A building block is saved with the usual save command in Eclipse (File/Save), or the save icon in the menu bar, or the key shortcut cmd+S (Mac) / Ctrl+S (Win, Linux).
Double-click the Reactive Blocks project to open the project within the Package Explorer to see how projects and building blocks are stored internally as Eclipse projects. (You may have to disable exclusion of hidden files (.*resources) from the view first.) Here is an example:
Each building block is stored within a separate UML file. The file has the name of the building block (with any spaces removed), followed by the extension “*.uml”.
An additional manifest file describes some properties of each building block. These files are stored in a directory called ”.descriptions” within each project. This directory is usually hidden, and there should be no need to edit this file manually. However, you may want to know about this file once you use a versioning system.
Whenever you save a building block, a backup copy with a time stamp is copied into a folder ”.backups” within the project of the building block. In the preference panel of the editor you may specify how many copies should be kept. (At the moment, there is no automatic recovery for these backups, but you could get your models back by manually renaming the files.)