Hiero Enterprise Java

This project provides Java modules to interact with a Hiero network in a Java Enterprise application. The project provides integrations to Spring Boot or Eclipse Microprofile (like Quarkus) for interacting with Hiero. This module is based on the Hedera Java SDK(will be migrated to Hiero Java SDK in near future) and provides a set of managed services to interact with a Hiero network.

Note

The repo is currently transformed to be compatible with the vendor neutral Hiero project. Hedera is 100% compatible with Hiero and the transformation is just a renaming of the packages, classes, documentation, and so on. The transformation is still in progress and not all is renamed yet.

Spring Boot support

To use this module, you need to add the following dependency to your project:

<dependency>
    <groupId>com.open-elements.hiero</groupId>
    <artifactId>hiero-spring</artifactId>
    <version>VERSION</version> 
</dependency>

Configuration

To configure the module, you need to add the following properties to your application.properties file:

spring.hiero.accountId=0.0.53854625
spring.hiero.privateKey=2130020100312346052b8104400304220420c236508c429395a8180b1230f436d389adc5afaa9145456783b57b2045c6cc37
spring.hiero.network=hedera-testnet

The spring.hiero.network property defines the network that is used to interact with the Hiero network. In the given example, the Hedera testnet network is used. Hedera is based on Hiero and therefore the testnet can be used to interact with a Hiero network. The account information (accountId, privateKey) can all be found at the Hedera portal for a testnet or previewnet account. Today only the "DER Encoded Private Key" of the "ECDSA" key type is supported for the spring.hiero.privateKey property.

The 2 properties spring.hiero.accountId and spring.hiero.privateKey define the "operator account". The operator account is used as the account that sends all transactions against the Hiero network.

Usage

To use the module, you need to add the @EnableHiero annotation to your Spring Boot application class.

import com.open.elements.spring.hiero.EnableHiero;

@SpringBootApplication
@EnableHiero
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Once that is done you can for example autowire the FileClient class and call the methods to interact with a Hiero network.

@Service
public class HieroAccountService {

    @Autowired
    private FileClient fileClient;

    public String readFile(String id) {
        FileId fileId = FileId.of(id);
        byte[] content = fileClient.readFile(fileId);
        return new String(content);
    }
}

All APIs of the client are synchronous and return the result of the operation. For asynchronous operations, you can easily wrap calls by use the @Async annotation of spring.

Hiero Spring Sample

A sample application that uses the Hiero Spring module can be found in the hiero-spring-sample module. The sample application is a simple Spring Boot application that reads has a REST endpoint at localhost:8080/ and shows the hbar balance of the account 0.0.100 on the Hedera testnet. To use the application, you need to have created a Hedera testnet account at the Hedera portal. The account information can be added to the application.properties file in the hedera-spring-sample module:

spring.hiero.accountId=0.0.3447271
spring.hiero.privateKey=2130020100312346052b8104400304220420c236508c429395a8180b1230f436d389adc5afaa9145456783b57b2045c6cc37

Alternatively, you can provide the account information as environment variables:

export HEDERA_ACCOUNT_ID=0.0.3447271
export HEDERA_PRIVATE_KEY=2130020100312346052b8104400304220420c236508c429395a8180b1230f436d389adc5afaa9145456783b57b2045c6cc37

Microservice support

The support for Microprofile is still in development and can not be used yet.

Managed services

The module provides a set of managed services that can be used to interact with a Hiero network. The following services are available in spring and microprofile:

• com.openelements.hiero.base.AccountClient: to interact with accounts
• com.openelements.hiero.base.FileClient: to interact with files
• com.openelements.hiero.base.SmartContractClient: to interact with smart contracts
• com.openelements.hiero.base.ContractVerificationClient: to verify smart contracts
• com.openelements.hiero.base.NftClient: to interact with NFTs
• com.openelements.hiero.base.NftRepository: to query NFTs

Next to that the following low-level services are available:

• com.openelements.hiero.base.protocol.ProtocolLayerClient: to interact with the Hiero protocol layer
• com.openelements.hiero.base.mirrornode.MirrorNodeClient: to query the Hiero mirror node

Built the project

The project is based on Maven. To build the project, you can use the following command:

./mvnw verify

The tests in the project are working against any Hiero network. You need to provide the account id and the private key of an account that is used to run the tests. If no account is provided, the tests will fail. The most easy way to run the tests is to use the Hedera testnet network. To run the tests, you need to provide the account id and the "DER Encoded Private Key" of the "ECDSA" testnet account. That information can be provided as environemt variables:

export HEDERA_ACCOUNT_ID=0.0.3447271
export HEDERA_PRIVATE_KEY=2130020100312346052b8104400304220420c236508c429395a8180b1230f436d389adc5afaa9145456783b57b2045c6cc37
export HEDERA_NETWORK=testnet

As an alternative you can define the information in a .env file in each sub-module that contains tests. The file should look like this:

spring.hiero.accountId=0.0.3447271
spring.hiero.privateKey=2130020100312346052b8104400304220420c236508c429395a8180b1230f436d389adc5afaa9145456783b57b2045c6cc37

Create a release

The project is using the JReleaser Maven plugin to create and publish releases. To use the plugin, you need to provide the following environment variables:

JRELEASER_GITHUB_TOKEN=your_secret_github_token
JRELEASER_GPG_SECRET_KEY=your_secret_key
JRELEASER_GPG_PASSPHRASE=your_secret_passphrase
JRELEASER_GPG_PUBLIC_KEY=yout_public_key
JRELEASER_NEXUS2_MAVEN_CENTRAL_USERNAME=your_maven_central_username
JRELEASER_NEXUS2_MAVEN_CENTRAL_TOKEN=your_secret_maven_central_token

How that environment variables are defined can be found in the JReleaser documentation and this blog post.

On a unix based system the environment variables can be defined in the .env file in the root of the project.

Once that is done you can use the release.sh script in the root folder of the repos to create a release:

./release 0.1.0 0.2.0-SNAPSHOT

This will create a release on GitHub and publish the artifacts to Maven Central. As you can see 2 params are passed to the release.sh script, The first param defines the version for the release and the second param defines the version after the release. In the given example the project has defined version 0.1.0-SNAPSHOT before the script is executed. The execution will release the current code under version 0.1.0 and later switch the version to 0.2.0-SNAPSHOT and commit it.

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.