EModelService provides the ability to access model elements. The most generic usage is to seach for certain model elements via the method findElements(MUIElement searchRoot, String id, Class<T> clazz, List<String> tagsToMatch). The searchRoot is the model element from which the search will start, e.g. MApplication would be the root of the whole model. id, clazz and tagstoMatch define search criterias for model elements which can be combined.
For example to find the part with the id "mypart" use
List<MPart> findElements = service.findElements(application, "mypart", MPart.class, null);