The package supports entity attributes management. Attributes
can be provided by plugged in providers, The implementation
caches providers results.
Clients Interface
Clients should start at {@link Turbo} class.
It allows to query for attribute values,
to determine their readiness, to write
them down and supports listening on attribute
changes.
Providers Interface
Attribute providers should start at {@link FileAttributeProvider}
implement it and register it using system filesystem at
Services/FileAttributeProviders/Default.
Consistency Note
It may happen that value changes at providers level, however
unnoticed by clients because the value is cached at memory
layer and framework does not check providers in such case.
It may happen only if provider does not have exclusive control
over stored data (e.g. CVS/Entries based provider and extenally
executed cvs).
Solution is that this risk is documented at attribute definition
contract and client of such contract provides to user explicit action
that synchronizes states. Contract should define null
value for invalidation purposes.
Attribute Definition
Both providers and clients must understand
attribute definiton they are using. The attribute
definitions are not covered by this package.