ProvidesMethods

@Provides Methods

When you need code to create an object, use an @Provides method. The method must be defined within a module, and it must have an @Provides annotation. The method's return type is the bound type. Whenever the injector needs an instance of that type, it will invoke the method.

public class BillingModule extends AbstractModule {
  @Override
  protected void configure() {
    ...
  }

  @Provides
  TransactionLog provideTransactionLog() {
    DatabaseTransactionLog transactionLog = new DatabaseTransactionLog();
    transactionLog.setJdbcUrl("jdbc:mysql://localhost/pizza");
    transactionLog.setThreadPoolSize(30);
    return transactionLog;
  }
}

If the @Provides method has a binding annotation like @PayPal or @Named("Checkout"), Salta binds the annotated type. Dependencies can be passed in as parameters to the method. The injector will exercise the bindings for each of these before invoking the method.

  @Provides @PayPal
  CreditCardProcessor providePayPalCreditCardProcessor(
      @Named("PayPal API key") String apiKey) {
    PayPalCreditCardProcessor processor = new PayPalCreditCardProcessor();
    processor.setApiKey(apiKey);
    return processor;
  }

Throwing Exceptions

Salta wraps exceptions thrown by @Provides methods in a SaltaException. For checked exceptions, simply declare them as beeing thrown.