Marker interface extending MessageInterface. Application commands (write operations) implement this.

NamedCommandInterface adds getCommandName(): string to a command. It declares no property: interface properties are always public, so the contract stays method-only and implementors keep control of their storage. NamedCommandTrait implements it with a $commandName property that defaults to the using class name (late-bound, so it reports the concrete command class) and is writable only from inside the class. The distinct name keeps it clear of a command's own $name property.

CommandResultInterface extends both CommandInterface and ResultInterface, adding getCommand(): CommandInterface, so a command result can be treated as a message and re-enter the pipeline. CommandResult is the concrete, final readonly implementation, wrapping the original CommandInterface, a MessageStatus, and the raw result value.

Marker interface extending MessageInterface. Application queries (read operations) implement this.

Mirrors the command result types: QueryResultInterface extends QueryInterface and ResultInterface, adding getQuery(): QueryInterface. QueryResult is the final readonly implementation wrapping the original QueryInterface, a MessageStatus, and the raw result value.

CommandHandlerInterface/QueryHandlerInterface declare no method, so each handler declares the method its wired strategy expects:

See Strategy and Usage Examples.