So, you want your plug-ins (present and future) to add view(s) to some perspective you have defined. You can do this by the means of the org.eclipse.ui.perspectiveExtensions extension point and targeting you chosen perspective's id and providing the view elements at will.

In my context, I just wanted to define a generic initial layout (that is, subdivided the perspective's whole area in zones) and let the plug-ins fill the specific areas. Something like this:


Which is archieved by a PerspectiveFactory which defines three area (left, top and bottom). In code terms:

public class DefaultPerspective implements IPerspectiveFactory {
    /** The standard perspecive used in the application. */
    public static final String PERSPECTIVE_ID = UiPlugin.ID
            + ".perspectives.defaultPerspective";
 
    /** Left folder's id. */
    public static final String FI_LEFT = PERSPECTIVE_ID + ".leftFolder";
    /** Top folder's id. */
    public static final String FI_TOP = PERSPECTIVE_ID + ".topFolder";
    /** Top folder's id. */
    public static final String FI_BOTTOM = PERSPECTIVE_ID + ".bottomFolder";
 
    private IPageLayout layout;
    
    /**
     * We replace the editor area with three application folders that can be used for placing views.
     * 
     * @param the layout
     */
    public void createInitialLayout( IPageLayout layout ) {
        this.layout = layout; 
        String editorAreaId = layout.getEditorArea();
        layout.setEditorAreaVisible( false );
        layout.setFixed( false );
        
        layout.createFolder( FI_LEFT, IPageLayout.LEFT, 0.25f, editorAreaId );
 
        layout.createFolder( FI_TOP,IPageLayout.TOP, 0.60f, editorAreaId );
        
        layout.createFolder( FI_BOTTOM, IPageLayout.BOTTOM, 0.10f, editorAreaId );
    }
 
    /**
     * @return Returns the layout.
     */
    public IPageLayout getLayout() {
        return layout;
    }
}

We define the three areas by creating three known IFolderLayout objects: later this ids will be useful when placing our views.

Every plug-in defines a view element which attach the view to a specific perspective and provides additional info. In example:

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.0"?>
<plugin>
   <extension
         point="org.eclipse.ui.views">
      <category
            name="eConference Views"
            id="it.uniba.di.cdg.econference.ui">
      </category>
 
      <view
            id="it.uniba.di.cdg.econference.ui.handraising.handRaisingView"
            name="Hand raising"
            icon="icons/view_icon.png"
            category="it.uniba.di.cdg.econference.core.ui"
            class="it.uniba.di.cdg.econference.ui.handraising.HandRaisingView"
            />
   </extension>
   
   <extension
         point="org.eclipse.ui.perspectiveExtensions">
      <perspectiveExtension targetID="it.uniba.di.cdg.econference.core.ui.perspectives.defaultPerspective">
         <view
               id="it.uniba.di.cdg.econference.ui.handraising.handRaisingView"
               ratio="0.60"
               relationship="stack"
               relative="it.uniba.di.cdg.econference.core.ui.perspectives.defaultPerspective.bottomFolder"/>
      </perspectiveExtension>
   </extension>
</plugin>

Note the relative attribute: this is the key for the correct placing. It requires another view's id which is present in the perspective (maybe defined in the same way) but it works with named IFolderLayout objects too. In this example we place the new view in the bottom folder and when the application shows up, this is the result we get:



In this case I used the relationship="stack" placement but you could put your view on top / bottom and to the left / right, of your relative object.

You can do the same for an arbitrary number of plug-ins or for plug-ins which define more than one view.

Hope this will help some other people when trying to avoid strict coupling among the perspective layout and the views that may compose it.

  
IPlaceholderFolderLayout leftFolder = layout.createPlaceholderFolder(FI_LEFT, IPageLayout.LEFT,0.35f, editorAreaId);