java-client-library-guide

description
The developers guide to building on the Radix Test Network with the Java Client Library

Java Client Library

Features

• Connect 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-java: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 tokens and send tokens as well as decrypt data.

To create/load an identity from a file:

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

This will either create or load a file with a 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()
RadixApplicationAPI api = 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:

RadixAddress myAddress = api.getMyAddress();

Or from a base58 string:

RadixAddress anotherAddress = 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:

ECPublicKey myPublicKey = api.getMyPublicKey();
Data data = new DataBuilder()
    .bytes("Hello".getBytes(StandardCharsets.UTF_8))
    .addReader(myPublicKey)
    .build();
Result result = api.storeData(data, <address>);

To store the unencrypted string Hello:

Data data = new DataBuilder()
    .bytes("Hello".getBytes(StandardCharsets.UTF_8))
    .unencrypted()
    .build();
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:

Observable<UnencryptedData> readable = 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:

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

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

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

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

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

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• Mail to hello@radixdlt.com for general enquiries.