Is it reasonable to generate cache key of collection object without any warnings?

[steadiest]

I saw many people using collection object as a key of ReadThroughSingleCache attached method,
they would be intended to use ReadThroughMultiCache which generates a collection of keys and invokes the multi-get command.

This kind of mistake can lead to unexpected consequences,

• cache key of a big collection will cause communication error by exceeding allowed memcached key length.
• dispersity of cache key increases unexpectedly - cache key will be varied when order or size are changed. And it can make the user think that SSM seems not working well.

It could be good to warn in 2 ways.

• emit warning logs
• or throw InvalidAnnotationException to let them know the key is inappropriate

I wrote this issue after looking at source code below
https://github.com/ragnor/simple-spring-memcached/blob/master/simple-spring-memcached/src/main/java/com/google/code/ssm/aop/support/CacheKeyMethodStoreImpl.java

[ragnor]

Hi,

Thank you for your comment. I agree that usually using ReadThroughSingleCache
on collection of keys is a mistake but not always. To avoid such mistakes
the first solution that you've proposed should be implemented.

I'll add it to the next release.