av.tob
Annotation Type UseKinComparator

@Retention(value=CLASS)
public @interface UseKinComparator

Used to annotate a KinSet field that a particular Comparator should be used to sort kins in the set.

Note:

1. The specified Comparator implementation is required to produce consistent comparation results regardless of the persistent states changes of the compared Kins. That is, only immutable attributes should be used to perform the comparation. The persistent object ID, the creation time of both the source relation object and the related object are good candidates. And values of some persistent fields, e.g. a Person object's Gender value, can be used if they are guarannteed not to change.
2. Even if the comparator reports that a kin equals to another existing one already in the kin set, adding the new kin to the kin set will not overwrite the existing one. In this case the order of such equal kins is undefined.

The specified class must comply with one or more of the following:

1. Expose a public static final field namely instance, which be type of the specified class, so that this field value is used to construct KinSet objects at runtime.
2. Expose a public static method namely singleton(), which with return type of the specified class, so that this method is invoked to construct KinSet objects at runtime.
3. Expose a public no-arg constructor, so that an instance is created to construct each KinSet object at runtime.

If more of the above is implemented by the specified class, the first met will be used.

This annotation will only take effect when the annotated KinSet field is left uninitialized or explicitly initilized to null by the application defined persistent class. TOB will generate code to initialized KinSet fields for born objects at runtime, regarding this annotation, but after checked null values. So if a KinSet field has already been initialized by the application to a non-null value, it will be left as is.

Author:

Compl

Required Element Summary

Class<? extends Comparator<? extends Kin<?,?>>>

value

Element Detail

value

public abstract Class<? extends Comparator<? extends Kin<?,?>>> value

Returns:

a class implemented the comparator interface for kins

See Also:

UseKinComparator