Java代写 - Java
You will find below the specs for assignment 3. It is a rehash of A3, with some slight differences:  no simultaneous proposers  ability to use socket communication or communication through files - that is, the proposer writes the proposal to a file, and all other entities do a busy wait on reading that file  the assessment is focused on testing Deadline : please commit your code to SVN and send me a link by 5pm 22nd of December (please note that due to the University shutdown your mark, while available from me, will not be available in the system until next year). Please do not hesitate to ask me any questions. Assignment Description Objective To gain an understanding of consensus and voting protocols in the presence of failures of one or more of the participants. Welcome to the Suburbs Council Election! This year, Suburbs Council is holding elections for council president. Any member of its nine person council is eligible to become council president. Member M1 – M1 has wanted to be council president for a very long time. M1 is very chatty over social media and responds to emails/texts/calls almost instantly. It is as if M1 has an in-brain connection with their mobile phone! Member M2 – M2 has also wanted to be council president for a very long time, except their very long time is longer than everybody else's. M2 lives in a remote part of the Suburbs and thus their internet connection is really poor, almost non-existent. Responses to emails come in very late, and sometimes only to one of the emails in the email thread, so it is unclear whether M2 has read/understood them all. However, M2 sometimes likes to work at Café @ Bottom of the Hill. When that happens, their responses are instant and M2 replies to all emails. Member M3 – M3 has also wanted to be council president. M3 is not as responsive as M1, nor as late as M2, however sometimes emails completely do not get to M3. The other councilors suspect that it’s because sometimes M3 goes on retreats in the woods at the top of the Suburbs, completely disconnected from the world. Members M4-M9 have no particular ambitions about council presidency and no particular preferences or animosities, so they will try to vote fairly. Their jobs keep them fairly busy and as such their response times will vary. How does voting happen: On the day of the vote, one of the councilors will send out an email/message to all councilors with a proposal for a president. A majority (half+1) is required for somebody to be elected president. YOUR TASK: Write a program that implements a Paxos voting protocol for Suburbs Council President that is fault tolerant and resilient to various failure types, some of which are shown in the above. Communication happens via sockets or files (see above). You are responsible for the message design. Assessment Your assignment will be marked out of 100 points, as following: 10 points - testing scripts that test that your Paxos implementation works when two councillors send voting proposals sequentially (one after another) 40 points – testing scripts that test that your Paxos implementation works in the case where all M1-M9 have immediate responses to voting queries 40 points – testing scripts that test that your Paxos implementation works when M1 – M9 have responses to voting queries suggested by the profiles above, including when M2 or M3 propose and then go offline 10 points - for the quality of your code Claudia