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<div align=right>&nbsp; <font face="Times New Roman, Times, serif"><font size=-1>Copyright
&copy; 2002 International Business Machines Corp.</font></font></div>
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<td ALIGN=LEFT VALIGN=TOP COLSPAN="2" BGCOLOR="#0080C0"><b><font face="Arial,Helvetica"><font color="#FFFFFF">&nbsp;Eclipse
Corner Article</font></font></b></td>
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<h1>
<img SRC="images/Idea.jpg" height=86 width=120 align=CENTER></h1>

<center>
<h1>
Using EMF</h1></center>

<blockquote><b>Summary</b>
<br>
  This article introduces EMF, the Eclipse Modelling Framework, and will help 
  you get started using EMF in your own Eclipse plug-ins. 
  <p><b>By Catherine Griffin, IBM</b><br>
    <font size=-1>December 9, 2002 (revised May 2003 for EMF 1.1.0)</font></blockquote>

<hr width="100%">
<h1>
What is EMF, and why would I want to use it ?</h1>
EMF, the Eclipse Modelling Framework, is used to define and implement structured
data models. A data model is simply a set of related classes used to handle
the data which you want to deal with in your application.
<h2>
Some good reasons to use EMF</h2>

<ol>
<li>
<b>Code generation.</b> All the code needed for a working data model is generated for you,
based on a definition of the model.  EMF generates nice readable code, from template files
that can be customized. You can customize the generated code, and your
changes won't be lost when the classes are regenerated. The input to code
generation can be a Rational Rose model file, annotated Java interfaces,
or an XML schema definition (under development).</li>

<li>
<b>Meta-data.</b> You can programatically query the structure of a model, and
get more information than the standard Java BeanInfo or reflection would
allow. EMF also supports accessing and updating models reflectively.</li>

<li>
<b>Default serialization.</b> EMF can load and save instances of your model as
XMI (an XML format). If you need to save your data in a different format,
you can do so. XML schema as a file format is under development.</li>

<li>
<b>Links between files.</b> You can save and edit data across multiple files.</li>

<li>
<b>Editors.</b> EMF will also generate an editor for your model,
complete with content outline and property sheet. There is also a reflective editor, 
which can view and edit any EMF model file, using only the model meta-data. 
It provides similar function to the default generated editor, but it can't be easily 
customized.
</li>
</ol>
For more information see the <a href="http://www.eclipse.org/emf" target="_blank">EMF 
project page</a>. 
<p>If you want to try the example from this article, you will need EMF
and a suitable version of Eclipse (I am using 2.1). EMF version 1.1.0 
Build 20030501_0612VL was used to generate the example code.
<h1>
Developing an Eclipse plug-in using EMF</h1>

<h2>
The Example</h2>
The example used in this article is an editor for family trees. 

<h2>
Step 1: Designing the model</h2>
The first step is to design the data model for the application - that is, the 
structure of the data we want to be able to view and edit, and the relationships 
between data items. You may find a UML tool useful, or a piece of paper. For this 
application, the main information needed is who had which children. In UML, the 
data structure looks like this: 
<p align="center"><img src="images/familytree.JPG"></p>
A FamilyTree contains families and individuals. Individuals are either Male or 
Female - Individual itself is an abstract class. A Family contains children and 
is linked to a mother and father. 
<p>In addition to these types of relations, EMF will handle multi-valued
references, two-way relationships (navigable both ways), enumerations and
data types (Java objects which aren't EMF based, serialized as strings).
<h2>
Step 2: Defining the model</h2>
The next step is to define the model to EMF so that code can be generated.
If you have Rational Rose, EMF can generate the implementation of your
model directly from the Rose mdl file. See the EMF tutorial for details.
<p>It is also possible to generate the model code from annotated Java interfaces.
and that is what is described below. If you don't want to do any typing,
just create a new Java project in Eclipse, import <a href="family1.zip">family1.zip,</a>
and skip to Step 3. Otherwise proceed as follows:
<ol>
<li>
In Eclipse, create a new Java project and a package for the interfaces.
I am calling my project <b>com.ibm.example.familytree</b> and my package
<b>com.ibm.example.familytree</b>.</li>

