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I'm starting a project with a team and we're using SCRUM as methodology. It's my first time with SCRUM. We have listed our functionalities and we made our stories, (user stories and technical stories as well as their tasks).
I've a tight UML approach to start any dev project and for me, after listing all the functionalities, the next step is to make the User Cases Diagram to let everybody see what's the application going to do and who's gonna interact with it. But my team said that there's no interest in using UML in SCRUM.
Can I use the User Diagram of UML to represent the User Stories in SCRUM? Which other diagrams can be used in SCRUM? (It could be a stupid question 'cause I cannot imagine an application without a class Diagram or a Sequence Diagram, but I really wanna see the advice from the experts in SCRUM)
Thanks.
Can I use the User Diagram of UML to represent the User Stories in SCRUM?
A use case diagram would be helpful, because it is pretty straightforward, and gives a high level idea what the project is about.
However I won't recommend to use any other UML diagram in scrum. I agree with the others that in an agile project the code changes so frequently that your diagrams will be obsolete after several days. In this case you have to redraw them, which is a waste.
For example if you are using eclipse for development, a simple refactoring step can ruin your class diagram :-(
Which other diagrams can be used in SCRUM?
I would suggest to use mindmaps. Recently we started to create our own user stories with drawing large mindmaps and put them on the office walls.
We have a feature in the middle, and we connect sub user stories to it - and sub-sub user stories to them -, and every available information we have at the moment. With this approach we have everything in one place: user stories, technical informations, questions, etc.
Of course the mindmap grows day by day, and we know more and more about the feature we have to implement.
Actually we are doing something similar described in this agile dzone article, but since you are using scrum not xp+kanban I talked about user stories not MMFs.
You can use whatever you like in Scrum that helps your team communicate effectively. Scrum makes no decisions, judgements, or guidance on what tools are effective for that team. It only asks that you reflect on the tools and practices used in executing a Sprint and make adjustments accordingly. This is the inspect and adapt loop.
Being open and honest in discussing the benefit of the tools and techniques used to deliver value requires a lot of effort and willingness by the individual members to be open to change.
What I've been told from people who've been using Scrum for a while (ie: this is opinion) is that doing UML diagrams can be a bit time consuming because as your development methodology is agile, your requirements could very easily radically change after the first sprint's show-and-tell, which means you could be doing fairly big redesigns.
Of course, do scratch up how you will tackle your tasks in the sprint backlog - you could certainly document as you go, but maintaining a central repository of class diagrams, etc. could be a slight waste in resources.
I'm not sure what's your role in the project, I'm supposing you are the PO. In that case, use additional documentation if it makes sense. Consider a user story as a reminder for the team to have a conversation with the PO about it.
If you think the user case diagram will clarify the functionality you are asking for, the it's ok. In fact, place it on the wall beside the scrumboard and burndown chart.
In my experience it is sufficient to specify for each story a "how to test" scenario. For example, suppose I have a story for Stackoverflow:
"As a user I can post a new question"
The "how to test" scenario could be:
"Click on a 'Ask Question' button, a form is displayed with a textarea for the question text and a textfield for tags. After the user enters both -they are mandatory- the user is redirected to the question list. The user can see the question title in the list, along with the tags"
So maybe a use case diagram is not really needed. I would recommend to try the "how to test" and see how it goes. It is very useful for the team because they know what you are expecting from the story, from a functional point of view. And you won't be doing documentation for every story.
If you don't like it, the go with the use case diagram, but it is a good idea to give the team something more than the story description.
Now, about the technical stories you mention. What are they? Why is a technical requirement mixed with the functional requirements? Maybe it IS a real requirement for the project, but usually it is not, and can be rewritten as a functional story. Unless your product is something like a framework or library.
For example, the technical story "create indices for the 'get questions' query" could be rewritten as "speed up the questions list page".
I only use class and sequence diagrams with Scrum because these two diagrams are live synchronized with the java code.
