doc/articles/reflective-emf-tutorial/content.wiki

=Reflective EMF Tutorial=
 
This tutorial demonstrates how to create an EMF Ecore metamodel and a sample model that conforms to it reflectively (i.e. without generating any code).

==Prerequisites==
 
To go through this tutorial you need to first install the Eclipse Modeling Distribution, Epsilon and Emfatic. Installation instructions are available [[../../../download|here]].

==Create a new project==
 
Go to '''File->New->Other...''' and select '''General->Project'''. Type '''library''' as the project name:

[[image:new-project.jpg]]

==Create library.emf==
 
Go to '''File->New->Other...''' and select '''File'''. Type '''library.emf''' as the file name:

[[image:create-emfatic.jpg]]

This is where we'll specify our Ecore metamodel using the Emfatic textual syntax

==Add content to library.emf==
 
Now '''library.emf''' should be open and you can copy-paste the following text into it (our sample metamodel) and save.

{{{emf
@namespace(uri="library", prefix="")
package library;

class Library {
   val Writer[*] writers;
   val Book[*] books;
}

class Writer {
   attr String name;
   ref Book[*] books;
}

class Book {
   attr String title;
   attr int pages = 100;
   attr BookCategory category;
}

enum BookCategory {
   Mystery;
   ScienceFiction;
   Biography;
}
}}}

Now your '''library.emf''' editor should look like this:

[[image:emfatic-editor.png]]

==Generate library.ecore from library.emf==
 
The next step is to generate a proper XMI-based Ecore metamodel from the Emfatic textual representation. To do this, you can right-click '''library.emf''' and select '''Generate Ecore model''' as shown below:

[[image:generate-ecore.png]]

Once you've done this you should have a new file called '''library.ecore''' sitting next to your '''library.emf'''. Congratulations! You're half-way there!

'''Tip:''' If at some point you change '''library.emf''', you need to repeat this step in order to update '''library.ecore'''.

==Register library.ecore==
 
The next step is to let EMF know of the existence of your newly created '''library.ecore''' metamodel. To do this, right-click '''library.ecore''' and select '''Register EPackages''' as shown below:

[[image:register-epackages.png]]

==Create a model that conforms to library.ecore==
 
Now we're ready to create models that conform to our new Ecore metamodel! To create a model, go to '''File->New->Other...''' and select '''EMF Model''' as shown below:

[[image:create-emf-model.jpg]]

Click '''Next''' and set the name of the model to '''mylibrary.model''':

[[image:set-emf-model-name.jpg]]

Then hit the '''Browse...''' button next to the '''Metamodel URI''' field and select '''library''' in the list that pops up:

[[image:set-emf-model-namespace.jpg]]

Finally, select '''Library''' from the '''Root instance type''' combo box and hit '''Finish''':

[[image:set-emf-model-root.jpg]]

Now '''mylibrary.model''' should be open in a tree-based editor:

[[image:empty-model.jpg]]

==Add content to mylibrary.model==
 
To create a new '''Book''' under the library, you can right-click it and select '''New Child->Books Book'''

[[image:create-book.png]]

To set the title of the new book, you can right-click it and select '''Show Properties View'''

[[image:show-properties-view.png]]

Then, in the '''Title''' field of the '''Properties''' view, you can type the name of the book:

[[image:set-book-name.jpg]]

'''Congratulations!''' You've just created your first EMF model!