<li>
Create new Java interfaces called FamilyTree and Family in this package.
In the Javadoc comment for each interface, add a line with the tag <b>@model</b>.
This tells EMF that this interface is part of your model.</li>

<li>
A Java interface is also needed for Individual, but this needs an extra
piece of information in the Javadoc comment because Individual needs to
be treated as an abstract class. Add the tag <b>@model abstract="true"</b>.</li>

<li>
Next create the interfaces Male and Female, each extending Individual.&nbsp;
Again add the <b>@model</b> tag.</li>
</ol>

<h3>
Defining Attributes</h3>
Individuals have names, so we need to add the attribute 'name' to the Individual
interface. Just add a method as follows:
<pre>&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return the individuals name.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @return the name
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @model
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **/
&nbsp;&nbsp;&nbsp;&nbsp; String getName();</pre>
Again, the <b>@model</b> tag tells EMF that this method needs some code
generated. If you add methods to the interface that don't have the <b>@model</b>
tag, EMF will not generate implementations of those methods, so you will
have to implement them yourself. Sometimes it makes sense to do this -
for example, you might want to add some convenience methods to the model
interfaces.
<h3>
Defining simple references</h3>
A Family should have references to a mother and a father. Add the following
methods to the Family interface:
<pre>&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return the father
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @return the father
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @model
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **/
<img SRC="images/tag_1.gif" height=13 width=24 align=CENTER>&nbsp; Male getFather();
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return the mother
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @return the mother
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @model
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **/
&nbsp;&nbsp;&nbsp;&nbsp; Female getMother();</pre>
Notice that the method&nbsp;<img SRC="images/tag_1.gif" height=13 width=24 align=CENTER>
is very similar to how an attribute is defined.
<h3>
Defining containment relations</h3>
In the UML model above, the links with black diamonds on them are containment
relations. For example, an Individual can be contained either by a Family
or by a FamilyTree. An object can only have one container. For example,
the relations between Family and Individual defined in the previous section
are not containment relations - because people can be married more than
once (even if generally not at the same time).
<p>When instances of this model are created using the editor generated
by EMF, there will be a single top-level FamilyTree object and all the
other objects in the model will be contained by it, directly or indirectly.
The model cannot be saved correctly if there are objects which have no
container.
<p>Add the following methods to FamilyTree to define its containment relations:
<pre>&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return a list of contained families
<img SRC="images/tag_2.gif" height=13 width=24 align=CENTER>&nbsp;&nbsp; * @model type="Family" containment="true"
&nbsp;&nbsp;&nbsp;&nbsp;  **/
&nbsp;&nbsp;&nbsp;&nbsp; java.util.List getFamilies();
&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  * Return a list of contained individuals
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  * @model type="Individual" containment="true"
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  **/
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; java.util.List getIndividuals();
</pre>
Unlike the simple references defined in the previous section, these methods
return Lists - thats because a FamilyTree can contain multiple Families
and Individuals. The return type must be java.util.List or org.eclipse.emf.common.util.EList
so that EMF recognizes that this is meant to be multi-valued. Notice the
<b>@model</b> tag&nbsp;<img SRC="images/tag_2.gif" height=13 width=24 align=CENTER>
declares the type of object that can appear in the List. In addition, the
flag <b>containment="true"</b> indicates that this is a containment relation.
<p>There is one other containment relation to define, in Family:
<pre>&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return children
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @return list of child Individuals
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @model type="Individual" containment="true"
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **/
&nbsp;&nbsp;&nbsp;&nbsp; java.util.List getChildren();</pre>

<h2>
Step 3: Generating the model</h2>
Now that the model has been defined, we can proceed to generate the model
implementation.
<ol>
<li>
In the File menu, select <b>New > Other...</b></li>

