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Create class diagrams in seconds with GenMyModel, a free uml online tool to draw UML diagrams.

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GenMyModel is an UML editor with powerful features for creating UML class diagrams, in the web browser. GenMyModel
helps you create class diagrams right away, there’s no install, no setup and no learning curve to get started.
Classes, operations, attributes, relationships are created within a click from a user-friendly toolbar and shortcuts.
You can draw class diagrams online in seconds and the intuitive GUI makes it very easy.

Supports content-assist

At anytime, GenMyModel assists you draw a valid UML class diagram by highlighting the UML elements that match an UML-compliant architecture. It saves time when creating UML elements such as attribute’s type, inheritance, realization (interface) or dependency.

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UML Class Diagram


The class diagram in the Unified Modeling Language (UML) is a type of static structure diagram that describes the structure of a system.
It contains the system’s classes, their attributes, operations and the relationships among the classes. The class diagram is the main building block of object oriented modeling. It’s the most common starting point for software architects and developers when designing a system.


Within GenMyModel, you can create your class diagram online and generate Java code. Everything is handled in your web-browser with an intuitive user interface. The class diagrams conform the UML standard. You get both a visual representation, called the diagram, and the internal structure of your model in a tree-based representation. It works on Windows, Mac, Linux and the supported browsers are IE, Chrome, Firefox, Safari and Opera.

Class diagram examples

GenMyModel comes with many free examples, clonable within a click. Shown above are some UML diagram templates available to our users. You can access this professionally designed templates from the dashboard area. The examples contain class diagrams but also use case diagrams and activity diagrams.

  • Class diagram online shopping cart

    Online Shopping Cart class diagram

  • Pattern Adapter Class diagram

    Pattern Adapter class diagram

  • Bridge Class diagram

    Pattern Bridge class diagram

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Learn more about how to draw more diagrams in GenMyModel:  Flowchart software ,  Activity diagram online


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UML Class diagrams with Rhapsody

University of Colorado System
From the course by University of Colorado System
Software Design Methods and Tools

13 ratings

University of Colorado System
University of Colorado System

Software Design Methods and Tools

13 ratings

Course 3 of 4 in the Specialization Secure Software Design

Since many software developers are compulsive coders, they have created software over the years to help them do their job. There are tools which make design and its associated tasks easier. The course introduces some basic tools and techniques to help you with design. Tools aren’t always tangible, however. The last two lessons of this course discuss questions of Ethics in software development. The purpose here is, as with tools, to equip you to better carry our your responsibilities as a designer. Students will be required to have a prior knowledge of writing and delivering software and some programming knowledge in java.

From the lesson
UML Tools
An introduction to IBM Rhapsody, a UML modeling tool.
UML Class diagrams with Rhapsody9:12

Meet the Instructors

  • Albert Glock
    Albert Glock
    Computer Science

Hi. In the last lesson,


you may have downloaded and installed


IBM's Rational Rhapsody which used to be Rational Software's Rational Rose.


The software package is a useful design tool.


From its beginnings, this tool contained


a data driven description of the design and allowed various views of the design,


class diagrams, sequence diagrams,


and so on, to be linked to one another.


If you haven't installed Rhapsody,


you can still learn from this lesson.


We'll talk about what goes into a class diagram,


so you'll see what it looks like.


You'll be able to construct class diagram for example with PowerPoint.


Okay, now that Rhapsody is installed, let's use it.


To make this a little more convenient,


if your install did not create a desktop icon shown here,


mine didn't, you can create one yourself.


Go to the install folder,


the path to my install folder is shown here.


Then click on Rhapsody.exe,


right click on it and select Create Shortcut.


Windows will tell you that it can't put a shortcut in


the folder and wants to put it on the desktop.


That's what you want to do anyway, so click Yes.


It had a long name,


so I shortened it just to Rhapsody as shown.


You'll see the script R icon on


your desktop and you need only double click on it to run Rhapsody.


Let's do that now.


