Joern Huxhorn wrote:
Marking an object instance immutable conveys intent. You can build additional logic on top of the immutability hypothesis. If someone intentionally circumvents immutability, the ensuing problems are theirs, not ours.
That's exactly what I was trying to say in the following paragraph. Using an ImmutableLoggingEvent interface should be sufficient to mark that intent. Casting from ImmutableLoggingEvent to MutableLoggingEvent is similar to using reflection magic.
Only later did I notice that we were in agreement about the consequences of immutability, i.e. intent ~ contract. Sorry for taking your comments out of their context. The distinction you make between MutableLoggingEvent and ImmutableLoggingEvent does not accurately reflect the distinction I am trying to make between LoggingEvent and LoggingEventMemento which is mostly about serialization and only marginally about mutability. Both LoggingEvent and LoggingEventMemento could be made immutable. I added the makeMutable() method to LoggingEventMemento as an afterthought.
Joern.
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