        .provider("https://rinkeby.infura.io/") // Or your local node
        .credentials(new Credentials(YOUR_PRIVATE_KEY_OR_WALLET))
        .build();
Greeter greeter = etherSpace.create(SMART_CONTRACT_ADDRESS, Greeter.class);

TransactionHash hash = greeter.newGreeting("Hello World");
TransactionReceipt receipt = hash.requestTransactionReceipt();

System.out.println(greeter.greet()); // Should be "Hello World"

Example Apps

Declaring Smart Contract Interfaces

Configuration

Download

Release

  • Gradle

    repositories {
  ...
  maven { url 'https://jitpack.io' } // should be the last entry
}

dependencies {
  ...
  // JDK 8
  compile 'cc.etherspace.etherspace-java:etherspace-java:{version}'
  // Android
  implementation 'cc.etherspace.etherspace-java:etherspace-android:{version}'
}

  • Maven

    <repositories>
  <repository>
    <id>jitpack.io</id>
    <url>https://jitpack.io</url>
  </repository>
</repositories>

<!-- JDK 8 -->
<dependency>
  <groupId>cc.etherspace.etherspace-java</groupId>
  <artifactId>etherspace-java</artifactId>
  <version>{version}</version>
</dependency>

<!-- Android -->
<dependency>
  <groupId>cc.etherspace.etherspace-java</groupId>
  <artifactId>etherspace-android</artifactId>
  <version>{version}</version>
</dependency>

Bug reports & feature requests

Please submit issues or pull requests for bugs and features, or contact me at [email protected]. Any feedback is welcome!

Credits

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