12 January 2011

Mostly-Declarative Eclipse Perspective Folders

I came across something not long ago that I did not realize could be done with perspective layouts. In the documentation for a org.eclipse.ui.perspectiveExtensions view, the relative field has this:
the unique identifier of a view which already exists in the perspective. This will be used as a reference point for placement of the view. The relationship between these two views is defined by relationship. Ignored if relationship is "fast".
Previously, I had thought that meant strictly that only a "view id" (including the ID for the editor area) could be used here - a thought that is reinforced by the tooling which lets you select any declared view ID in scope, including the org.eclipse.ui.editorss ID.

The issue in my application was that I needed a folder in the perspective - which could only be declared by the perspective factory - to be populated with view instances (same ID, various secondary IDs) from a down-stream bundle. The perspective factory can't have a dependency on the contributing bundle, and copying the view ID string literal into the up-stream bundle was not a tolerable solution.

What I wanted was to be able to declare a page layout folder as a perspective extension, or otherwise solely in the plugin.xml files for the bundles but was unable to find a way to do this.

However, as a solution, I discovered that a new folder can be created in the perspective factory code and then the down-stream perspective extensions can reference the folder's ID as a view ID. Ah-ha!

Now the solution:

public class PerspectiveFactoryWithFolder implements IPerspectiveFactory
   /** A layout folder for the right side of the perspective */
   public static final String RIGHT_FOLDER = "net.bilnoski.module.ui.perspective.folder.right";
   public void createInitialLayout(IPageLayout layout)
      layout.createPlaceholderFolder(RIGHT_FOLDER, IPageLayout.RIGHT, 0.7f, layout.getEditorArea());

Only the folders must be declared in code, and the rest I was still able to statically in plugin.xml declarations. An acceptable compromise, especially since I needed the perspective factories to exist anyway to hide the editor area.


  1. Do you get a 'referenced identifier cannot be found' warning in your plugin.xml file after doing this? It works just fine but I am looking for a way to get rid of that error... Thanks

  2. @Ethan
    I do indeed get the warning in my plugin.xml file and don't have a way to suppress it.

    Also in the example in the post is:

    which is marked as a warning also. This is another deficiency in the tooling, since the "id" field should also match secondary view IDs and wildcards. It technically is an invalid identifier, but more than simple "identifiers" are acceptable in such fields.

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