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Dipartimento di Elettronica, Informazione e Bioingegneria Politecnico di Milano Prof. Elisabetta Di Nitto, Luca Mottola 20133 Milano (Italia) Piazza Leonardo da Vinci, 32 Tel. (39) 02-­2399.3400 Fax (39) 02-­2399.3411 Software Engineering II July 17, 2017 Last Name First Name Id number (Matricola) Note 1. The exam is not valid if you don’t fill in the above data. 2. Write your answers on these pages. Extra sheets will be ignored. You may use a pencil. 3. Incomprehensible hand-­writing is equivalent to not providing an answer. 4. The use of any electronic apparatus (computer, cell phone, camera, etc.) is strictly forbidden. 5. You cannot keep a copy of the exam w hen you leave the room . 2 Question 1 Alloy (7 points) Storm is a framework to support the development of big data applications. It offers a programming model based on the concepts of Bolts and Spouts. A Bolt is a component receiving Data Streams as input and producing Data Streams as output. A Spout is a source of Data Streams. These two types of Components (Spouts and Bolts) can be combined in various ways to form a Topology. An example of Topology is shown in the figure below. In particular, the figure highlights that Spouts can produce for one or more Data Streams and Bolts can receive data from one or more than one streams. Even if not explicitly represented in the figure, Bolts can also produce data for more than one stream. While Storm requires that a Topology is acyclic, that is, Bolts do not receive data from themselves neither directly nor indirectly, you are not required to consider this constraint. A) Define an Alloy model that formalizes the description above. Include all facts that you think are relevant to ensure the integrity of the model with respect to the informal description given above. B)…