Collection fast cloners and non-cloned objects

[GoogleCodeExporter]

The fast cloners for Sets and Lists should check for a null response from 
cloner.cloneInternal() before attempting to add to the collection as it's 
possible that null would be returned due to ignoredInstances or ignored classes.

The behavior for a Map is a bit more questionable-- but again would think that 
storing a null value for a key would not be the expected result. In addition, 
it's possible the key itself would not be cloned.

Original issue reported on code.google.com by jklap...@gmail.com on 22 May 2014 at 4:43

[GoogleCodeExporter]

hmm, but what would happen if cloneInternal() returns null? If we don't add the 
item, the cloned list will contain less items than the original

Original comment by kostas.k...@googlemail.com on 21 Jun 2014 at 8:42

[GoogleCodeExporter]

It would. But adding null is likely going to cause more issues then a different 
sized collection. If an object was set up to not be cloned and set to null- and 
since that is behavior explicitly set up I would think the cloner user would 
expect the collection to be smaller.

Original comment by jklap...@gmail.com on 21 Jun 2014 at 9:06

[GoogleCodeExporter]

maybe it is worth filtering out nulls and see how it goes. Seems to me to be a 
bad practice if an instance in a list is configured to be null-ed instead of 
cloned. But if it is so, maybe it is better to filter it out.

Original comment by kostas.k...@googlemail.com on 22 Jun 2014 at 4:45