I certainly don't create UseCase or other diagrams or even try to generate code from diagram (e.g. MDD) because as soon as something is changed in my project and my code it is really too painful to update my diagrams. Diagrams should be automatically updated without any human intervention. I did many project with Omondo EclipseUML and it worked really well.
SCRUM is a application lifecycle management framework, not a methodology as you stated. Please refer to scrum.org
Use Cases are abstracted. If they help your team during refinement, then great. BUT once your team has committed to the story, change is welcomed and there is little point maintaining them once the story is done. The goal is always user acceptable working software!
UML state machine diagrams are useful in Scrum for projects focused on redesigning UI while retaining business logic:
State machine modeling is a dynamic modeling technique, one that focuses on identifying the behavior within your system-in this case, behavior specific to the instances of a single class. My style is to draw one or more state machine diagrams when a class exhibits different behavior depending on its state. For example, the Address class is fairly simple, representing data you will display and manipulate in your system. Seminar objects, on the other hand, are fairly complex, and therefore it makes sense to create a state machine diagram for them.
References
UML 2 State Machine Diagrams: An Agile Introduction
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I am coming from the Embedded Systems domain with more than 3 years experience.
In my current project, at the beginning, I was only responsible for only software development and the Team consisted of 3 people.
But, as time passes, hardware eng. and project lead eng. left the job respectively. So far, the project moved with a zero- architecture documentation to give an output as fast as possible. Later, new project lead took over the project and started from the begining with applying V-model. We started to create product specs->HLR->DLR on EXCEL. But now, He left the job too :). Now, I am alone on my way with nearly 700 pieces of well written product requirements. Anyway, I started to gathering and classfying requirements as non-functional, functional, business, stakeholder etc. As gathering non-functionals, I also classified them scalability, performance, regulatory, design contrains etc. So far, I did not draw any use-case. Please verify me here, what I know is that input of use-case are functional requirements. So, I created a use-case cards and now I am planning to write use-case cards for each functional requirements then also write a sequence diagram for each use-case card. Now till here, am I going right ? Does notations used in use-case such as include, extend etc. help me to create class diagram ? Is this also right way ?
Can classes be derived from use-cases?
When Ivar Jacobson invented use-cases he aimed at a development method that would be driven by the use-cases and allow to methodically derive the implementation from the use cases. That was his vision end of the 80s. His first attempt was called Objectory, which was bought by a larger company and lead to Rational Unified Process, which was generalized to be less proprietary into the Unified Software Development Process (Unified Process, or UP in short).
There is in particular one practice that allows to translate a use-case into classes: the Entity Control Boundary approach: use-cases become «control» classes, links between use-cases and actors become «boundary» classes, and «entity» classes are created for the business objects identified in (or derived from) the use-case narratives.
Once these first candidate classes are modelled, further work is undertaken during the design and classes may get reorganized to best fit into the solution (e.g. several boundary classes are regrouped for designing the GUI, and may thereafter be decomposed into UI elements, etc...).
But is this the best approach in your case?
UP is iterative and incremental, and fits well into modern version of the V-model, since the early iterations of the elaboration phase aim to stabilize the architecture and teh components (or sub-systems).
However, this may be a very time-consuming approach, especially considering the huge number of use-cases that you have. If you look at all the questions that modelling a use-case usually raises, especially if you add «include» and «extend», you risk to spend a lot of time (more than 300 days?) to draw robust use-case diagrams. And then, using ECB, your requirements might be outdated before you finish the design!
Alternatives
On the other side, some non-academic authors claim that every system has 3 to 5 really main use-cases: as a user I don't have 700 goals for using a system. So you'd better identify these and see how they relate. It's probable that many of the other requirements are far too detailed and could easily be assigned as additional information for the main use-cases.
