de.ipcon.tools.ref

Interface DependencyCalculatorI<K,V>

Type Parameters:

K - the type of the cache key

V - the type of the cached value

All Known Implementing Classes:

BOCache

public interface DependencyCalculatorI<K,V>

An interface for caches providing a callback to fetch missing values, and extending the change lister to additional BOs a cached value depends on.

Method Summary

Modifier and Type	Method and Description
long[]	calculateDependencies(K key, V value) This method calculates for a given object the ids of objects, which can invalidate the cached state.

Method Detail

calculateDependencies

long[] calculateDependencies(K key,
                             V value)

This method calculates for a given object the ids of objects, which can invalidate the cached state.

e.g. BO A contains the sum of BO B and BO C. Normal BOChangeEvents only allow looking for explicit changes to A. If this method is implemented and additionally returns the IDs of B and C, then the cache containing A is automatically invalidated, if either B or C changes.

Parameters:

key - the cache key of the object. Guaranteed to be non-null by the cache contract.

value - the currently cached value which might depend on other objects. Can be null (e.g. if caching a "not found" state).

Returns:

an array of longs, which are the IDs of all objects whose changes have an effect on the cached value of the provided object, non-null. Should not contain the id of the value-object itself.