To create a new project,


click on the new project tile.


You'll get a dialog which asks for a project name.


If you simply type the project name and click OK,


you'll get this error because Rhapsody defaults to the path where it's installed,


but you're not allowed to write there.


Instead, type a name of a project and a different location in the path as shown.


The name I chose was SMS for student management system.


This will elaborate a little on the student and


course relationships we talked about before.


We're not going to design the whole system,


just enough so that you get


some familiarity with the mechanics of creating a class diagram.


Then click OK and you'll be off and running.


Next, you'll get this configuration dialog.


Just click Yes and proceed.


This will present the drawing surface you have to work with for the class diagram.


Let's create our first class diagram.


What we want to do is drag the class tool from the panel on


the right side over to the left side of the drawing surface.


It will create a class object with the name already selected so that you can rename it.


Rename it to Student.


It should look like this.


Next, we want to add attributes to our class.


To do this, right click in the Student class and from the context menu, select Add New.


This will produce another context menu from which you would select Attribute.


Doing this will place a generic attribute in the student box which


you can rename to Id:int.


This done, continue to add the following attributes.


Go ahead and pause this talk if you wish so that you can finish adding these attributes.


Now that you've got the Student class built,


let's build the Address class.


Go through the procedures you did above and add the following attributes.


Go ahead and pause the talk if you want to finish


adding the Address class before we continue.


Next, we want to


create an association between the Student class and the Address class.


To do this, click on the Association tool in the right panel and then,


click and drag the Association from the Student class to the Address class.


The result should look like this.


If you double click on the Association,


you'll get a dialog which will allow you to modify features of this Association.


On the General tab,


you can modify the End names of the Association.


In this case, I changed the End1 name to Address and the End2 name to Student Address.


Then click OK.


What we've done here, is created the Association for the Student Address Attribute.


This is a reference to a single address which should be the Student's current Address.


There is another Association with the Address class however.


This has to do with the Historical Address Attribute


which can be a list of previous Addresses the Student has had.


To do this, create another Association between Student and Address,


label the Ends, StudentHistAddr and Addresses.


Rhapsody won't let you name the Ends the same as the End in another Association.


You should end up with something that looks like this.


Another adjustment we'd like to make,


is to show the Association as an Aggregation.


To do this, click on the Associations to select it,


right click on it,


in the context menu,


select Change to and then, Aggregation.


This should result in a diagram that looks like this.


Note the hollow diamond on the Student End of the Association.


This is what an aggregation looks like in a UML diagram.


This says that, a number of Address objects maybe,


but don't have to be,


associated with the Student object.


The alternative to an Aggregation is a Composition.


This is represented by a solid diamond in a UML diagram.


Its implication is that,


you cannot have a Student object unless you have a set of Address objects.


That's not the case in our situation,


so the Association is an Aggregation.


However, the Association between Student and Address for


the Historical Addresses Attribute is a one too many relationship.


To show this in the diagram,


double click on the Association,


go to the End1 tab,


in the multiplicity dropdown,


select the single asterisk then click OK on the dialog.


The final diagram at this point should look like this.


There are three more classes you can add to the diagram.


You may want to pause the talk while you do this.


And this is what the results should look like.


As an aside, you may have noticed


some strange screen artifacts when you try to


reposition the dialog on the drawing surface.


It looks like this when you're dragging the dialog.


Now let's add some more associations among the classes.


You can pause here to catch up.


When you're done, your finished diagram should look approximately like this.


Now, let's add two methods or operations.


This is done just like adding Attributes to the classes except you select


operation from the context menu and add the following methods as shown.


You can pause to do this.


The final result should look like this.


Now, don't forget to save the model.


This is a long session.


You did a lot of work but you've come a long ways too.


You've seen how the basics of how to build a class model in Rhapsody.


This gives you a basic understanding of how an object oriented model works.


In our next lesson,


we'll use what we build here to create a sequence diagram and it won't take so long.


Thank you very much.


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