Storing the model and presenter state pair

When a model is inserted into the document embedding hierarchy, it is asked to create a document component store that will satisfy its needs. It either creates a standard document component store or a specialized one.

Each model and presenter state pair has its own document component store.

Just as the embedded document components form an embedding hierarchy, the document component stores form a corresponding hierarchy.

The basic document component store treats models differently from other persistent data. For models, it allows them to use the storage mechanism directly. The default behavior for a model is to ask the mechanism to create a stream and then use its streaming operators to handle the filing.

For all other persistent data, the store has the storage mechanism create a stream for each persistent data instance that it stores.