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52 votes

Is documenting a big project with UML Diagrams needed, good to have or even not possible?

Tldr Documentation should not be seen as something that you simply start doing. It carries a colossal business cost to maintain. It will require additional staff and skills in its own right. Long read ...
Steve's user avatar
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25 votes
Accepted

What are the benefits of modeling software systems vs. doing it all in code?

The benefit of modeling software systems vs. all in code is: I can fit the model on a whiteboard. I'm a big believer in the magic of communicating on one sheet of paper. If I tried to put code on the ...
candied_orange's user avatar
19 votes

Is documenting a big project with UML Diagrams needed, good to have or even not possible?

Reframing the question Indeed, managing documentation is costly. But the bigger the project, the more people involved and the longer the system's lifetime. If you count the time that it takes for ...
Christophe's user avatar
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17 votes
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Which UML diagrams are still being widely used?

From the many diagrams proposed by UML, class diagrams and sequence diagrams are still widely used, certainly followed by state diagrams: they can easily be used on white boards to elaborate and ...
Christophe's user avatar
  • 78.4k
14 votes

Representing a "wait until" in an activity diagram in UML

IMHO, there is actually no need to include any conditional or "loop" for the "wait" state at all: Any activity needs a certain time until it is completed. If a customer representative is available ...
Doc Brown's user avatar
  • 209k
13 votes

What is a proper diagram to describe software architecture

What is the purpose of the layers ? The clean architecture aims to achieve separation of concerns, by dividing the software into concentric layers. The main difference compared to the traditional ...
Christophe's user avatar
  • 78.4k
11 votes
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What comes first: the activity diagram or the sequence diagram?

There is no order for the creation of diagrams, of any type. Depending on your project, you may not even find use for some diagram types. That said, I would expect that activity diagrams, if created, ...
Thomas Owens's user avatar
  • 83.3k
11 votes
Accepted

Sequence Diagram: Are actors objects?

In UML, an Actor is always something (a system or person) that is outside the scope of the system/software that you are building. It would be completely wrong to equate an actor with an instance/...
Bart van Ingen Schenau's user avatar
11 votes
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How much UML modeling should you do?

UML covers indeed a very large set of modelling needs, from the most elementary designs, to almost visual coding, especially if considering neighbour standards such as OCL. If all these things were ...
Christophe's user avatar
  • 78.4k
10 votes

UML: what is the correct order of steps?

UML is just a language to draw pretty pictures with some chance that others understand what the shapes mean without an extensive explanation from you. UML does not tell you which diagrams to use in ...
Bart van Ingen Schenau's user avatar
10 votes

Is documenting a big project with UML Diagrams needed, good to have or even not possible?

If you have 0 documentation, jumping right into code-level documentation is going to be expensive and unnecessary. In the past, when I've inherited projects with no documentation or that unexpectedly ...
Thomas Owens's user avatar
  • 83.3k
9 votes
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UML "direct substate" vs "transitively nested substate"

Direct substate is a one level substate of a state Transitively nested substate is a substate of a substate (any levels down) Consider this diagram: For active state direct substates are filing ...
Ister's user avatar
  • 849
9 votes

How should state machines handle exceptions in actions?

State machines don't have exceptions, though they may have transitions to an error state. There's no “one size fits all” answer for how you should handle errors. This depends a lot on the problem ...
amon's user avatar
  • 135k
9 votes
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How to define a class diagram from an entity relationship diagram?

UML class diagrams can be seen - roughly - as a superset of ERDs. UML class diagram notation is younger, surely made with the intention to incorporate or replace older notations like ERD, and it ...
Doc Brown's user avatar
  • 209k
9 votes
Accepted

Where to put the the composition?

Stop using inheritance, it is the wrong tool for this job. Instead, favor compositional typing. class Car { String VIN; CarModel ModelType; Motor Motor; } class CarModel { String ...
TheCatWhisperer's user avatar
9 votes
Accepted

What does the UML symbol with a cross inside a circle mean?

After searching for something completely irrelevant (Googled "uml triangle"), I stumbled upon this: while meaning to find something like this, which is an Association Pointer: In obsolete UML 1.4.2, ...
CCG's user avatar
  • 183
8 votes

UML open diamond help

In both cases the class closest to the diamond is the one that contains the class farthest from it. The relationship indicates either a single contained object or a collection of them. Usually it is ...
Tulains Córdova's user avatar
8 votes
Accepted

How do I design a buffer for a console?

To add more flesh to the bones of Wikiti's comments. You need a fixed sized buffer and a timer set to n ms. When you write code to the buffer, if the buffer was empty, (re-)start the timer to n ms. ...
Alex's user avatar
  • 3,912
8 votes
Accepted

When "Log in" should be a use case and when not?

First, you need to specifically define what a "use case" is. At the most basic level, a use case is a set of system behaviors that products a result for one or more actors. However, some ...
Thomas Owens's user avatar
  • 83.3k
8 votes
Accepted

Navigation in Class Diagram

Navigability means according to the UML specifications: that instances participating in links at runtime (instances of an Association) can be accessed efficiently from instances at the other ...
Christophe's user avatar
  • 78.4k
8 votes
Accepted

Why is a <<create>> message asynchronous in UML sequence diagrams?

Each UML message in an interaction diagram has a unique MessageSort, which are mutually exclusive (section 17.4.2): synchCall asynchCall asynchSignal createMessage ...
Christophe's user avatar
  • 78.4k
8 votes
Accepted

Can a class contain its own class?

Can a class contain its own class? Yes. Case in point: public class Foo { public Foo Parent { get; set; } } var parent = new Foo(); var child = new Foo() { Parent = parent }; However, a class ...
Flater's user avatar
  • 52.5k
8 votes
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Do software engineers use UML diagrams of object models, domain models, system sequence diagrams and operation contracts?

Do people use them? Yes. And no. Mostly no. An UML diagram won't execute. You can't write unit tests against it. There are tools that will take production code / tables, even development stubs, and ...
J_H's user avatar
  • 7,338
7 votes
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Does UML Use Case allow "use case polymorphism"?

This answer has been updated for UML 2.5.1 specification. First, it appears that the notation is valid. Actors (18.2.1) can only have Associations to UseCases, Components, and Classes and these ...
Thomas Owens's user avatar
  • 83.3k
7 votes

Which UML diagrams are still being widely used?

On the other hand, I heard from many graduates that UML does not seem to be used in the trenches anymore. They are all used in practice. But not everyone uses them. Some people eschew design ...
Stephen C's user avatar
  • 25.2k
7 votes

Association + multiplicity vs aggregation and composition?

UML is not one of these mathematical computation models that try to achieve completeness with a minimal set of rules(like Turning machines or lambda calculus). UML is a visualization of software ...
Idan Arye's user avatar
  • 12.1k
7 votes

UML Class Diagram: How to describe method functionality?

In a class diagram, you don't typically show the functionality of a particular method. That's not the purpose of a class diagram. You're right that you can use Object Constraint Language or pseudocode ...
Thomas Owens's user avatar
  • 83.3k
7 votes
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Should we write diagram uml for our code before start programming?

Where I work, diagramming is done before, during, and after we build the product. Before Diagrams created before are used to discuss possible dependencies with other teams (which need to be ...
JRJurman's user avatar
  • 347
7 votes

Representing a "wait until" in an activity diagram in UML

Are your diagrams ok ? The guard on a decision node shall be placed on the tail of the line and not on the nodes (see UML 2.5 section 15.2.4). So [free customer representative available] on the top ...
Christophe's user avatar
  • 78.4k

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