Saving and Loading Models

Of course you can also save the models you created in Poseidon for UML, but there are a few things that should be mentioned about saving and the format used.

Open Standards Support

Poseidon for UML supports open standards extensively and this is also true for the saving format. UML is standardized by the Object Management Group (OMG). Part of the official UML specification by the OMG is a mechanism for the exchange of models between different tools. This mechanism is based on XML and has special extensions and rules to better represent object-oriented structures as well as metadata. The OMG has specified a concrete application of XML for this purpose that is called the XML Metadata Interchange, or XMI for short. Poseidon for UML makes use of this format. In fact, while most other tools can only import or export XMI, Poseidon for UML uses XMI as the default saving and loading mechanism.

Components Of A .zargo File

The current version of XMI is by itself not sufficient to save all aspects of a UML model. It can be used to transport the names and properties of all model elements, but diagram information (layout, colors, etc.) is not currently included, and therefore this information has to be stored in a different format. Poseidon for UML uses another XML application, called PGML, which is a predecessor to SVG, the Scalable Vector Graphics format, standardized by the W3C.

Finally, some internal information about the model needs to be stored. This is done in yet another XML-based format with the ending .argo. All of the files mentioned are zipped together into just one compressed file with the ending .zargo. This is actually just a regular ZIP file; you can decompress it using any ZIP tool or the Java JAR tool. Usually you don't have to worry about all this. But sometimes, if for example, you want to access the XMI file to exchange it with other tools, you may need to unzip this file and have a closer look inside.

Poseidon 1.5 uses a different XMI format than previous Poseidon versions (up to version 1.4.1). Support for XMI 1.1 and 1.2 as well as UML 1.4 has been added. All .zargo files that were created with older Poseidon versions are converted when necessary, and there is no need to care at all about the different versions. The advantage of the new format comes from the fact that Poseidon is now up-to-date regarding the latest standards. Gentleware also works on better import functionality so that the XMI generated by other CASE tools can be imported smoothly.

To Save a Model:

To Load a Model

You can also import XMI that was created by other UML tools.