Alan Gutierrez

At the outset, Strata was developed for use with in memory and file backed implementations of tiers.

When in memory, branches and the objects can be stored in arrays. The default implementation uses ArrayList classes to store objects.

When file backed, their are two types of objects that can be stored, variable length objects and fixed length objects. Objects can be stored within the tiers or by reference.

When file backed, tiers are softly or weakly referenced, so that they can be collected. Thus, they can act as caches of the objects they reference.

Storing by refernece means storing an address. Whether or not the object is stored in the tier, or by reference outside the tier, the object needs to be in memory for comparisons, for traversal at both the leaf and the inner tier.

By reference storage can keep the object within the in memory tier, or it can perform a look up of the referenced object. The object is an simple object, like a string, it might be easier to keep it in the memory tier, as part of an address, object pair. If it is a complicated object, it can load the object through a caching mechanism.