code: private ICriteria addExpressionCriterion(Restrictor criterion) {
  		ExpressionRestrictor e = (ExpressionRestrictor) criterion;
  		if (this.hasAlias()) {
  			queryString.append(this.alias).append(".");
  		}
  		queryString.append(e.getProperty());
  		queryString.append(e.getRestriction());
  		queryString.append(e.getExpression());
  		return this;
  	}
docs: Like <code>SimpleExpression</code>. But not use <code>VALUE_PLACEHOLDER</code>