From Umass Lowell to Unified Modeling Language: A History of My Experience With the Term “UML”

Believe it or not, I have been coding since the year 2015. As the title implies, the first university that I attended (right out of high school) was the University of Massachusetts – Lowell. Interestingly enough, within my very first textbook at UML, I would be exposed to another kind of “UML” – Unified Modeling Language. At this time, Unified Modeling Language was little more than a reference at the back of the book; there was more written on the subject, but my mind was concentrating on concepts such as how to “calloc()” in C.

Fast forward 5 years, and now Unified Modeling Language takes on a larger role; it is being used for visual representations of classes and inheritance in Java code. This can be seen with the following YouTube video, “How To Make Easy UML Sequence Diagrams and Flow Charts with PlantUML” by user “Be A Better Dev”. Essentially, the video shows how Java code can be written and then turned into a UML chart for a visual representation of classes and their features.

Personally, I selected this particular video due to the fact that I enjoy using YouTube more than any other social media; this way, I can use the app for educational purposes as well as recreational ones. This nine minute video is a great way to learn about how to code for UML in a format that is digestible on a busy schedule (when at work, for example). In addition, I expect the material to be applicable to aspects of the course (such as homework and exams) due to it being another form of practice. Practice, practice and yet more practice is the most important way to retain any type of coding/programming knowledge, and UML is no different.

It’s crazy to think that something barely glossed over from my educational journey five years ago would be so prevalent in the present day. However, it makes sense; programming practices such as using an arrow (->) operator or parentheses for a method are given new meanings when working with UML. Extending this further, programming syntax can create additional effects within the PlantUML environment. For example, placing an arrow on one side or another of an entity will effect exactly where it extends from on said entity.

As a final note, I am glad that I am able to work with this newfound technology. Ever since my days at UML, I have been wondering about when my code would leave the IDE environment and tackle more “lively” features (such as a graphical interface). Thanks to Unified Modeling Language, I now have a method of making my code come to life.

Article Link: https://www.youtube.com/watch?v=xObBUVDMbQs

From the blog CS@Worcester – mpekim.code by Mike Morley (mpekim) and used with permission of the author. All other rights reserved by the author.

Docker Explained.

This week in class we’ve gone over UML Diagrams and the importance of being able to translate back and forth between writing code from the diagram and making a diagram based on the code. The professor told us to download Visual Studio and Docker, which I’m assuming will be used for the entirety of the semester. I didn’t have a single clue as to what Docker was or why it may have been needed. After a brief explanation prof told me to do a little bit of reading myself and so I did. I’m by no means not a Docker expert but the picture has become a bit clearer.

Docker is a container based application that allows you to run services independent of each other. Containers tend to be pretty compact and only carry the information neccesary for a service to work. Docker containers are created through docker images. An image is basically just a template that tells the system how to make the container. An image can consist of many layers, of which each layer is just a previous working version of the image. It’s important to note that an image is read-only. The purpose of the image is to load the container. The top most layer (when the container is created) is what the user works with, whether it’s making changes to the container itself or using the tools that come with the container. When reading about how this technology works the thought of how something like this could be secure kept on swimming through my mind but as each layer of the image is created it becomes a completely new and immutable image. I’m still not entirely sure how this works and will have to spend more time trying to understand, but for now I’ll just take it for what its worth.

Where Docker really becomes a useful tools is in its portablilty and reusabilty. For example, the use of a virtual machine to run certain programs or applications isn’t frowned upon, but it does tend to be costly in terms of using space and memory. A 500MB application could take heaps of memory to run because the guest OS and libraries would need to run before being able to use a desired application. If you wanted to run multiple instances of that application you would need to run multiple VMs. That’s where Docker delivers and gives the user what they need in terms of reusability.

Now Docker containers are not a one stop shop when it comes to solving issues. If a user is trying to use multiple servers and tries to adminstrate them only using Docker containers, they will find themselves in a pinch due to the stripped down capabilties of a container. A container only holds enough information for what actions are necessary to ensure task completion in terms of portabilty. In a scenario like this you would probably want to stick with using a VM to get the full use of the OS and all it’s resources to maintain multiple servers.

