GroIMP require Nodes, Node's attributes, and SCOs to be manageable by the persistence manager, to process the save/ load/ query operations.
GroIMP define its own persistence management. To be managed by the GroIMP persistence management, an object need to implements either PersistenceCapable (GroIMP interface), or Serializable (java interface).
Usually the persistence is handled in memory (except when the project is saved), but GroIMP provides a way to integrate it with file persistence (the object is written/loaded from the file). This rely on EmbeddedSharedObject and EmbeddedFileObject.
In GroIMP embedded objects are objects whose persistence is pushed in a file.
EmbeddedSharedObject (ESO) is a class, thus the object needs to extends it. The ESO create on the fly and manage an EmbeddedFileObject (EFO).
The object that extends ESO need to implements the following methods:
public MimeType getMimeType(): to provide the mimetype to use when writing and loading the object (see GroIMP mimetype).public String getExtension(): to provide the file extension (can be an empty string. File extensions are used to make it easier read files but are usually not required).public String getResourceDirectoryName(): Name of the directory in which the file will be stored when the project is saved.public String getObjectType(): java name of the object type (e.g. MyObject.class.getName()).public boolean hasContent(): custom way to check if the object actually needs to be disposed. Can be set to true if it is always the case.Check this tutorial for an example.