axon_es_example.java

import org.axonframework.commandhandling.CommandHandler;
import org.axonframework.commandhandling.model.AggregateIdentifier;
import org.axonframework.eventsourcing.EventSourcingHandler;
import org.axonframework.samples.trader.api.users.*;
import org.axonframework.samples.trader.users.util.DigestUtils;
import org.axonframework.spring.stereotype.Aggregate;

import static org.axonframework.commandhandling.model.AggregateLifecycle.apply;

@Aggregate(repository = "userAggregateRepository")
public class User {

    @AggregateIdentifier
    private UserId userId;
    private String passwordHash;

    public User() {
        // Required by Axon Framework
    }
...
    @CommandHandler
    public boolean handle(AuthenticateUserCommand cmd) {
        boolean success = this.passwordHash.equals(hashOf(cmd.getPassword()));
        if (success) {
            apply(new UserAuthenticatedEvent(userId));
        }
        return success;
    }
    @EventSourcingHandler
    public void on(UserCreatedEvent event) {
        this.userId = event.getUserId();
        this.passwordHash = event.getPassword();
    }
    private String hashOf(char[] password) {
        return DigestUtils.sha1(String.valueOf(password));
    }
}