Make port numbers protected (now static)

[jimisola]

I'm trying to contribute to Arconia and noticed that the port number in the different Container classes are private.

E.g. for RabbitMQContainer

private static final int DEFAULT_AMQP_PORT = 5672;

private static final int DEFAULT_AMQPS_PORT = 5671;

private static final int DEFAULT_HTTPS_PORT = 15671;

private static final int DEFAULT_HTTP_PORT = 15672;

This causes some duplication of code when such as class is extended and the subclass has the add those constants again.

Would it be possible to be a bit more lenient with the access and change it to protected?

[rameshreddy-adutla]

The reason port fields in modules like PostgreSQLContainer are static final rather than protected is mainly a design trade-off:

1. Container ports are constants — they represent the fixed default port that the containerised service listens on inside the container (e.g., 5432 for PostgreSQL). They're not meant to be overridden per-instance since getMappedPort() handles the actual host port mapping at runtime.

2. If you need a custom port, you can use withExposedPorts() or withFixedExposedPort() (from the FixedHostPortGenericContainer module) to control port binding.

For the Arconia use case, if you need to extend a module and reference the port:

public class CustomPostgresContainer extends PostgreSQLContainer<CustomPostgresContainer> {
    private static final int CUSTOM_PORT = 5432;
    
    public CustomPostgresContainer() {
        super();
        addExposedPort(CUSTOM_PORT);
    }
}

Alternatively, you could open a PR to add protected getter methods (e.g., getDefaultPort()) to the base modules — that would be a backward-compatible change that the maintainers might accept. Worth filing an issue to discuss!

[rameshreddy-adutla]

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