In a similar thought, Ivar Jacobson has adapted his method to the current software engineering reality, with the use-case 2.0 approach. Don't misunderstand me, the UML would still be the same, but ECB no longer appears (modern frameworks influence much more the design of the boundaries than the use-case model, and entities are modelled using more focused approaches, such as DDD).
The idea behind use-case 2.0 is to slice the main use-cases into several smaller parts and start to develop something that makes sense for the user and can then be further refined.
I'm currently reverse engineering a ticketing system (a ticket booth system with human operator), in order to create a technical manual.
What I want to do was a flowdown from all the functionalities modeled as a workflow from the user PoV using a UML activity diagram. The objetive in this is to first lay the workflow of the user, to than specify all the interfaces/communications with databases and central systems and all the classes as class diagrams, regarding the functionalities displayed on the activity diagram.
The problem is that the system has so many options, like buy ticket, recover ticket, client info, shift managemen... the first problem i got is when i got to the main screen activity there are so many branches that i dont know if i could use a Decision point on the activity diagram.
Anyone can shed some knowledge here? Thanks to all. Cheers.
Even the system is already there the approach for building the model should be pretty much the same as if you were doing the analysis from the start. The main difference is you refer to how the system is actually used, however it's also a good occasion to discover the pain points in the current system.
Your use cases, scenarios etc will be based on what the system currently does.
Don't try documenting a complex system with just one diagram or even one type of a diagram. This approach will most likely fail. In a best case scenario you'll end up with something but it'll be difficult to impossible to read and comprehend.
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I am working on an open-source project which shows how to develop software iteratively using test-driven development and some ideas from domain-driven design. I know what I would do, however my formal skills (especially regarding UML) are a little bit rusty.
Below I am going to post my first steps with the diagrams and the explanations I would give to my readers.
I have the following questions:
The last step ends with the question But what will stich together these components?. How to show the reader the way in UML terms, while not skipping anything in the train of thought? What I plan to do is to let each component provide an Environment class. For the purpose of testing, a TestingEnvironment will gather all those environments and inject the right callbacks into the World. But which types of UML diagrams to use for showing my train of thought, and in which order? My problem is, somehow, that I know what I want to do, but I can't rationalize it to myself why I want to do it that way - I guess it has gotten a part of me to the point I don't make such decisions consciously any more.
What mistakes have I done so far, how to fix them, and most importantly: WHY?
Step 1
(0001_user_commands_use_cases.pdf)
(0002_user_commands_use_cases.pdf)
User Use Cases - Analysis
We are starting with an use case diagram (0001_user_commands_use_cases.pdf) as
part of the preliminary analysis stage. This diagram should only help us
understand what our client wants. These use cases may change over time, but
never the less, they help us understand the system we are going to develop.
Please follow the arrows while reading the following explanations.
The role the user plays when interacting first with our system will be Guest.
The Guest sends to the system some registration data, which we process.
In the diagram, we are describing what happens from a logistic point of view,
from the perspective of the client for which we write the application. We are
not referring yet to classes or objects, or the concrete workflow, which may
end up being quite different.
We are also not dealing with errors, because that would only add more
background noise to the idea - and because error handling does not add business
value to the system. Of course, a system has to be robust to errors, but keep
in mind that we're now just making the analysis - not the design of the system.
Logistically speaking, after the Guest has sent us the registration data, there
is a Registered User. A registered user can send us the login data, so that he
becomes an Authenticated User.
Following the diagram, we can see how only an Authenticated User can send to us
a request to log out of the system, thus becoming a Deauthenticated User.
Why a Deauthenticated User, and not a Guest back again? Basically, it comes
down to us not being able to foresee the future. We really have no idea how the
client will want us to extend the system - nor does he himself! Beside that,
the two roles, a Guest which we know nothing about, and a user which has just
deauthenticated, which we do know something about, are really different things.
Of course it may be that the Deauthenticated User will exist in our application
only for a very short period of time, or it may be that it's created for the
sole purpose of being destroyed back again, without being looked at by any
other subsystem of our ERP - but still I cannot stress it enough: logistically,
the role of a Deauthenticated User stands on its own.