<li>
In the New File wizard, select <b>Ecore Model Framework</b> in the left-hand
panel and <b>GenModel model</b> in the right-hand panel, then click <b>Next</b>.</li>

<li>
On the next page, select your project source folder, enter a filename with
file type "genmodel", and click <b>Next</b>.</li>

<li>
Select the <b>Load from Java annotations</b> radio button and click <b>Finish</b>. 
Two new files will be created in your project folder, one is called <b>familytree.ecore</b> 
(this is an XMI file which contains a definition of the family tree model) and the other is the
genmodel file which you entered a name for.  The genmodel file contains additional information about
how EMF should generate code for the model.  The genmodel file is opened for editing.
</li>

<li>
In the editor, select the root (first) node of the tree and right-click
to bring up the popup menu.</li>

<li>
Select <b>Generate Model</b> to generate the model implementation code.</li>
</ol>
<p>
Two new packages will be generated in your project, <b>com.ibm.example.familytree.impl</b> and
<b>com.ibm.example.familytree.util</b>.
If you look now at the original package <b>com.ibm.example.familytree</b>, you will find that
two new interfaces called FamilytreeFactory and FamilytreePackage have appeared.  These are used to
programmatically create model elements and to query meta-data, respectively.
At the same time as generating the model implementation, EMF has also made some changes to the other interfaces
in this package.  If you look at Family.java for example, you will see that the return type java.util.List 
has been changed to EList and that the interface now extends EObject.  These changes are needed so that
the generated model code works correctly.


<h2>
Step 4: Generating an editor</h2>
The popup menu in the GenModel editor has four generation options:
<ul>
<li>
<b>Generate Model</b> - generates the model implementation code, as you
have just seen.</li>

<li>
<b>Generate EMF.Edit </b>- generates an extra plug-in containing adapter
classes needed by the generated editor.</li>

<li>
<b>Generate EMF.Editor</b> - generates an editor plug-in for your model.</li>

<li>
<b>Generate All </b>- generates the model, edit plug-in and editor.</li>
</ul>
Since we have already generated the model, to generate the editor we need
to first generate the EMF.Edit plug-in, then the EMF.Editor plug-in. This
creates two new plug-in projects called <b>com.ibm.example.familytree.edit</b>
and <b>com.ibm.example.familytree.editor</b>.
<h2>
Step 5: Trying out the generated plug-ins</h2>
The generated editor can be used as a starting point for developing your
application. However, resist the temptation to immediately start working
on fancier views. First use the generated editor to check that your data
model is able to cope with some sample data. If you find problems, you
can then redesign the data model and repeat the process until you are happy
with it. Its much easier to change your model now, than it would be after
you have put a lot of work into the editor.
<p>To run the example editor, you need to start a runtime workbench, making
sure that it will be launched with the three generated plug-ins. If you
aren't sure how to do this, see the EMF tutorial.
<p>Once the workbench has started, you need to create a model file:
<ol>
<li>
Create a new simple project</li>

<li>
Select from the menu <b>File > New > Other...</b></li>

<li>
Select <b>Example EMF Model Creation Wizards</b> and <b>Familytree Model</b>,
and click
<b>Next</b></li>

<li>
Select the new project, and enter a filename for the new file. The file
should have the extension 'familytree'. Click Next.</li>

<li>
From the combo box, select <b>FamilyTree</b>, then click <b>Finish</b>.</li>
</ol>
The new file will be opened with the editor. This is a multipage editor,
each page demonstrating different ways of displaying data from your model.
The first page is a tree view, the root of the tree being the file you
are editing. Expand the root and you will see a FamilyTree element - thats
what the wizard created in the file. Select FamilyTree and right-click
to bring up the popup menu. The menu allows you to add child elements -
Family, Female or Male.
<p>Add a Female or Male to the FamilyTree. If the Properties view is showing,
you should see the properties for the Individual - there is only one: name.
Set the name to something meaningful, and the label in the tree view will
change.
<p>When you add children to a Family, they appear as child items in the
tree. You can use the properties view to set the mother and father for
a Family, but setting these doesn't change the tree, because mothers and
fathers are linked to families, not contained by them.
<p>This is what the editor looks like when I have put in some test data:
<p align="center"><img SRC="images/testdata.JPG"></p>