Here’s two videos that brought me up to speed on just what type of software Docker is and why it is extremely useful in just over 15 minutes. The explanations are given in a low level manner that allows people like me who couldn’t even begin to understand the concept grasp it better. I hope you enjoy the content, I did!

Containers vs VMs https://www.youtube.com/watch?v=cjXI-yxqGTI
Containerization Explained https://www.youtube.com/watch?v=0qotVMX-J5s

From the blog CS@Worcester – You have reached the upper bound by cloudtech360 and used with permission of the author. All other rights reserved by the author.

Self-Directed Professional Development Post #2

The article I’ve decided to read for this blog entry is titled, “Getting Started – An overview of Markdown, how it works, and what you can do with it.” The reason I picked this article is because it is connected to our first homework assignment. Our first homework assignment has us working with UML class diagrams and when I clicked on the web IDE on GitLab, I was brought to a file that was written in Markdown language where I would have to add my Java code and create PlantUML class diagrams. I’m not too familiar with Markdown language and since I would be interacting with it for my first homework assignment, I figured I’d do some research to learn more about it. 

The article I read starts out by defining Markdown language, “Markdown is a lightweight markup language that you can use to add formatting elements to plaintext text documents.” The article then goes into explaining why people use Markdown. I’ve learned that Markdown can be used for essentially anything: from websites, documents, notes, books, presentations, email messages, to technical documentation. I also learned that Markdown is platform independent and that the content that is created on it doesn’t get locked into a proprietary file format like Microsoft Word. 

Next, the article discusses how Markdown works. This process can be generalized into four steps:

  1. Create a Markdown file.

  2. Open the file in an Markdown application.

  3. Use the Markdown application to convert the file to an HTML document.

  4. Render the HTML document to a web browser (or another document).

During this part of the article, we also learn more about Dillinger, a Markdown editor that combines these steps. It was useful for me to learn the name of this editor because if I were to ever use Markdown for myself, I now know a common and popular editor to do so.

Lastly, the article’s main ending point is that there are many different “flavors of Markdown” and that using Markdown with one editor may provide a very different experience than using Markdown with a different editor. Many of the basic syntax may be the same but there are extended syntax elements that likely differ.

One of the biggest takeaways for me is that after I finished reading this article, I looked into other kinds of markup languages and learned how they are different from programming languages and scripting languages. Unlike programming and scripting languages, markup languages are presentation languages that do not do logical operations. It’s safe to say that, now that I’ve learned about Markdown, I feel more confident moving forward with my homework assignment (even if what I learned was going to be only a minor piece of my overall assignment).

Article: https://www.markdownguide.org/getting-started/

From the blog Sensinci's Blog by Sensinci's Blog and used with permission of the author. All other rights reserved by the author.

Understanding UML Diagram Relationships

Recently in my Software Construction, Design and Architecture class, we have been getting into UML class diagrams. The class diagrams provide an understandable system structure and the relationships among the objects. Each relationship has a distinct visual representation based on arrows:

https://en.wikipedia.org/wiki/Class_diagram#/media/File:Uml_classes_en.svg

In this case, we started using Visual Studio Code and PlantUML to model class diagrams. I referred to the UML documentation that was provided to get a better understanding of how to display each type of arrow in PlantUML.

https://plantuml.com/class-diagram

As shown above, there are three kinds of relationships that can be represented in PlantUML: Extension, Composition, and Aggregation. I am not totally familiar with the use of composition and aggregation as we’ve only been focusing on models that use extends and implements in class. I wanted to get a better understanding on how to read UML class diagrams and to be able to tell the relationships between the objects on the diagram.

With PlantUML and Markdown preview in Visual Studio Code, you can see changes to the UML diagram in real time as you modify the code. What you write in the code will reflect what shows on the diagram. You can also manually draw the relationship, which provides more customization such as arrow length, direction, etc. In addition to solid lines, you can use dotted lines to represent dependencies.

Extends is represented on a UML diagram as a solid line with an empty arrow. By writing that Class A extends Class B, you will see the diagram update show a line with an empty arrow point from Class A to Class B. Instead, you can also write Class A <|– Class B in order to display it on the diagram. When viewing the diagram alone, you can assume that Class A has access to all attributes and operations available in Class B.

