Deal qualification for Engineering

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hi software engineers now coming to you from the flower and garden festival here at epcot at beautiful walt disney world more places i'd love to be of course hope you're doing well we are now moving past software process software methodologies moving into the first phase of development so this second unit in the course is all about requirements and requirements engineering and that is exactly what we're going to get to today so requirements engineering is actually a sub field of software engineering well the basic idea is how are you going to go about understanding what it is you actually need to build now if you remember my story uh that i told during one of the online meetings but it's also posted at cs3240.cs.virginia.edu i worked on a piece of software for appalachian service project wonderful people back in the summer of 1999 and long story short over two decades later i'm still performing maintenance on this piece of software now your software will haunt you is a little hyperbolic obviously but the point being is that the cost of software is not in the actual building of it the cost of software comes in the maintenance of it in the keeping it working and the keeping it running so this is my first rule of software whenever you're building a piece of software make sure you're thinking about well how is this going to live into the future how are we going to make updates who's going to own it how is it going to be all of that stuff be thinking about that because that's really really really important so let's try to figure out the second rule of software and for that i want you to take a moment and think about this let's think about a student organization a ce a cio at uva comes to you and says hey can you build us a website that allows students to sign up for events let's pretend they're virtual events right now uh that they're putting on seems reasonable right so what i want you to do is hit that pause button hit that pause button take one moment and i want you to think about this okay what would you do what would you ask them are you thinking are you still thinking let's go okay now um you might ask them how many people will use it you might ask them does it need to be behind that badge you might ask them do they need to pay anything to register you could probably come up with several questions probably the most important question is can you just use a google calendar can you just use a doodle file doodle app this is a solved problem do you really need to rebuild new software do you really as a software engineer need to go off and make something brand new when it kind of already exists which comes to sheriff's rule of software number two make sure you're solving the right problem it could be that you as a software engineer get you know given a problem and you get super excited about oh man i can't wait to build this and react and uh have uh jason uh rest api and it's gonna have a mobile front and you just get so excited about all the cool stuff you're gonna do when all you really need to do is help them set up a google account yeah we get super excited we get super excited about helping people about doing this cool stuff but we need to focus on the customer we need to focus on the stakeholders our role as software engineers is helping other people do their jobs better live better lives do whatever it is they need solve their problems help them solve their problems now we don't necessarily know all the domain knowledge that we need to solve every problem this is one of the reasons why we like it uh for you to take a lot of hss courses so you can you know hey i had a class in economics hey i kind of understand sort of what's going on when you go work at like or something like that maybe you need to understand what their problem is you need to talk to them you need to get a feel for what actually are we trying to do are we trying to make you know build the latest greatest newest and most amazing thing or or can we just use something that's already in existence so we're trying to get these software requirements out of the out of the stakeholder um so a software requirement a condition or capability needed by user to solve a problem or achieve an objective this is what the software has to do in order for it to be successful right um it has to allow me to record people's address it has to allow me to upload to a serve whatever it might be okay must be met or possessed by a system or component to satisfy a contract standard specification or formal constraint it could be that because uh it is a particular type of security software maybe has to meet some sort of standard uh maybe because it's medical software it has to have certain sort of uh redundancies these are all requirements on the software i love this quote from the pragmatic programmer requirements are often buried deep beneath layers of assumptions misconceptions in politics we as software engineers tend to think we might know more about someone's problem than we actually do and that leads us to make guesses about what the customer actually wants or needs and this leads us to build the wrong software or build something poorly or build something that doesn't meet the actual need we need to learn how to listen we need to learn how to actually have a conversation and figure out what the needs are never assume you know what the customer wants never you need to be an advocate for what you think they need but have that conversation and understand what their needs are so requirements engineering the systematic way of developing requirements through an iterative process and analyzing a problem documenting the resulting observations and checking the aggregate yeah basically the same ideas that we apply to software engineering versus coding right coding is i'm going to go in and slam out some code in vs code and make some you know make something appear on the screen two thumbs up that's awesome software engineering the systematic way of building software so that it's meant to last so that you make sure you take into account everything you need to understand requirements engineering the the the programming version of that is walking into a room and saying hey man hey ladies hey everybody what is it you need and i'm just going to write it down on a piece of paper cool and i'm going to go start slamming out code requirements engineering is a systematic process for how do we sit down with the customer how do we tease out what the need is how do we understand what we are going to build so requirements engineering is an entire subfield that does really cool stuff um what we're going to talk about mainly is just kind of the basics of what every software engineer needs to know and that is requirements analysis and requirements modeling so requirements engineering is basically broken into two phases