Package org.saidone.service.notarization

Class EthereumService

java.lang.Object

org.saidone.component.BaseComponent

org.saidone.service.notarization.AbstractNotarizationService

org.saidone.service.notarization.EthereumService

All Implemented Interfaces:

NotarizationService, org.springframework.beans.factory.Aware, org.springframework.context.ApplicationContextAware

@Service
@ConditionalOnExpression("${application.service.vault.notarization.enabled}.equals(true) and \'${application.service.vault.notarization.impl}\'.equals(\'ethereum\')")
public class EthereumService
extends AbstractNotarizationService

Service responsible for interacting with an Ethereum node to store document hashes.

This component wraps the minimal Web3j interactions required by the application. It creates the Web3j client on startup and uses the provided Credentials to sign transactions that embed document hashes. The bean is instantiated only when the application is configured to use the ethereum implementation of the notarization service.

Constructor Summary

Constructors

Constructor	Description
EthereumService(NodeService nodeService, ContentService contentService, EthereumConfig config)	Creates the service with required dependencies.

Method Summary

Modifier and Type	Method	Description
protected String	getHash(String txHash)	Fetches the hash data stored in the given Ethereum transaction.
void	init()	Initializes the Web3j client and credentials after dependency injection.
protected String	putHash(String nodeId, String hash)	Sends a zero-value transaction containing the given hash as data.
void	stop()	Shuts down the Web3j client before the bean is destroyed.

Methods inherited from class org.saidone.service.notarization.AbstractNotarizationService

checkNotarization, notarizeNode

Methods inherited from class org.saidone.component.BaseComponent

setApplicationContext, shutDown

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EthereumService

public EthereumService(NodeService nodeService,
 ContentService contentService,
 EthereumConfig config)

Creates the service with required dependencies.

Parameters:

nodeService - service used to interact with nodes

contentService - service computing document hashes

config - Ethereum configuration properties

Method Details

init

@PostConstruct
public void init()

Initializes the Web3j client and credentials after dependency injection.

The client is built using the RPC URL from EthereumConfig. If a private key is configured, corresponding Credentials are loaded to allow signed transactions.

Overrides:

init in class BaseComponent

stop

@PreDestroy
public void stop()

Shuts down the Web3j client before the bean is destroyed.

Overrides:

stop in class BaseComponent

getHash

protected String getHash(String txHash)

Fetches the hash data stored in the given Ethereum transaction.

Specified by:

getHash in class AbstractNotarizationService

Parameters:

txHash - the transaction identifier

Returns:

the string stored in the transaction input data

putHash

protected String putHash(String nodeId,
 String hash)

Sends a zero-value transaction containing the given hash as data.

The transaction is signed with the configured credentials and addressed to the account defined in EthereumConfig.

Specified by:

putHash in class AbstractNotarizationService

Parameters:

nodeId - the node identifier

hash - the hash to store on the blockchain

Returns:

the resulting Ethereum transaction hash