What is the best way to trigger on object flow with a control flow in an UML activity diagram?

I want to have a control flow decide whether an object can pass through a point in a flow or not. From my understanding of control and object flows, this would not work in the way I have done it, since an object and control flow are being joined together into something undefined. What would the correct way to do this look like?

enter image description here


I’ve done some research and stumbled over this in the UML Specification:

enter image description here

Figure 15.59 is an example of using a DataStoreNode. Records for hired employees are persisted in the Personnel
Database. If an employee has no assignment, then one is made using Assign Employee. Once a year, all employees have
their performance reviewed. The JoinNode blocks the flow of tokens to Review Employee except when the
AcceptEventAction (see sub clause 16.10) is triggered “Once a year”. When the AcceptEventAction generates its yearly
control token, this satisfies the join condition on the JoinNode and, as the outgoing edge from the Personnel Database
has “{weight=*}”, object tokens for all the persisted employee records can then flow to Review Employee.

Would this not be the exact same case of an undefined join as well?

uml – Use case diagram for a web scraper

I am creating a news application as a project in which data ( the articles ) ,will be gathered and displayed on site using a web scraper.

In this project I am scraping data from different sites, storing it into database and making it view on site.
The extracted data is stored on a data base that is being connected to a back end server that feeds end points to the front end application.

My questions are:

should i have only one use case for the user since he is the only one interacting with the application ?

( there are no CRUD operations the user can only see the diffrent articles and save them or add a comment and see the diffrent comments on the article)
if not what will the diffrent uses cases be ?

Is data collection a use case?

here is a display of the architecture am using for this project

enter image description here

uml – Class diagram for permits

I have this class diagram exercise in UML. The main problem was that the permits are the works, which I did not know very well how to model it. The specification says:

Users can post their work on a website for external users. In this
Processing the job will be equipped with a web service interface.

The environment will have a web system for external users to
the company can simulate simulation work for a fee. Web users should
identify yourself to access the different works.

External users can request permission to simulate the different jobs.
in the web system, to obtain said permission they must pay the price
that the company has established for each job. The system will keep
the date simulation permission was granted for each job
to each external user. Once permission has been granted, external
users will be able to run the job as many times as necessary, the
the system will store the number of executions of each job that each external
user has performed.

The solution I proposed is the following diagram:

enter the image description here

But I have a few doubts: are access permissions and external user jobs rendered correctly?

persistence: how to properly translate UML association, aggregation and composition to Hibernate mapping?

There are a number of questions about the differences between UML association, aggregation, and composition, and many answers, some practical and some philosophical. Here I ask you if we are talking about practical differences!

In some answers I found:

  1. Reference languages ​​like Java can't really implement Compositions, since the instance life cycle is controlled by garbage collection;
  2. Associations and aggregations do not have a practical difference, so we should leave the aggregations and work with associations and compositions; Even so, those two types of relationship exist;
  3. Those three concepts only make sense in programming languages ​​like C ++, which have an instance-based (and not reference-based) object model;
  4. Aggregation allows many owners, composition does not; Some sources argue differently.

However, no answer I have found so far came close to those concepts in the context of lingering objects. No examples were given considering persistence, despite the fact that it is a very common development condition.

When an object persists in a database system, we have a garbage collection free life cycle model, since an instance deletion (or table row, if desired) occurs in response to a deliberate act of some part of the software that implements a product requirement.

The difference between Association and Composition is really very clear, they will produce different annotations in the code. A very notable difference is that with a Composition we will have cascade deletion enabled, so when the Owner identification is deleted, the Elements will also be deleted. In Association there is no cascade deletion enabled.

However, what differences will we find when noting Association and Aggregation, especially, when in both cases we have a cardinality greater than 1?

Android: How to represent an activity by starting another activity with an intention on a UML sequence diagram and class diagram?

Showing the creation of objects in UML is done like this:

enter the image description here

To communicate with asynchronously at a later stage, you would use an open arrow:

enter the image description here

As for the class diagram, I would use an association or dependency. <> not a standard keyword / stereotype. You can present it with a profile, but that is not necessary. A dependency is a weak relationship between classes. Basically you use a dependency if you just use the class in a parameter somewhere to pass it somewhere. An association is used if you have a reference to the other class and want to interact with it directly. Your code

Intent intent = new Intent(this, ActivityB.class);

is exactly that.Then it shows it as (leaving out the compartments for attributes / operations):

enter the image description here

The (public) ownership of property (indicated by the point) intent it's kind Intent. So your SD should show that fact as

enter the image description here

by suffixing the class type of the object ActivityB separated with a colon.

uml – How do I combine ControlFlow and ObjectFlow in the UML2 activity diagram?

