[gephi-dev] Import API Refactoring and Improvements

[Mathieu Bastian]

Changes in the current Import API. The aim was to combine improvements for
Yestin's work on Social Media Import and things that we knew we will have to
improve on the API one day. For now importers didn't have the possibility to
define a user interface for settings. It's now possible with an ImporterUI
interface and will be used by Yestin for his work. The social media
importers Yestin is working on has also now a dedicated interface in the
ImportAPI: SpigotImporter.

- Refactoring and improvements in the Import API and SPI. The refactoring
aim is to solve the singleton issue with importers and let users implement
builders interface that create importers instance. Therefore an
ImporterBuilder interface has been created and should be registered with the
@ServiceProvider annotation. The various importers types have been
simplified and leave more choice to the implementations about how the input
is managed. XML and Text file importers has been merged in a FileImporter
interface, working with the java.io.Reader. Utility static methods, for
instance get Document from Reader can now be found in a new
ImportUtils class. The ImportController has been simplified for File import
and now accepts java.io.Reader also. The main improvement on these modules
in the support of UI components for importers. The aim is to let importers
define an ImporterUI implementation to manage settings of these importers.

- Add Spigot support to the ImportAPI and SPI. Like DatabaseImporter, the
SpigotImporter interface is a new type of Importers. Modifications have also
be made to the
ImportController to support spigot import.

Changes were pushed in the trunk.

Mathieu