public JoinStream(IStream input, string attribute, IStream inputJoin, string attributeJoin, Opfunc selector) { this.input = input; this.attribute = attribute; this.inputJoin = inputJoin; this.attributeJoin = attributeJoin; this.selector = selector; this.index = 0; this.currentTuple = null; this.tuples = new List <Dictionary <string, string> >(); }