great more phases thanks share yeah i know okay requirements analysis also called requirements elicitation is the act of studying the needs to get the definition of a system part of it is interacting with the customer part of it is um looking at what is in the market that's one part we'll talk about that in a second the second part requirements modeling or requirement specification that is the translation of what you just did in requirements analysis and elicitation on gathering the information and converting it into something that a developer can act on you know if someone says hey i need you to you know build this secure that's a bad example but sure build this secure what does that actually mean what are we actually programming so requirements elicitation the process of gathering requirements from the stakeholder now the definition of stakeholder is any entity or representative of a group that has a vested interest of the system i want you to pause one more time and i want you to think well i don't pause okay don't pause just yet let me ask you the question who are the stakeholders or cis who are the stakeholders or cis who are the people that have a vested interest in the system okay you still thinking how's that thinking going okay um students because you use cis obviously for signing up for courses administration or administrative things finance the registrar's office um faculty advisors faculty advisors who have to go in and like when i log into sys i see a completely different system you do um when i go into sys i have the ability to go in and remove holds in that sort of jazz i don't have a finance tab my finance stuff is in workday because that's where i get paid so i don't see any of that in sys but there's other stakeholders such as the board of visitors you know the the university system these are all entities that have a vested interest in what this software can do so we need to build software or in this case purchase software customized software that has to satisfy all of these needs how do we do that who who matters more who matters less who do we listen to more i know what you're going to say they don't care about the student i mean they did have to look at the student interface at some point but i could make the same argument for faculty so they had to consider things though that you might not think about like how how robust is the software against failure we can't lose people's we can't lose people's um student records we can't so we need to make sure that we are picking picking the right solution that handles those problems so once we know who we're going to talk to who these stakeholders are what are we trying to get out of these out of these individuals another classification functional non-functional and constraints functional requirements non-functional requirements and constraints let me just go ahead and jump to them one at a time a functional requirement is exactly what you think it is the system shall something the system shall allow user to log in with the username and password the system shall allow user to post a message that on the message board that anyone can read the system shall allow a faculty member to remove a hold from a student the system shall et cetera et cetera et cetera as much as possible a functional requirement needs to be specific and unambiguous measurable and observable and testable in some way so let's let's think about this for like a music player okay if i just say the system shall play music play music how play music when i shake it play music when i press a certain button play music when i sing to it play that's not specific enough the system shall play the current loaded song or the first song let's say that the system shall play the first song of the current playlist when you press the play button that's more specific that's something that's observable if i press the button and it happens okay i tested it and made sure it happened but if i just said the system should play music play music when i press the button it starts playing music 10 days from now these are obviously silly sounding but this matters how about a to-do list the system shall allow user to make to to record a to-do again how why how does this operate do i have to get down to the nitty gritty of it to say it will record it to do as an xml document that then is stored no that's actually called implementation bias when you put that sort of information into the requirement itself you are trying to tell the programmers how to do their job as a requirements person and that's not what you want what you're trying to capture here is the functionality the system shall allow you to mark off a to-do item by tapping the name of the item that's a good one text editor the system shall underline misspelled words ing to the dictionary loaded i don't want to give a specific dictionary that's implementation bias but a loaded dictionary something like that okay these are all things that if i read it if you read it if the desi if the programmer read it we would all have a similar understanding of what the requirement is this is really really important because so much about software engineering boils down to clear communication can we understand what the customer needs can we then translate that to something that the developers can build can we translate that into something that the qa folks can test that we then can show to the customer or other stakeholders at the end how do we understand what we are building and we're going to talk about communication throughout the entire semester and how important it is not only for the building of understanding the software but communication like in your teams with management all of that but here it's communication in in the respect that am i as a requirements engineer listening to my customer enough that i can write down plain language requirements that i can then show them and say this is what i think you mean am i right and if they say yeah that's awesome i got it now your job is to clearly communicate that to the developers it's like the weirdest game of telephone you've ever played that's why we have these processes to try and make sure that we can pull this off so these are functional requirements these are the things that the system does right it is a functionality contrast that with non-functional requirements non-functional requirements are harder to kind of wrap your head around because they deal with aspects of the system that aren't localized to a feature per se to a button i guess right so i want the system to be secure great everyone wants that but there's not like let me import security module and it just does it security is something you have to think about throughout the entire process it pervades all of your features right privacy same thing how are you protecting people's data usability accessibility what color schemes are you using are you making it able for