SignumJ

Signum Java Development Framework

Including in your project

• Maven:

<repositories>
	<repository>
	    <id>jitpack.io</id>
	    <url>https://jitpack.io</url>
	</repository>
</repositories>
<dependencies>
    <dependency>
	    <groupId>com.github.signum-network</groupId>
	    <artifactId>signumj</artifactId>
	    <version>v1.3.1</version>
	</dependency>
</dependencies>

• Gradle:

repositories {
	maven { url 'https://jitpack.io' }
}
dependencies {
	implementation 'com.github.signum-network:signumj:v1.3.1'
}

Usage

• Commonly used Signum objects / entities / helper classes can be found in the entity package.

• For locally-performed cryptographic operations such as encrypting/decrypting, signing/verifying, etc please see the SignumCrypto interface (Use SignumCrypto.getInstance() to obtain a singleton instance)

• For Singum Node API calls such as making transactions and looking at blocks/accounts/transactions, please see the NodeService interface. (Use NodeService.getInstance("http://nodeAddress.com:8125") to obtain an instance.)

The NodeService wraps the returned values in RxJava Singles. You can create your own SchedulerAssigner to automatically make all returned values subscribe on the specified schedulers. If you don't want to use RxJava, call toFuture() on any Single.

GSON is used for JSON serialization/deserialization. To obtain a GsonBuilder customized to serialize/deserialize the entities, call SignumUtils.buildGson().

SignumJ badge

If you use SignumJ on your project, please consider using one the badges available on the style guide.

Examples

Please see the examples folder. Bellow a simple example on how to send a transaction and sign it locally.

import signumj.Constants;
import signumj.crypto.SignumCrypto;
import signumj.entity.SignumAddress;
import signumj.entity.SignumValue;
import signumj.service.NodeService;

/**
 * Example which sends 1 SIGNA to another account with a fee of 0.1 SIGNA.
 * 
 * Performs the cryptographic signature locally so does not send the passphrase
 * to over the wire.
 * 
 */
public class SendTransactionBlockingGet {

	public static void main(String[] args) {
        NodeService node = NodeService.getInstance(Constants.HTTP_NODE_EUROPE2);

        String passphrase = "YOUR SENDING ACCOUNT PASSPHRASE, USED TO SIGN MESSAGES LOCALLY";
        
        SignumAddress recipient = SignumAddress.fromRs("S-JJQS-MMA4-GHB4-4ZNZU");
        SignumValue amountToSend = SignumValue.fromSigna(1);
        SignumValue fee = SignumValue.fromSigna(0.1);
        int deadline = 1440; // deadline in minutes before this transaction becomes invalid

        // Generate the transaction without signing it
        byte[] unsignedTransactionBytes = node.generateTransaction(recipient,
        		SignumCrypto.getInstance().getPublicKey(passphrase), amountToSend, fee, deadline, null).blockingGet();
        
        // Locally sign the transaction using our passphrase
        byte[] signedTransactionBytes = SignumCrypto.getInstance().signTransaction(passphrase, unsignedTransactionBytes);
        
        // Broadcast the transaction through the node, still not sending it any sensitive information.
        node.broadcastTransaction(signedTransactionBytes).blockingGet();
    }
}