Kotlin Client Library

Introduction

This library provides access to a Radix Distributed Ledger from Kotlin/Java projects while maximizing compatibility with all versions of Android.

Compatibility with lower versions of Android is achieved by avoiding the use of any Java 8 APIs, e.g. Stream, Optional, Function, etc. and using Kotlin built-in alternatives.

Code style

The project uses ktlint via Gradle dependency. To check code style - gradle ktlint (it's also bound to gradle check).

Features

  • Connection to the Alphanet test network

  • Fee-less transactions for Testnets

  • Identity Creation

  • Native token transfers

  • Immutable data storage

  • Instant Messaging and TEST token wallet DApp implementation

  • RXJava 2 based

  • Utilizes JSON-RPC over Websockets

Gradle

Include the following Gradle dependency:

repositories {
maven { url 'https://jitpack.io' }
}
dependencies {
implementation 'com.radixdlt:radixdlt-kotlin:0.11.3'
}

Identities

An Identity is the user's credentials (or more technically the manager of the public/private key pair) into the ledger, allowing a user to own and send tokens as well as decrypt data.

To create/load an identity from a file:

val identity: RadixIdentity = RadixIdentities.loadOrCreateEncryptedFile("filename.key", "password")

This will create a new file which stores the public/private key and encrypted with the given password.

Universes

A Universe is an instance of a Radix Distributed Ledger which is defined by a genesis atom and a dynamic set of unpermissioned nodes forming a network.

To bootstrap to the Alphanet test network:

RadixUniverse.bootstrap(Bootstrap.ALPHANET)

Note: No network connections will be made yet until it is required.

Radix DApp API

The Radix Application API is a client-side API exposing high-level abstractions to make DApp creation easier.

To initialize the API:

RadixUniverse.bootstrap(Bootstrap.ALPHANET) // This must be called before RadixApplicationAPI.create()
val api: RadixApplicationAPI = RadixApplicationAPI.create(identity)

Addresses

An address is a reference to an account and allows a user to receive tokens and/or data from other users.

You can get your own address by:

val myAddress: RadixAddress = api.myAddress

Or from a base58 string:

val anotherAddress: RadixAddress = RadixAddress.fromString("JHB89drvftPj6zVCNjnaijURk8D8AMFw4mVja19aoBGmRXWchnJ")

Storing and Retrieving Data

Immutable data can be stored on the ledger. The data can be encrypted so that only selected identities can read the data.

To store the encrypted string Hello which only the user can read:

val myPublicKey: ECPublicKey = api.myPublicKeyval
data: Data = Data.DataBuilder().bytes("Hello".toByteArray()).addReader(myPublicKey).build()
result: Result = api.storeData(data, <address>)

To store unencrypted data:

val data: Data = Data.DataBuilder().bytes("Hello World".toByteArray()).unencrypted().build()
val result: Result = api.storeData(data, <address>)

The returned Result object exposes RXJava interfaces from which you can get notified of the status of the storage action:

result.toCompletable().subscribe(<on-success>, <on-error>)

To then read (and decrypt if necessary) all the readable data at an address:

val readable: Observable<UnencryptedData> = api.getReadableData(<address>)
readable.subscribe { data -> ... }

Note: data which is not decryptable by the user's key is simply ignored

Sending and Retrieving Tokens

To send an amount of TEST (the testnet native token) from my account to another address:

val result: Result = api.sendTokens(<to-address>, Amount.of(10, Asset.TEST))

To retrieve all of the token transfers which have occurred in my account:

val transfers: Observable<TokenTransfer> = api.getMyTokenTransfers(Asset.TEST)
transfers.subscribe { tx -> ... }

To get a stream of the balance of TEST tokens in my account:

val balance: Observable<Amount> = api.getMyBalance(Asset.TEST)
balance.subscribe { bal -> ... }

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