code: public IProject ifSpecificConfiguration(String preferenceContainerID, IProject project) {
  		if (project != null && hasProjectSpecificOptions(preferenceContainerID, project)) {
  			return project;
  		}
  		return null;
  	}
docs: Filter the project according to the specific configuration.
  
  <p>If the given project has a specific configuration, it is replied.
  Otherwise, {@code null} is replied.
  
  @param preferenceContainerID the identifier of the generator's preference container.
  @param project the context. If {@code null}, the global context is assumed.
  @return the unmodifiable preference store.