Implements is represented on a UML diagram as a variation of the extension arrow, with a dotted line instead. By writing that Class A implements Interface, the diagram will be updated to show a dotted line with an empty arrow pointing from Class A to Interface. To draw an inheritance arrow on the diagram, you can write Class A <|.. Interface. When taking a look at the diagram, you can assume that Class A has access to the operations of Interface and contains the code for them.

I found the PlantUML documentation very useful as it contains basically everything you need to know about using PlantUML to create class diagrams. I also really enjoyed the functionality to modify the example diagrams to experiment with the features that you just read up on. Overall, I think that UML class diagrams are a good way to visualize a class structure. The arrows are easy to follow and help in understanding the relationship between classes.

From the blog CS@Worcester – Null Pointer by vrotimmy and used with permission of the author. All other rights reserved by the author.

What have I learned about the term “Association”?

For in-class activities of this week, we learned about modeling with UML class diagram. There were many important elements to compose a class, such as properties, operations, and association. However, my team got stuck at the “association” section, we could not clearly distinguish the different types of relationships between two classes, especially the relationship named have-a. Therefore, I thought it was a good opportunity for myself to learn more about the term “association”.

There are many articles and blogs analyzing about different types of relationships between classes. However, many of them look very complicated with a long list of different relationship types and some are very confusing. Fortunately, I found this article, entitled Association, Composition and Aggregation in Java, which finally satisfied my curiosity about “association”, because the content of this article is focused only into the definition of “association” and the analysis of its types which are aggregation and composition.

There are some key points that I have taken away after reading the article. First, association represents a relationship between two classes, depending on each situation, association can be one-to-one, one-to-many, many-to-one, and many-to-many. Second, association has two special forms, which are aggregation and composition.

For aggregation, this term is also known as has-a relationship (a weak association), which is one way relationship and each entity of the relationship can exist independently. The author also provides a simple example to describe those characteristics of aggregation, which is an Institute has-a Department, and Department has-a Student. This is one way relationship because a department can have students, but vice versa is impossible. Moreover, if the Department class is removed, the Student class can still exist independently.

For composition, this is the part-of relationship (a strong association), and the two entities are dependent to each other, which means a class (child) cannot exist without the existing of another class (parent). For this definition, the author gives an example of Book and Library, Book is part-of Library. So, if Library class is removed, Book class cannot exist. In my opinion, this example does not make sense to the part-of relationship because I think Book still can exist without Library. Therefore, I have looked for other resources to find a good example for composition. UML Association vs Aggregation vs Composition is a good resource to provide real-life examples for each conception. Like the first article, this one also focuses on the analysis of the term “association” and its two special types, aggregation and composition. According to the article, I got an example that Head, Hand, Leg are part-of Person. Thus, if Person class is removed, Head, Hand and Leg classes cannot exist. For myself, this is a perfect example to describe the term composition.

In short, I have learned a lot of information and had a clear understanding about the term “association” from the two articles recommended above. I will apply this knowledge to design relationships between classes in my UML diagrams. Moreover, I believe the articles that I choose are good resources because their content is clearly organized with good examples. In other words, I would say the two articles complement each other, so it is good if readers can pull out the best parts from each article and be able to combine them consistently.

From the blog CS@Worcester – T&#039;s CSblog by tyahhhh and used with permission of the author. All other rights reserved by the author.

Object Oriented Programming Podcast

https://podcasts.apple.com/us/podcast/object-oriented-programming/id1457402220?i=1000521718007

