andreschaffer/event-sourcing-cqrs-examples

package bankservice.domain.model.account;

import static java.math.BigDecimal.ZERO;
import static java.time.ZoneOffset.UTC;
import static java.time.ZonedDateTime.now;

import bankservice.domain.model.Aggregate;
import bankservice.domain.model.Event;
import java.math.BigDecimal;
import java.util.List;
import java.util.UUID;

public class Account extends Aggregate {

  private BigDecimal balance;
  private UUID clientId;

  public Account(UUID id, UUID clientId) {
    super(id);
    AccountOpenedEvent accountOpenedEvent = new AccountOpenedEvent(
        id, now(UTC), getNextVersion(), clientId, ZERO);
    applyNewEvent(accountOpenedEvent);
  }

  public Account(UUID id, List<Event> eventStream) {
    super(id, eventStream);
  }

  public void deposit(BigDecimal amount) {
    BigDecimal newBalance = balance.add(amount);
    AccountDepositedEvent accountDepositedEvent = new AccountDepositedEvent(
        getId(), now(UTC), getNextVersion(), amount, newBalance);
    applyNewEvent(accountDepositedEvent);
  }

  public void withdraw(BigDecimal amount) {
    BigDecimal newBalance = balance.subtract(amount);
    if (newBalance.signum() == -1) {
      throw new NonSufficientFundsException(getId(), balance, amount);
    }
    AccountWithdrawnEvent accountWithdrawnEvent = new AccountWithdrawnEvent(
        getId(), now(UTC), getNextVersion(), amount, newBalance);
    applyNewEvent(accountWithdrawnEvent);
  }

  @SuppressWarnings("unused")
  private void apply(AccountOpenedEvent event) {
    clientId = event.getClientId();
    balance = event.getBalance();
  }

  @SuppressWarnings("unused")
  private void apply(AccountDepositedEvent event) {
    balance = event.getBalance();
  }

  @SuppressWarnings("unused")
  private void apply(AccountWithdrawnEvent event) {
    balance = event.getBalance();
  }

  public BigDecimal getBalance() {
    return balance;
  }

  public UUID getClientId() {
    return clientId;
  }
}