The second diagram (0002_user_commands_use_cases.pdf) contains all the
information of the first diagram, with some added items. If you follow the
green arrows, you will see that the process is the same.
In the first diagram we notice how all three things done by the ERP system are
some kind of generalizations of a process. We have introduced this new generic
process in the second diagram as "Process Data".
Another element we have added in the second diagram is a generalization of the
three "Sending Data" elements. We are not sure how this will materialize in the
next stage (designing the system), but it looks like there's a generalization
there which may, in the end, make the system easier to maintain and extend.
We always seek new generalizations and abstractions because they have this nice
property of making the code maintainable and extendable.
Conclusion
----------
In our design, the ERP will do one central thing, "Process Data", data which
will come in in a standardized way, represented in our second diagram by the
"Send Data" use case.
We don't know how we will design these things yet, until now we have only
thought about the logistics, since we are doing just the analysis.
In the next commit, we are going to look closer at the application domain, in
order to better see the relations between all these notions and to enable us to
come up with a cohesive design.
Step 2
A rough overview of the components in the context of the application domain
Before looking at the diagram, let me first explain the thoughts I had prior to
coming up with this diagram.
We are going to design an ERP. What is this all about, and where lies the
business value in it?
We are supposedly making the product for a company which makes money by sending
products back and forth. This is the core domain of the application.
The basic idea is that a product P is moved from point A to point B, and in
this process, the company makes money.
The application will allow the company to make money by both being good at
organizing the workflow, and by making an existing workflow cheaper.
Let's say a product can be delivered to point C by taking the route A -> B ->
C, or the route A -> D -> C. The ERP must be capable of deciding which one is
better (in terms of money or time), and must manage the workflow it chooses.
So the whole point is supporting the movement of products around. Around what?
Around the world.
For this reason, let's first draw our first component: the World.
In a real project, I would continue by adding a Product component. I've chosen
not to yet, because this project is an educational one in nature, and I wanted
to get across new ideas about the architecture. If I had focused on the
products, I think there would be too much noise for the type of audience this
project is aimed at, a noise which would make the process of creating the
architecture and the architecture itself harder to understand.
We will introduce a Product component later, when the reader will feel at ease
with the architecture which, at that point, he will feel familiar with.
Instead of focusing on Products, we are going to focus on Users. This is,
incidentally, also the subject of the use cases we have drawn in the previous
commit. I think that any reader can relate to the concept of User.
So let's draw that component, the User.
Architecturally speaking, it's not that much of a difference between an User
and a Product. Instead of having Products moving around, we will have (for
now), users who live in the World and take different roles while interacting
with our system.
In the previous commit, we have concluded that there would be a standard way of
passing in data from the User to the system.
In terms of DDD (Domain-Driven Design), the data that gets into the system is
packed up as a Command. Since it looks like a good name, let's make a port of
the World component called Command Hub which will be used to receive and
process Commands from the outside.
Conceptually, the Command Hub will provide a Command Interface which any other
component can implement in order to send commands to the Hub, if it needs to.
We also want to make the components decoupled and thus reusable in different
types of applications, or to be able to combine them. This is achieved by
making an event-driven architecture.
For this reason, let's give the World component an Event Hub, which will
provide an Event interface.
But what will stich together these components?
This question is so pressing, because it's so central to our architecture, that
we will have to further investigate it.
This is not an asnwer, just a comment that would not fit into the comment box
(1) if you want to "teach your readers" something you can't do yourself, it is strange approach. Show your readers the way which works for you. Show the way "your train of thoughs runs", show the the mental images you saw in your mind, paper/pencil/photo in whatever visualization language you use
(2) you're skipping the uml-diagrams: UML 2.5 Behavior Diagrams as not useful? Even the uml-diagrams.org: UML Interaction Overview Diagrams not useful?