This podcast directly relates to our class as its main topic is Object Oriented Programming. The speaker starts off explaining that Object orientated programs are made of objects which interact with each other. These Programs are class based and in object oriented programming the objects are instances of the classes and their types are determined by said classes. Many different coding languages are used in object oriented programming such as Java, and Python because they support object programming which the speaker says is in combination with procedural programming. Most languages that support object programming are multi paradigm and contain variables which store information in a lower amount of data types for example integers which can include strings or lists. Methods used in object programming take inputs and generate outputs based on the data used which can be attributed to loops and conditionals. In object programming you can group methods into files (or modules) to help keep your program organized. The files or modules that you use will not conflict with methods or variables in a different file that may share the same name. The languages that support object programming are known for using inheritance in order to reuse previous code (classes). Classes contain the methods and data used in the code and they also contain class functions including the classes objects and instances. According to the podcasts author objects can at times correspond to things in the real world, the example he uses is when a graphics program uses shapes like circles or squares or when a shopping website uses a “shopping cart”. While some objects represent things relating to the real world other objects represent things that are more abstract like a file or a translation of some sort. Object programming is based on the concept of objects and the data they contain whether it be methods, data fields, etc. If you use an object to organize unlike classes that is not object oriented programming, you are meant to use objects to organize data that has similarities. An object being an instance of a class will contain methods which contain variables, the variables in objects still belong to the class and can also be called class variables. A variable can also be solely attached to the object and it will be called an instance variable. Class methods only have access to variables contained in the class but ther can also be instance methods which like instance variables belong to an object and they only have access to the instance variables for the specific object. Objects also provide a layer of abstraction which separates internal and external code. Objects can be called upon by the code using the method and parameters for the object, you must call a constructor to call upon an object. In some languages objects can be composed by using traits, class based languages instantiate the objects with the classes while in prototype languages there are no classes and objects are their own entities. The Podcast explains the basics of Object Oriented Programming and the different languages and components used.

From the blog CS@Worcester – Dylan Brown Computer Science by dylanbrowncs and used with permission of the author. All other rights reserved by the author.

Concurrency

For this weeks blog post i have found a website on concurrency. Concurrency is the ability of different parts or units of a program, algoritham, or problem to be executed out of order, without affecting the final outcome. A good example of concurrency can be seen on the website. For this particluar example they used the analogy of traffic. According to https://sceweb.uhcl.edu/ , the owner of the website, they say, “Parallel traffic streams on different roadways having little interaction cause few problems. Parallel streams in adjacent lanes require some coordination for safe interaction, but a much more severe type of interaction occurs at an intersection, where careful coordination is required.” (https://sceweb.uhcl.edu/). As you can see from the example the traffic patterens on two different roadways can happen simultaneously without having any issue towards their final goal, however in an intersection of the two is when issues start to arise. This is a great concept to keep in mind while coding because it nice that you can have multiple things running simultaneously but when you start to intersect the commands to run these programs is when you will start experiencing issues.

https://baptiste-wicht.com/posts/2010/05/java-concurrency-part-1-threads.html

From the blog CS@worcester – Michale Friedrich by mikefriedrich1 and used with permission of the author. All other rights reserved by the author.

Object-Oriented Programming(OOP)

This week’s blog focuses on the aspects of object-oriented programming. Understanding OOP well is essential for any developer who wants to build a high-quality software program.

In object-oriented programming, the program will be divided into many different small, manageable, reusable programs.

Each of them has its own identity, data, logic, and how it’s going to fit with the rest of the others. Usually, we may think about objects, we think about the real-world application. Something we should be able to see, touch, and feel. Then Object-Orientation was intended to be closer to the real world.

As mentioned above something is visible to all of you, like the buildings, Vehicles, Foods. Something that you can’t touch but will be able to feel or not like the time, temperature, events.

Well in programming each object has its attributes, and behavior. Objects are separate from one another as we expect them to behave. They are independent have their history and their own identity.

What are attributes in Objects?

As I said, Objects are independent due to their nature, they have their properties. For example, in the case of a vehicle, its model, color, year, and more. Their roles are to describe the current state of an object because each state is independent of the other. A vehicle might make by Toyota that’s red and another maybe blue.

How do they behave?

Behavior is certain action that the Object can perform. For example, in the case of a vehicle, it will be able to speed, stop, or horn. It’s important to remember that each has independent of the other.  To talk about Objects, Classes become inherently related.

What is a class, and how does it fit into our program?

Well, a class is a place where you can identify the behaviors and properties of an Object. The properties and behavior of an Object will be defined inside a class.

