ObjectExtender User's Guide and Reference


Creating a model

The first step is to create a model.

  1. Open the Model Browser from the ObjectExtender Tools menu on the Transcript.
  2. Select New Model from the Models menu.
  3. Enter the name for the model: TstUniversity

Specifying storage details for the model

Each model has several storage entities associated with it that relate to how the model is stored in the Envy manager. These entities are the metadata application that is used to store the rules holding the information about how the model is defined.

To hold the metadata for the example model, an application named TstMetadataApp will be created. This should have a prerequisite of VapMetadataApp. The application is created when you save the model as follows:

  1. Select the model, TstUniversity, in the Models view.
  2. Select Save Model from the Models menu.
  3. Enter the application name: TstMetadataApp.


    Figure pgs1appn not displayed.

    Next, you are prompted to enter a class name. This class will hold all of the information about the TstUniversity model within the TstMetadataApp.


    Figure pgs1clsn not displayed.

  4. Enter the class name: TstUniversityModel

Because TstMetadataApp and TstUniversityModel are defined as classes in the Envy manager, they are able to benefit from all of the source management features that Envy provides, that is, they can be versioned to represent a baseline, exported from one manager to another, and included in configuration maps to allow developers to alternate between different consistent states of a model definition together with the Smalltalk classes that implement the model.

Once we have defined the storage entity for TstUniversity, we can save the model by selecting Save Model from the Models menu. This will create an edition of the class TstUniversityModel in the application TstMetadataApp.

Notes:

  1. Loading a model. If another developer loads the application, TstMetadataApp, into their image they will not see the TstUniversity model in their Model Browser by default. The model must be loaded by selecting Load Available Models from the Models menu.

  2. Saving a model. Saving a model will take the information changed in the browser and store it in an edition of the class TstUniversityModel.

  3. Reverting a model. Revert Selected Model (on the Models menu) will revert the model to the last saved definition of the model in the TstUniversityModel class.


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