(3) this question looks like too broad(long) perhaps opinion-based and perhaps off-topic much more suitable for https://softwareengineering.stackexchange.com/help/on-topic
(4) for the recommended modeling workflow look at
(4.1) Cangnus's sequence diagramming comment in Stack Overflow: sequence diagram for books exchange
(4.2) BobRodes's use case scenario comment in Stack Overflow: Formal language for UML sequence diagrams
(4.3) Scott W. Ambler's Agile Modeling: Where Do I Start? for what when how and why Agile Modeling Best Practices
to name just a few
In conclusion of this my long comment, I don't see any mistakes you did. If this is description of how Test-driven Development and Domain-driven design works for you so well that you even use it subconsciously then it is just fine and ok. Being a good teach is not an easy task, good luck
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The Product owners have specific requirements around how the Product should enable the users in a complex business process workflow (approvals and what not). The easiest way to document the requirement is in the form of a process diagram/flowchart.
In Scrum however, it is advised for requirements to be in the form of user stories. What is the best way to approach this?
Option 1
Have generic user stories that encompass the workflow, and attach the flowchart diagram as a supporting document. e.g. As an author, I want to be able to submit my article for approval process so that it will get published.
Pros
it's easier for people to understand and digest - rather than reading 10-20 user stories.
Cons
it becomes an epic
Option 2 Break down the complex flowchart into its own user stories. e.g.
As an author, I want to be able to submit my article.
As an editor, I would like to get notified when an article has been submitted so that I can review it.
As an editor, I need to approve an article
As an editor, I would like to be able to request for more information
...
Pros
pure Scrum. easy to prioritize/estimate/plan
Cons
As you can see even a short business process workflow will easily explode into a lot of user stories.
I agree with pma_. Do what makes sense. In this case, you have some great looking user stories.
"As an editor, I would like to get notified when an article has been submitted so that I can review it."
If you have a ton of these, then perhaps they are too small. They would all be 1-2hrs. That's probably not a good thing to have. In that case, try grouping them. Perhaps
"As an editor, I want to be able to manage articles". That would include several of the ones you have already.
Keep in mind the goals of user stories...
Track items on a burndown chart
Deliver fully functional work (not an unusable subset of work)
Have estimatable portions
If you can achieve those goals, you're good. If not, try again.
Oh, and one last thing - keep the flow diagram, don't throw it out in favor of stories. But supplement the stories with it.
If this business workflow is like most business workflows, each of those steps will have a significant number of rules. Those rules should map into acceptance criteria for those stories and ideally, automated tests to prove that the code works as intended. Because of the potential for a lot of acceptance criteria, I would lean towards the second option.
I tend to go towards Features/Epics early on with the core end user/stakeholder value-adding functionality, such as in your example to "Publish an article so that the subscribers can get the latest news". Then once the Feature is getting closer to implementation I'll split it into implementation sized stories if needed.
Most non-trivial business workflows benefit from being split up during implementation so that they can be continiously deployed and verified in order to get early feedback from the stakeholders. The big con of having everything as one big bang implementation is late validation. I think that having early feedback is outweighing the increased administrative burden of handling multiple stories.
A tip on how to split epics into stories: Lasse Koskela has a great writeup on how to split stories in different ways.
For me all agile is about using common sense. I this case you have perfect desing so just implement one and don't look for unecessary things.
We're currently building a business process based content management system. We split our processes into stories as per your 2nd option.
But, of course, we keep the flow diagram handy. In fact, we print it out and stick it to the wall. We even keep every old version of it so we've our own paper based version control stuck to our wall (in addition to using git for the electronic version ;-) )
In Scrum however, it is advised for requirements to be in the form of user stories. What is the best way to approach this?
The two options that you have mentioned are not really options, they are sequential stages, IMHO. During Agile Requirements Gathering or Product Planning the first step is to create EPIC stories. After you have those Epics, you need to break them down into smaller chunks.