Abstraction, Encapsulation, Inheritance, and Polymorphism play a big part in object-oriented programming. This means that the focus starts on the common properties and behaviors of some Objects and left out the less important things. Separate the program into small pieces. Instead of creating different classes, we can instead create one generic class that has the common, and essential properties and behavior of those classes. use Polymorphism where an object can take the shape of many different forms. This is a very quick statement showing the stage of Object-Oriented Programming

From the blog CS@Worcester – Site Title by proctech21 and used with permission of the author. All other rights reserved by the author.

Docker

Source:

https://www.zdnet.com/article/what-is-docker-and-why-is-it-so-darn-popular/

I chose to read and write a blog post about Docker for my Week two post. I chose Docker because it is an important tool in the development community today. And because it runs in the background while we work. What Docker is actually doing, and how it accomplishes that are abstracted from us. So I wanted to learn more about how Docker works, and why so many teams are using it today.

With Docker, developers can run their applications in containers, instead of a virtual machine. A container is a unit of software that contains everything that an application needs to run on a host computer. The container is the same for all developers that access it.

Containers are an enticing alternative to Vitual machines because they have much less intensive system requirements. A VM simulates hardware and has a complete operating system, but a docker container does not. Instead, a container runs on a single linux instance. This allows developers to run multiple docker containers simultaneously. And saves the company money in server costs.

Docker containers also work well with the agile methodology of Continous Deployment. This means that developers are integrating and deploying their code quickly and regularly. Agile methodologies are becoming the industry standard. With Agile, the development process is broken into smaller units of work, that are divided amongsts small teams. Docker helps Agile teams collaborate within a shared version of their application within a container.

Docker is used by large companies in enterprise software where they are sometimes building massive applications. Docker containers make workloads more portable. As different containers can run different versions of an application, that can be running on seperate servers.

Over the summer I did an internship where I worked on enternprise .NET web applications. During my internship, we used docker containers for our Dev environment when building web applications. And we also used a Docker container for our shared PostGreSQL databases. This allowed us to work with the same sample data, in our databases, and work in the same Dev environment, before sending the next update to User Acceptance Testing.

Reading this blog has helped me understand how Docker works and why it is popular. And has given me a new perspective on why my company uses Docker. I will be using this knowledge as we are using Docker in this course, and the Software Development Capstone project. I will most likely use this knowledge in my career, as so many companies are using docker today.

From the blog CS@Worcester – Jim Spisto by jspisto and used with permission of the author. All other rights reserved by the author.

Docker

As my journey to find my very first internship as a software developer. I’ve noticed that the majority of the posts require Docker’s experience. From there, I realized that Docker is an essential tool for Software Developers and their professional careers. This blog is about Docker of what it is and also why it is necessary nowadays.

Docker is a container running time. A container is a standard unit of software that packs up codes and all their dependencies so the applicant might run quickly and reliably from one computing environment to another. Docker container is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries, and settings

The good thing about Docker is it helps developers get their application to work on every machine. Also, the abundant app’s libraries and dependencies ready to be executed make Docker even better compares to its same category competitive. Besides that, Docker is lightfast and also very easy to maintain.

Also, running applications in a container brings many benefits to both developers such as:

  • Portability: Once developers run their containerized application on their machines they also would be able to deploy it to other operations and be assured that their applications would perform the same as on their own.
  • Performance: VMs are alternative methods for developers but Docker offers much more compared to regular VMs as faster to deploy, quicker to start, and smaller footprint than ordinary VMs
  • Agility: Containers offer portability and performance help reducing time-consuming and make the process responsive and agile. Such advantages provide a better way to deliver the right software at the right time.
  • Isolation: A Docker container that contains one of the applications also includes the relevant versions of any supporting software that the developer’s application requires. If other Docker containers have different versions of the same supporting software, that is not a problem because Docker containers are independent.

Most uses of Docker make developer life simply better while developing applications. But it does not mean that Docker could entirely replace the actual Virtual Machine. VMs are still much needed if we have to have a whole operating system for each customer or the entire sandbox. VMs are still being used as middle layers when you have a big server framework and many customers that using them. Despite many good things that Docker could bring to developers, VMs still has a firm grip within the industry and development cycle.

From the blog CS@Worcester – Nin by hpnguyen27 and used with permission of the author. All other rights reserved by the author.