elk-reasoner/src/main/java/org/semanticweb/elk/reasoner/indexing/classes/DifferentialIndex.java
@Override
	public void add(CachedIndexedObject<?> input) {
		if (!incrementalMode) {
			super.add(input);
			return;
		}
		// else incrementalMode
		LOGGER_.trace("{}: to add", input);
		if (input instanceof IndexedEntity)
			((IndexedEntity) input).accept(entityInsertionListener_);
		if (todoDeletions_.remove(input))
			return;
		// else
		super.add(input);
	}
@Override
	public void add(CachedIndexedObject<?> input) {
		if (!incrementalMode) {
			super.add(input);
			return;
		}
		// else incrementalMode
		LOGGER_.trace("{}: to add", input);
		if (input instanceof IndexedEntity)
			((IndexedEntity) input).accept(entityInsertionListener_);
		if (todoDeletions_.remove(input))
			return;
		// else
		super.add(input);
	}
/* read-write methods