Skip to main content

Resources and their life cycle

A resource is anything Openflexo can read and, when the technology allows it, write: an Excel workbook, an XML document, an FML model itself. Every resource goes through the same states, whichever technology it belongs to.

Life cycle of a resource

From discovery to save​

A technology adapter scans every registered resource center for the resources it knows how to read, and registers each one it finds. A registered resource is known but not yet read: its data is not in memory. From there:

  • load reads the data into memory — the resource is now loaded;
  • edit changes it in memory — the resource is now modified, with unsaved changes;
  • save writes it back and returns the resource to loaded;
  • unload frees the data in memory and returns the resource to registered, without saving.

Every step notifies the observers of the resource — notifyResourceWillLoad, notifyResourceLoaded, notifyResourceModified, notifyResourceSaved, notifyResourceUnloaded. A resource center, an inspector, or a model that federates the resource is told when it changes state, and can react — this is what lets a virtual model stay in step with a resource edited outside Openflexo.

Where this matters when writing FML​

A property bound to a resource reads and writes through this same life cycle: reading it may load the resource it comes from, and writing it marks that resource modified. Setting up a resource center in practice — a directory or a jar declaring one — is covered in the cookbook.

What you have seen​

A resource is registered by the technology adapter that scans the resource center holding it, then moves between loaded, modified and back to loaded as it is read, edited and saved, and back to registered when unloaded. Every transition notifies the resource's observers.