This document discusses the steps to develop a new EMC driver for Eclipse Epsilon. It involves implementing two Eclipse plugins: one for the driver's development tools, and one for the EMC driver itself. The EMC driver implementation requires three classes - a model class implementing IModel, a property getter class implementing IPropertyGetter, and a property setter class implementing IPropertySetter. The model class defines how the model is loaded, stored, and its elements accessed. The property classes retrieve and set property values of the model. The driver is hooked into Epsilon by registering its model type and configuration dialog.

1. Developing a new
EMC Driver for Eclipse Epsilon
Ionut Predoaia

2. Eclipse Epsilon Architecture
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3. EMC Drivers
• the Epsilon Model Connectivity (EMC) layer provides abstraction facilities
over concrete modelling technologies (EMF, XML, Simulink)
• enables Epsilon programs to interact with models conforming to these
technologies in a uniform manner
• EMC makes minimal assumptions about the structure and the organization
of the underlying modelling technologies
• it intentionally refrains from defining classes for concepts such as model
element, type and metamodel
• more resistant to future changes in the implementations of the current
technologies and can also embrace new technologies without changes
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4. Implementation of EMC drivers
Two Eclipse plugins:
➢Implementation of the driver’s Eclipse-based development tools
org.eclipse.epsilon.emc.XX.dt
➢Implementation of the EMC driver
org.eclipse.epsilon.emc.XX
where XX stands for the metamodeling technology used (e.g., EMF, XML, CSV)
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5. Eclipse-based development tools
• provide a dialog to configure models conforming to the new
metamodeling technology
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6. Implementation of Configuration Dialog
• standard implementation (100 lines of code)
Examples: CSV driver, Plain XML driver
• minimal SWT knowledge required
• dialog class extends
❑AbstractCachedModelConfigurationDialog
❑AbstractModelConfigurationDialog
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7. Configuration Dialog class
extends AbstractCachedModelConfigurationDialog
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8. Configuration Dialog class
extends AbstractCachedModelConfigurationDialog
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9. Configuration Dialog class
AbstractModelConfigurationDialog
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10. Configuration Dialog class
AbstractCachedModelConfigurationDialog
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11. Configuration Dialog class
AbstractModelConfigurationDialog
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12. Configuration Dialog class
extends AbstractCachedModelConfigurationDialog
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13. Configuration Dialog class
extends AbstractCachedModelConfigurationDialog
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14. Configuration Dialog class
Storing properties
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15. Configuration Dialog: Exercises
1. Modify the model name
2. Add a new group in the dialog (text field and checkbox)
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16. Implementation of EMC drivers
Two Eclipse plugins:
➢Implementation of the driver’s Eclipse-based development tools
org.eclipse.epsilon.emc.XX.dt
➢Implementation of the EMC driver
org.eclipse.epsilon.emc.XX
where XX stands for the metamodeling technology used (e.g., EMF, XML, CSV)
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17. Implementation of the EMC driver
Three classes are required:
• a class for defining the model
❑ implements IModel
• a Property Getter class for the model
❑ implements IPropertyGetter
• a Property Setter class for the model
❑ implements IPropertySetter
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18. Implementation of the EMC driver
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19. Class for defining the model
Extend/implement one of the following:
• IModel
• Model
• CachedModel<ModelElementType> (recommended)
…
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20. Class for defining the model (CachedModel)
• identify what is a model element in your modelling language:
❑ XML : Element ⟶ CachedModel<Element>
❑ CSV : Map ⟶ CachedModel<Map<String, Object>>
❑ YAML : Entry ⟶ CachedModel<Entry>
• the methods from IModel must be parameterised using the identified
model element type
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21. Class for defining the model
Examples:
• CSV driver
• Plain XML driver
• YAML driver
• Simulink driver
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22. Hook Model to Epsilon
• we need to inform Epsilon that there is a new model type available:
❑ the name of the model type
❑ the class of the new model
❑ the configuration dialog of the new model
❑ an icon for the launch dialog
• use the Extension Point: org.eclipse.epsilon.common.dt.modelType
• added using MANIFEST.MF (Extension tab)
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23. Hook Model to Epsilon
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24. Implementing IModel : load()
• loads the model in memory from storage
• the properties from the Configuration Dialog are
passed in the properties parameter of the load
method
• initializes the required data and parameters
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25. Implementing IModel : loadModel()
• loads in memory the selected model in the Configuration Dialog
• ideally, it should set up a data structure that keeps track of
instantiated model elements
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26. Implementing IModel : disposeModel()
• executes clean-up code for releasing model resources
