filter

Accepts or rejects a passed message.

A filter can:

• accept the message (by returning Optional.empty());
• reject the message with Error status, for example, if it fails to pass the validation;
• reject the message with OK status. For example, a scheduled command may not pass a filter;
• reject the message with a business rejection. For example, a command can be rejected if the user who made the request does not have enough permissions in the system. Such rejection is only applicable to commands.

Parameters