elk-util-parent/elk-util-collections/src/main/java/org/semanticweb/elk/util/collections/ArraySlicedSet.java
public boolean add(int s, E e) {
		if (e == null)
			throw new NullPointerException();
		int mask = (1 << s);
		int oldMask = addMask(logs, data, masks, e, mask);
		int newMask = oldMask | mask;
		if (newMask == oldMask)
			return false;
		else if (oldMask == 0
				&& ++occupied == LinearProbing.getUpperSize(data.length))
			enlarge();
		sizes[s]++;
		return true;
	}
public boolean add(int s, E e) {
		if (e == null)
			throw new NullPointerException();
		int mask = (1 << s);
		int oldMask = addMask(logs, data, masks, e, mask);
		int newMask = oldMask | mask;
		if (newMask == oldMask)
			return false;
		else if (oldMask == 0
				&& ++occupied == LinearProbing.getUpperSize(data.length))
			enlarge();
		sizes[s]++;
		return true;
	}
Inserts a given element into the given slice

@param s
the slice id
@param e
the elements to be inserted in to the given slice
@return {@code true} if the given element did not occur in the given
slice and thus was inserted. Otherwise {@code false} is returned
and nothing is modified.