Bug 93400 LTK UI should provide official API for structural content in the preview page
org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/ChangeElementLabelProvider.java
} else if (element instanceof CompositeChange) {
				descriptor= RefactoringPluginImages.DESC_OBJS_COMPOSITE_CHANGE;	
			} else if (element instanceof TextFileChange) {
				descriptor= RefactoringPluginImages.DESC_OBJS_FILE_CHANGE;
			} else {
				descriptor= RefactoringPluginImages.DESC_OBJS_DEFAULT_CHANGE;
			}
		}
		return manageImageDescriptor(descriptor);
	}
	
	private Image manageImageDescriptor(ImageDescriptor descriptor) {
		Image image= (Image)fDescriptorImageMap.get(descriptor);
		if (image == null) {
			image= descriptor.createImage();
			fDescriptorImageMap.put(descriptor, image);
		}
		return image;
	}
	private String getPath(IFile file) {
		StringBuffer result= new StringBuffer(file.getProject().getName());
		String projectRelativePath= file.getParent().getProjectRelativePath().toString();
		if (projectRelativePath.length() > 0) {
			result.append('/');
			result.append(projectRelativePath);
		}
		return result.toString();
	}	
}