6. Exporting Models

The XMI File Type

For the interoperability of different UML tools, it is important to be able to export models from a proprietary to a common format. UML defines a standard exchange format for UML models called XMI, which Poseidon for UML uses as the default saving format. This means that every time you save a model it is stored in an XMI file. However, since XMI is a quite wordy xml format and lacks layout information, Poseidon compresses this file, and zips it together with other project information. This file has the name of your project and the ending .zuml. To get to the XMI file, unzip this file with the compression software of your choice.

From version 2.1 on, it is possible to include diagram data in an XMI file by selecting this option during the export process.

Advantages of XMI

Such a standard interchange format has a number of applications. It not only makes sense to be able to replace one tool by another or to exchange models with people using other tools, it also makes sense for chains of tools. The following example well illustrates this value addition:

Some tools are especially well prepared for capturing models designed in cooperative sessions on the white-board. The model is sketched on the white-board, the gestures are tracked and transformed to UML model elements, and a laptop in conjunction with a projector places the newly-created diagram back onto the white-board. This demonstrates and facilitates a creative and cooperative style of working on a model as a team.

Different tools from other vendors are specialized on generating code. They might not even have a graphical user interface, they simply read in a model and produce code for a specific type of application or platform. Such tools can be connected to Poseidon using the XMI format. However, the XMI standard is not implemented equally well among different tools. Poseidon for UML is known to produce one of the cleanest XMI files for its models, and many tools have chosen to support our variant of XMI. However, the interchange might not work with all other tools. The Diagram Interchange standard should alleviate some of these issues once other tools implement the recognized standard.

To Export a Project

  1. Open the File menu and select 'Export Project to XMI'.

  2. The Export Project dialog will open. To the right, select or deselect 'Save with diagramdata'.

  3. Select a location and file name, then click 'Save'.

Figure 9.1. Export a project to XMI

Export a project to XMI