screen readers to work with are you making it so that colorblind people can understand what they're seeing for instance example there you might have you know it needs to be accessible for colorblind people one thing that you might do is for a certain colorblind like whichever colorblind type someone is to use an icon with a color so that when someone who is colorblind looks at a button looks at some sort of action there's both a picture and a color that can be used to identify the functionality this is actually very commonly used in board games believe it or not go look at ticket to ride the colors on each of the train cars also has a symbol i'm diving into a different topic but that's that's not something you just do one place there's not the universal make work for colorblind button that you do reliability did you build your entire system to handle 10 000 simultaneous requests how are you handling that devops process so that your servers can handle more traffic availability is the same thing performance same idea you know how robust is your system it's not that you just did it right in one spot a non-functional requirement talks about the state of the system it talks about how did you build the entire system with this concept in mind so these are probably you know a relatively exhaustive list but you can probably think of some more um they are not limited to one function not one limit to one class you know these are things that come up when you're talking to a when you're talking to a customer to a stakeholder and they say it just needs to be secure it just needs to be fast well what's fast you want every requirement to be specific unambiguous so fast might be a page loads in 100 milliseconds now you have something you can test okay so even with nfrs you you as much as possible you need to have something that can do a test for things like usability and accessibility there are tools out there web tools that will go through a web page and see whether it would pass a screen reader whether a screen reader can handle it or not something you should think about okay um if you do something wrong in an fr if you're not thinking about that nfr from the beginning you might have to redo your entire system so if for instance you pick a certain framework or a certain platform or certain algorithm and it has to handle a certain number of transactions per minute or per second or whatever metric you're using if you get it wrong and then you build out the system you might have to rebuild the system so the point there at the bottom working with the customer to figure out your nfr requirements that was like atm machine your non-functional requirements as early as possible is really important how secure does this piece of software need to be how reliable how available how fast what what are the conditions under which this piece of software is going to run so think about in terms of cis you know we can talk about what does a student need to do when they log into sys they need to register for courses pay for their bills yada yada but then we also have to think about what happens to sis during the weeks of registration how many concurrent users can it handle no jokes um how many how much uptime does cis need to have you get the idea how secure does cysts need to be those all thing you have to think about how is the software going to be used because if you don't then you get in a problem like like for instance the um the healthcare example as well they didn't think as much about those concurrent users for when it was really getting hammered the last type of requirement is a constraint so a constraint is something that is not it's not an nfr but it limits your options for how you build the software so the best way to think about it is because of the infrastructure at a company they say this has to be written in c sharp c plus plus java python whatever because once you as a software engineer are done with it and you've turned it over to them that's what their development team knows and that's what's going to allow them to perform maintenance on their own so a constraint is you need to build it in a particular language a constraint limits your solution space saying you must use this library you must use this operating system you must use this programming language whatever it might be okay so um nfrs are not constraints constraints are not nfrs constraints limit your options for what you can build so i know you haven't gotten your project design you private depends on when you watch this i guess you don't know exactly which project you're doing yet but just think in general for the projects that we're talking about what are some examples of functional requirements non-functional requirements and constraint let's do the easy one first you have to use django you have to use python you have to use heroku you have to use github those are constraints that we have put on you for your solution space you can't go off and build this in ruby on rails that's an unacceptable solution now do we say you have to use bootstrap no i think that's a good option just for you know learning web development's sake learning bootstrap's not a bad thing but some of you might say no i'd rather do this in react or whatever great that's not a that's not a constraint we've put on you but that's an example of a constraint what's a non-functional requirement well how secure does this need to be because it's a it's a class project we want you to think about these things but we're not going to super enforce you must handle 10 000 concurrent users or anything like that we're not going to super enforce things like it has to um be such and such security i mean there's some level of security we will expect so i guess that i guess there is a notion of it which it must be protected by a google login non-functional requirement when you go to a page you gotta handle that the functional requirements are what the system is going to do right anything like a user has to press a button to do a thing that's going to be a functional requirement so that's the basics of what requirements engineering is it's the idea that we're working with the stakeholders to help them understand what their needs are making sure we are listening as much as possible communication is so important here and teasing out those functional requirements the the system shall this is what the system will do um the actual measurable repeatable um unambiguous things if i press a button this is what happens the non-functional requirements the state of the system how reliable how accessible the usability and then the constraints how do i limit my design space i have to use this programming language i have to use this this library so that's a good place to stop with this video next time we'll talk more about the specifics of how you actually go about eliciting those requirements so until then from epcot hope you're having a good day