When a new page is created in the workbench a perspective is used to define the initial page layout. If this is a predefined perspective (based on an extension to the workbench's perspective extension point) an IPerspectiveFactory is used to define the initial page layout.

The factory for the perspective is created and passed an IPageLayout where views can be added. The default layout consists of the editor area with no additional views. Additional views are added to the layout using the editor area as the initial point of reference. The factory is used only briefly while a new page is created; then discarded.

To define a perspective clients should implement this interface and include the name of their class in an extension to the workbench's perspective extension point (named "org.eclipse.ui.perspectives"). For example, the plug-in's XML markup might contain:

 <extension point="org.eclipse.ui.perspectives">
   <perspective
       id="com.example.javaplugin.perspective"
       name="Java"
       class="com.example.javaplugin.JavaPerspective">
   </perspective>
 </extension>
 

Example of populating a page with standard workbench views:

 public void createInitialLayout(IPageLayout layout) {
		// Get the editor area.
		String editorArea = layout.getEditorArea();

		// Top left: Resource Navigator view and Bookmarks view placeholder
		IFolderLayout topLeft = layout.createFolder("topLeft", IPageLayout.LEFT, 0.25f,
			editorArea);
		topLeft.addView(IPageLayout.ID_RES_NAV);
		topLeft.addPlaceholder(IPageLayout.ID_BOOKMARKS);

		// Bottom left: Outline view and Property Sheet view
		IFolderLayout bottomLeft = layout.createFolder("bottomLeft", IPageLayout.BOTTOM, 0.50f,
			"topLeft");
		bottomLeft.addView(IPageLayout.ID_OUTLINE);
		bottomLeft.addView(IPageLayout.ID_PROP_SHEET);

		// Bottom right: Task List view
		layout.addView(IPageLayout.ID_TASK_LIST, IPageLayout.BOTTOM, 0.66f, editorArea);
	}
 

Within the workbench a user may override the visible views, layout and action sets of a predefined perspective to create a custom perspective. In such cases the layout is persisted by the workbench and the factory is not used.