Without the EPICs you will most likely to run into the issue of creating random stories without getting a grasp on the sense of belonging of a story. You can in a way create a hierarchy in User Stories. Without understanding that, everything is just random, hence it makes it tougher to wrap your head around or manage the stories as a PO.
Offcourse there is much more to all this than what I mentioned in the above paragraph. That's why probably you need an experienced Scrum Coach or do a lot of diligent reading/implementing on Agile Planning and User Story writing.
Hope this makes sense. I would suggest reading Agile Estimating and Planning by Mike Cohn for anyone who even remotely thinks of taking up a PO role. Best of Luck!
Workflows are an interesting entry to writing user stories and epics, but user stories don't map to work flows, they map to business capabilities. So you are incorporating some fallacious thinking from the start in this question. Workflows are a good tool for the conversation, but will live independently of workflow as they are about functionality, not timing. Timing lives in the business rules.
On that note, business rules are not Acceptance Criteria, they are the connection between Acceptance Criteria, which are features that can be demonstrated by a product owner, and Test Cases. Again, Acceptance Criteria are about features, not behavior. Behavior lives in the business rules.
For instance I might have User Story for an ATM that says "As a user, I can check my account balance." And the Acceptance Criteria could be "If I am overdrafted, I get an alert notice." The rules for what constitutes an over draft (I had $1000 in my account and deposited my $2500 pay check, but that won't clear before my $1500 mortgage payment, etc.) are not acceptance criteria. They are business rules whose execution results in the demonstrable action of the Acceptance Criteria. Note, that this user story could be captured through a workflow analysis, but might live in many workflows (or none).
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If I divide development of a particular feature into multiple stories:
First one for a high level design of the feature,
Based on first story I create other stories to develop the different stand-alone pieces that compose the feature,
Does it mean I'm doing waterfall?
Furthermore - if I divide development of the previously identified stand-alone pieces into design and implementation.
Would that mean that I'm doing waterfall?
Note: I am big time Scrum novice.
There is no such thing as design and implementation stories, User Stories should provide some level of end-to-end functionality to the user (i.e. delivering customer value).
The fact that you are mixing the terms stories and features doesn't help to communicate but what you're describing sounds actually like tasks (Sprint Backlog level), not user stories (Product Backlog level).
And if they are not tasks, then they are very bad stories. Maybe the "functionality" is too big and you should put the story on diet but what I see here is a typical story smell.
If you are new to User Stories, I strongly recommend to use the regular template (As a <type of user>, I want <some goal> so that <some reason>) and also to follow the INVEST model. This will really help you to avoid pitfalls like the one of your question.
Back to the real question (Am I doing waterfall?): there is nothing wrong with doing so design inside a Sprint (as a task of a story). But if your whole story is about design, you're not really doing Scrum, you are supposed to deliver a demonstrable end-to-end increment at the end of the Sprint.
Scrum stories tend to be about "business value":
Business value is a concept that describes the relative worth of any development effort to the business. Business value is often unquantifiable, but often relates to money.
You can think of business value as something that could still be sold if the project was stopped.
If you write a story to create: "a high level design of the feature", what you would produce by implementing that story isn't something that the business can sell. It's not something customers can try, buy, use. In effect, the business value of that story is zero.
You might have better luck thinking about stories "vertically". "Vertical slices" are minimal features that cover your entire technology stack. For example: "A user should be able to enter their name in a text box, click a button, and be shown their record in the database." It's not, by itself, especially useful, but it is more valuable than a feature design.
No, you're not. The sub tasks can be added to the backlog (presumably with roughly equal priority so they come out around the same time) and then the super-task would be to integrate/test/etc the separate components.
It sounds like a valid way to breakdown a large component to me. Just make sure you size up the different chunks appropriately. I've found 4-16 hour chunks work best. Giving 40 hours for a task means they'll do 2 hours of work until Friday when they cram the other 32 in (along with lots of bugs).