<p>The test family tree shown here is in the file <a href="Test.familytree">Test.familytree</a>.
This is an XMI file.  By default, EMF uses XMI (a form of XML) to save model instance data.
If you need to save your data in a different format, you can write code to do so.
<h2>
Anatomy of the EMF Editor</h2>
As you can see, the editor generated by EMF does quite a lot. The content
outline view (bottom left in the above image) shows the contents of the
file you are editing as a tree view. Whatever element is selected in the
content outline view is also shown selected on the first page of the editor,
which is a similar tree view. Whenever you select an element either in
the editor or in the outline, its properties are shown in the properties
view. The properties view lets you edit all that elements attributes and
any single-valued references to other model elements (by picking from all
the available elements of the right type).
<p>You can drag and drop elements to move them, and cut, copy and paste, delete, 
undo and redo edit actions are supported.
<p>The other pages of the editor are -
<ul>
<li>
<b>Parent </b>- whatever element is selected in the outline view, this
tree view shows you how that element is contained.</li>

<li>
<b>List</b> - this page shows a list of elements contained by the selected
element.</li>

<li>
<b>Tree</b> - same thing again, in a tree view</li>

<li>
<b>Table</b> - a table view of the children of the selected model element.</li>

<li>
<b>TableTree</b> - same again, using a table tree control.</li>
</ul>

<h1>
Next steps</h1>
You might decide at this point that some changes to the model are needed.
For example, say I want to add a description attribute to Individual so
I can add additional biographical information. I would edit the Individual
interface as before and add the method:
<pre>&nbsp;&nbsp;&nbsp;&nbsp; /**
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * Return a description.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @return a description
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; * @model
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **/
&nbsp;&nbsp;&nbsp;&nbsp; String getDescription();</pre>
Then to update the genmodel file, right-click on it to bring up the popup
menu, and select <b>Reload...</b>. You will also need to regenerate all
the generated code. If you make changes to the generated code, then remember
to take out the <b>@generated</b> flag from the Javadoc so that your changes
are not overwritten.
<p>The generated editor is meant to be a starting point for your own development
and a demonstration of the reusable user interfaces parts provided in EMF.&nbsp;
Once you are satisfied that your model is how you want it to be, you can
start customizing the generated editor, or writing your own.
<h2>
Source code</h2>
To run the customized versions of the family tree plug-ins, unzip <a href="family2.zip">family2.zip</a>
into your <i>plugins/ </i>subdirectory. All the source code is included.
The customized editor has only two pages, the original first page and a
modified table tree view. For details of the changes see the sections below.
<h2>
Labels and Images</h2>
To change the labels that are used in the editor, you need to go and find
the adapter classes generated in the <b>com.ibm.example.familytree.edit</b>
project. In the package <b>com.ibm.example.familytree.provider</b>, there
is one adapter class for each model class. The methods <b>getText</b> and
<b>getImage</b> determine the label and image that are used in the editor.
<p>If you change the <b>getText</b> method, remember to remove the <b>@generated</b>
flag from the method javadoc comment so that your changes will be kept
if you regenerate the code.
<p>To change the icons, you can just change the gifs that are in the <i>icons</i>
folder in this plug-in project.
<p>In the customized version of the family tree .edit plug-in, the getText 
  methods have been changed in FamilyItemProvider, IndividualItemProvider, FemaleItemProvider 
  and MaleItemProvider. For example, here's the code from IndividualItemProvider: 
<pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; public String getText(Object object) {
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Individual individual = (Individual)object;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( individual.getName() == null )
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return "Unnamed individual";
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return individual.getName();
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }</pre>

