> Same for @Serialized and @Dependent, @Index and @Unique > (mainly for collections, but maybe also for maps when keys and values > should share the same setting, or maybe @Serialized and @Dependent should > only cover map values and @Index and @Unique only map keys).
@Serialized is a valid annotation to add but not for what you're suggesting. It should serialise the whole field. If the field is not a container this makes no difference but it does for containers (maps/collections/arrays). If the field is a collection then the whole collection would be serialised with this annotations. This is different to serialising the element only. Best visualised with the case (with an RDBMS) and you want a join table and you have a List and want to serialise the element into one column of the join table. This is where @Element(serialized="true") is used - so the join table has 3 columns ... an FK back to the owner, a List order, and a serialised element. Similarly for Maps ... @Serialized would serialise the map as a whole, whereas @Key(serialized="true")/@Value(serialized="true") would serialise the key/value into any join table. The distinction is important. I'm against the @Index/@Unique on an array/collection/map field implying things regarding indexing the element/key/value. Just doesn't work for maps and I don't like the assumptions that the JPA spec makes. I'm also against having an @Dependent annotation since maps have 2 components, and JPA falls apart on this one too [Its @Cascade applies to Value only, so what happens when a key needs cascading ? undefined!] -- Andy