It seems that I need to have a MergeNode with incoming ControlFlow and ObjectFlow while agreeing with paragraph OMG® Unified Modeling Language® (OMG UML®) Version 2.5.1 Merge Nodes

If the protruding edge of a MergeNode is
ControlFlow, all incoming edges must be ControlFlows, and if the outgoing edge is an ObjectFlow, all incoming edges must be ObjectFlows.

Here is the diagram:

enter the image description here

The intention was to model a process that once started continuously receives and processes order records and business records. As soon as the arrest request is received, the process stops.

Nodes A and yes they are fine since all flows are ObjectFlows. The marked nodes C and re they are problematic since InitialNodes flows are ControlFlows.

I need InitialNodes flows to initially enable the Received Trade Record and Received Order Record nodes since according to paragraph Activity Execution

When an activity is invoked the first time, none of its nodes, other than the ActivityParameterNodes entry, will initially contain tokens. However, nodes that have no incoming edges and do not require input data to run are enabled immediately.

Therefore, the received stop request will be enabled when the activity is invoked for the first time while the received trade record and received order record will not.

Is there a way to make this diagram conform to the UML specification?

If I put isControlType=true for Trade Register, Stop Request, and Order Register pins would mean that all flows are now ControlFlows according to paragraph Object Nodes:

Yes isControlType=true For an ObjectNode, ControlFlows can enter and exit the ObjectNode, object tokens can enter or exit the ObjectNode along ControlFlows, and these tokens can flow along ControlFlows reached downstream of the ObjectNode. The values ​​in such object tokens can be used to affect the control of ExecutableNodes that are the targets of such ControlFlows, although the specific meaning of such values ​​is not defined in this specification.

How general is UML really?

I just found out for the first time about Unified Modeling Language or UML (please note I'm just a hobbyist software engineer) which according to Wikipedia is a "general purpose modeling language in the field of software engineering which is intended to provide a standard way to visualize the design of a system. "

The UML website seems to claim that UML is fairly general, stating:

You can model almost any type of application, running on any type and combination of hardware, operating system, programming language and network, in UML

You can also use UML for business modeling and modeling of other non-software systems.

However, when I look at the 14 types of diagrams in UML, I'm not sure, but it seems to me that this modeling language was first of all designed to specify particular aspects of what I would call the "specification". Clearly, UML is not suitable for literally specifying all aspects of what we need from a system, and it shouldn't be: As an extreme example, a specification language like UML cannot fully capture the specification that the user interface it should be "easily understandable" ", and obviously we shouldn't expect this from UML.

However, since (of course) UML cannot be used to model / render accurate all Aspects of what we want from our system, I wonder what are and what are not the benefits of using UML: After reading some introductions, I'm still not sure what these diagrams can be used for.

  • Is UML really as useful for non-object-oriented projects as it is for object-oriented projects?

  • What aspects (in practice) of a specification can fruitfully capture UML and what is it least useful for (in practice)?

Should I include the friend function in the UML diagram?

I searched the internet but only found one answer on this. Nor have I seen anyone include the friend function in their UML diagram. Please help, I need some experienced people to answer this.

uml – Class diagram dependencies between classes

Can the requirements be expressed in class diagrams?

For example:

A student can enroll in a class.
There are different kinds
Some classes have dependencies, e.g. you cannot go to Spanish III before going to Spanish II and Spanish I.

How to model that?

List of UML use case diagrams: mandatory / optional and independent

Use cases are not intended to have any sequence between them.

The use cases are intended to represent interactions with the system that are of value to the actors (that is, the use cases correspond to the objectives of the actors). UC are in no way detailed specifications of the actions that will take place and their owner. It is just a placeholder for such specifications.

The use cases are, in principle, independent of each other, with the exception of include and the extend relationship, whose objective is to promote the reuse of common behaviors / goals / interactions.

If you want to sequence behaviors, you should consider UML activity diagrams or BPMN diagrams.