boolean isSatisfiable(final ElkClassExpression classExpression)
			throws ElkQueryException {
		final QueryState state = checkComputed(classExpression);
		return state.node != null;
	}
boolean isSatisfiable ( final ElkClassExpression classExpression ) throws ElkQueryException { final QueryState state = checkComputed ( classExpression ) ; return state . node != null ; }
Checks whether the supplied class expression is satisfiable, if the
result was already computed. If the class expression was not registered
by {@link #registerQuery(ElkClassExpression)} or the appropriate stage
was not completed yet, throws {@link ElkQueryException}.

@param classExpression
@return whether the supplied class expression is satisfiable.
@throws ElkQueryException
if the result is not ready