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27. Implementing IModel : store()
• persists the in-memory representation of the model to a storage location
• the method is executed only when the value of the property Store on disposal is true
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28. Implementing IModel : isLoaded()
• returns true if the model is loaded in memory
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29. Implementing IModel : isModelElement()
• returns true if an instance is a model element
• this is usually done by comparing the type of the instance with the
type of the model element
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30. Types and Kinds
• the type-of relationship appears when a model element is an instance
of a type
• the kind-of relationship appears when the model element is an
instance of a type or any of its sub-types
Examples:
➢ s_{nodeName} for scalar nodes
➢ m_{nodeName} for mapping nodes
➢ l_{nodeName} for list nodes
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31. Implementing IModel : getTypeOf()
• returns the fully-qualified name of the type of a model element
(instance)
• the type represents the class of the model element
• CachedModel<ModelElementType>
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32. Implementing IModel : getTypeNameOf()
• returns the type name of a model element (instance)
• the type name is used for caching purposes
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33. Implementing IModel : getAllTypeNamesOf()
• returns an immutable set over the type name of a single model
element instance
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34. Implementing IModel : getCacheKeyForType()
• the returned string is the type
• used as a key for caching model elements by type
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35. Implementing IModel : hasType()
• returns true if the model supports a type with the specified name
(e.g., s_role, m_city, t_book)
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36. Implementing IModel : isInstantiable()
• returns true if instances of the type can be created
• it is usually based on the method hasType()
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37. Implementing IModel : creating instances
• create a new model element instance of a specific type and return it
• add the created instance to the list of created instances
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38. Implementing IModel : deleting instances
• delete the model element instance from the in-memory
representation of the model
• delete the model element instance from the list of created instances
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39. Implementing IModel : owns()
• returns true if the model element instance is contained within the in-
memory representation of the model or in the list of created instances
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40. Implementing IModel : allContentsFromModel()
• returns the entire content of the model, i.e., all model elements
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41. Implementing IModel : getAllOfTypeFromModel()
• returns all model elements with the specified type
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42. Implementing IModel : getAllOfKindFromModel()
• returns all model elements with the specified kind
• in many cases the kind may be similar to the type, therefore the
method can just call getAllOfTypeFromModel(kind)
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43. Implementing IModel: Exercises
1. Modify the method getAllOfTypeFromModel()
2. Modify the method createInstance()
3. Modify the method deleteElementInModel()
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44. Implementing IModel : getElementById()
• returns a model element by its id
Examples:
➢ CSV – the IDs can be represented with a specific column
➢ XML – the IDs can be represented as an attribute
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45. Implementing IModel : getElementId(), setElementId()
• gets/sets the id of a model element
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46. Implementing IModel : getEnumerationValue()
• used to retrieve an enumeration literal from a specific enumeration
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47. Implementation of the EMC driver
Three classes are required:
• a class for defining the model
❑ implements IModel
• a Property Getter class for the model
❑ implements IPropertyGetter
• a Property Setter class for the model
❑ implements IPropertySetter
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48. Property Getter class
➢ retrieve the value of a property
➢ extend/implement one of the following:
• IPropertyGetter
• AbstractPropertyGetter
• JavaPropertyGetter
…
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49. Property Getter class
Examples:
• CSV driver
• Plain XML driver
• YAML driver
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50. Implementing the Property Getter class
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51. Property Setter class
➢ set the value of a property
➢ extend/implement one of the following:
• IPropertySetter
• AbstractPropertySetter
• JavaPropertySetter
…
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52. Property Setter class
Examples:
• CSV driver
• Plain XML driver
• YAML driver
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53. Implementing the Property Setter class
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54. Property Getter/Setter class: Exercises
1. Add a new property in the Property Getter class
2. Add a new property in the Property Setter class
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55. Summary
➢implementation of the driver’s Eclipse-based development tools
➢implementation of the EMC driver
• a class for defining the model
• a Property Getter class for the model
• a Property Setter class for the model
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