<h2>
Trees</h2>
The simplest tree view is the one used for the generated editors
content outline view and the selection tree view. The content provider
for this is <b>org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider</b>,
which uses the generated adapter classes from <b>com.ibm.example.familytree.edit</b>.
The children of each element are the elements it contains.
<p>You can create different tree views by writing your own content provider.
However, make sure that you won't have the same element appearing twice
in the tree as this will cause problems. The tree viewer assumes that each
domain element maps to one tree item. If you need to show referenced elements
in a tree, you will have to wrap them. Other structured viewers (tables
and lists) behave the same way.
<p>In the customized version of the family tree editor, I have changed
the input of the content outline view so that the root of the tree is now
FamilyTree instead of the resource (file), and changed the root and title
of the selection tree view.
<p>I have added the inner class ParentAdapterFactoryContentProvider in place of 
  ReverseAdapterFactoryContentProvider. This returns the parents of a child as 
  the tree 'children', resulting in a tree showing parents, grandparents, great-grandparents 
  etc. Here's how the getChildren method is implemented: 
<pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; public Object [] getChildren(Object object) {
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Object parent = super.getParent(object);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( parent instanceof Family ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; List parents = new ArrayList();
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( ((Family)parent).getMother() != null )
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; parents.add( ((Family)parent).getMother() );
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( ((Family)parent).getFather() != null )
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; parents.add( ((Family)parent).getFather() );
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return parents.toArray();
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return new Object[0];
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }

</pre>

<h2>
Tables</h2>
Table viewers require a content provider and a table label provider.
<b>org.eclipse.emf.edit.ui.provider.AdapterFactoryLabelProvider</b>
implements the <b>org.eclipse.jface.viewers.ITableLabelProvider</b> interface,
but it delegates the real work to the generated adapter classes. Modify
these to implement the <b>org.eclipse.emf.edit.provider.ITableItemLabelProvider</b>
interface. 
Then change the constructor of FamilytreeItemProviderAdapterFactory so
that it knows it can supply a table item label provider.
<P>You will also need to set up the table with the right columns;
in the generated editor this is done in the createPages method.
<p>The second page of the editor is now a table tree, using the content
provider described above. It shows parents of children. I have defined
three columns - Parents, Father and Mother. You can expand items in the
first column to see parents of parents.
<p>I modified IndividualItemProvider so that it implements ITableItemLabelProvider. 
  The second column shows the individuals father, the third column their mother. 
  Here's how the method getColumnText is implemented in IndividualItemProvider: 
<pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; public String getColumnText(Object o, int index ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( index == 0 ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return getText(o);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; else{
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Object f = getParent(o);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( f instanceof Family ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if( index == 1 &amp;&amp; ((Family)f).getFather() != null ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // father
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return getText(((Family)f).getFather());&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; else if( index == 2 &amp;&amp; ((Family)f).getMother() != null ){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // mother
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return getText(((Family)f).getMother());&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return "unknown";
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }</pre>
<p>Heres the customized version of the editor, showing the table tree:
<p align="center"> <img SRC="images/customized.JPG"></p>
<h2>
Menus</h2>
The generated ActionBarContributor is responsible for the popup menus,
toolbar and menu bar items. The popup menu contents depend only on the
selected elements, not the active viewer.
<p>The menu items New Child and New Sibling are somewhat confusing in
this context, so I have changed the ActionBarContributor to just have the
submenu Add New, with menu items Family, Male, Female.
<h1>
Conclusions</h1>
This article has introduced the process of plug-in development using EMF
and shown how to start customizing the EMF generated editor code for your
own use. By using EMF in your own plug-ins you can benefit from reusing
user interface parts that are based on EMF. When you are familiar with
the framework, you can quickly build functional new editors and views.
<p>For more information about EMF, see the EMF tutorial (in the Eclipse Help for
EMF), documentation, and the EMF newsgroup (<a href="news://www.eclipse.org/eclipse.tools.emf">news://www.eclipse.org/eclipse.tools.emf</a>).
<p>Java and all Java-based trademarks and logos are trademarks or registered
trademarks of Sun Microsystems, Inc. in the United States, other countries,
or both.
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