ValueComposite
Usage of value objects is one of the most ignored and best return-on-investment the programmer can do. Values are immutable and can be compared by value instead of memory reference. Concurrency is suddenly not an issue, since either the value exists or it doesn't, no need for synchronization. Values are typically very easy to test and very robust to refactoring.
Qi4j defines values as a primary meta type through the ValueComposite, as we think the benefits of values are great. The ValueComposite is very light-weight compared to the EntityComposite, and its value can still be persisted as part of an EntityComposite via a Property.
The characteristics of a ValueComposite compared to other Composite meta types are;
- It is Immutable.
- Its equals/hashCode works on the values of the ValueComposite.
- Can be used as Property types, but will not be indexed and searchable.
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