class Not implements Clause, NeedsFutureClause {

	@Override
	public void setMissingClause(Clause clause) {
		if (this.comparison != null) {
			throw new IllegalArgumentException("NOT operation already has a comparison set");
		} else if (clause instanceof Comparison) {
			this.comparison = (Comparison) clause;
		} else if (clause instanceof Exists) {
			this.exists = (Exists) clause;
		} else {
			throw new IllegalArgumentException("NOT operation can only work with comparison SQL clauses, not " + clause);
		}
	}

	public  Not();
	public  Not(Clause clause);

}