Once you have started your carreer as a software engineering it is almost imposible not to hear about design patterns, and the more that you go further your career the more important this topic becomes.

In order to understan what a design pattern is, we must see the definition of pattern, a pattern can be describes as a repeated or singular way in which particular things are done, what this definitions ways is that a pattern is like a serie of steps that ,must follow an order.

We are going to make a bowl of cereal

• First put the bowl
• Then put the cereal
• Then pour the milk in the bowl
• Finally enjoy

This is the most common way to make a bowl of cereal, because in this way all the cereal gets milked, even though there are other ways to make a bowl of cereal, like pouring the milk before, the result may not be the same, or at least a little bit different than normal.

Thats basically how a pattern works, and it is no different when we talk about design patterns in computer science, as we previously saw, design patterns are must not define the final product, but a serie of instructions that may lead you to the final product, defined as repetable solutions that allows users to solve common problems.

One of the best things about design patterns is that because they are meant to solve common problems, and common problems occur quite often, these patterns are always improving, which helps to make them more usefull.

There are two types of design patterns: structural or behavioral

Behavioral

This kind of patters focus in the object comunication patterns, which focuses on functions instead of rules, most commonly followed by:

• Chain
• Iterator
• Mediator
• Observe
• State
• Visitor

Structural

On the other hand, structural focuses on object and class compositions, in which it is defined the ways to compose new objects in order to obtain new functionalities

Some of the different methods in structural design are:

• Separating object’s interface from it’s imlementation
• Compose objects intro tree structures to easy manage
• Add responsabilities to objects
• Creating classes that represents a subsystem

My personal opinion

This is something that I definetely have struggled with, because when you are working in a colaborative project the way that your mind works is not the same as your partner, which means that most likely the way that you will work with the code is not going to be the same, this because you follow diferent design patterns, so it can turn out into an spaguetti code, in those cases I think that is really smart to have these kind of programmin strategies because with these design patterns you can divide the main functionality of the software into pieces that can be treated as individuals and finally merge them to obtain a full-well organized software, this is definetely a proccedure that I would consider using next time I’d have a software project.

If you want to know a little more about design patterns check out this video

REFERENCES

Object Oriented Design. (n.d). Design Patterns. Retrieved from: https://www.oodesign.com/

Source Making. (n.d). Design Patterns. Retrieved from: Souhttps://sourcemaking.com/design_patterns

In order to talk about modeling languages we firt define what a language is, language is a neurotipical process that allows people to organize and analyse diferent patterns, these will lead people to understand and replicate what others do, as an example a baby hears that everyone calls the woman who gave him birth «Mom», so he analises and replicates the sound, this how a language works.

The diference here is that the topic that I will explain in this post has nothing to do with babys, instead we will see how a computer will analyse and compare situations in order to create proccedures or develop a diferent context.

A modeling language is a graphical or textual computer language that is used to design models of new software or system.

Modeling is an integral part of the software development process, this process allows to user to understand how the data works, the sofware structure and the states that the software will take. Worldwide there are a lot of modeling languages but the most common of all is known as UML, Unified Modeling Language, which describes the software with all of their functions and how the software communicates.

In other hands Textual Modelin Languages are quite popular nowadays, this because they are formalized natural languages that has the capability to describe the whole functionality of the sofware, this Modeling Language has to follow these simple requirements.

• Easy to read: No matter who, everyone should be able to understand the main functionality of the software by reading the TML
• Not ambiguous: If the TML is confusing it may cause some misunderstandings about the functionality of the software
• Describe levels of abstraction: This is one of the main characteristics of the modeling language because it should be able to describe the software in a logical and physical enviroment

The main diferences between a Graphical Modeling Language, and a Textual Modeling Language is the way that each one describes the software

Graphical

Graphical shows how the software communicates and and it’s method elements

Textual

Textual shows every aspect of the item, including it’s characteristics

My opinion

I can easily say that I have used some of this modeling languages, but as I as I said, just some of them the one that I have the most experience with is definitely the UML, this because in my opinion is the best way to describe what the software can do, how does the software is connected, how the communication between methods work, the elements of the method and how does they work as one simple software, by the other hand I have never used any TML, not because I did not need to use them, instead because I have not known them yet, of course there are pros and cons about every model, but my recomendation is that feel free to use the one that you are more comfortable with, this because no matter what you are the one who is going to make the model, and is your project the one that needs to be explained in it’s more simple form.

References:

Martin, M; Macek, O (2012) On General-purpose Textual Modeling Languages, recovered from: http://ceur-ws.org/Vol-837/paper10.pdf References:

Imagine that you have a project that you want to build, the only problem is that you don’t know when or how to start it, this when you can use Use Cases procedure.

Use cases is a method that allows the users to identify, organize and clarify the requirements of their projects. This method describes step by step what the user needs to accomplish in order to get a successful project, in each step there is a specific goal to accomplish and how to avoid mistakes, this method allows the user to decidir which path will he choose to create his product.

• Organize the requirements
• A sequence of follow up actions
• Multi use model, if it worked for something it should work for something else
• The vision of the goal of the product

How to use it

Fist of all the user needs to have a clear idea of what he is trying to achieve, Secondly, describe the process that he will follow in order to get the product, Thirdly, the user must check and re-check the product in order to give maintenance to the system, and Finally, repeat the process until the product achieves the main goal, previously established.

I will try to give an example of how can a use cases model can be used, We are going to use a normal shopping situation as an example

First of all describe the users, and their responsabilities.

• Customer: look for an item, purchase item, cancel purchase.
• Seller: look for an item, add item, delete item, ship item.

Once you have described the actions that can perform the users, now you must create a model with this actions, and relate the actions to the users allowed to realize them, this model should look like this.

Personal Opinion

This a nice way to represent the actions that the users are allowed to perform once your project is done, it is basically what your project must be available to perform and verifies the permisions and restrictions of users, in every big project development there must be a document that describes the main functionality of the project, the requirements, the goals, the process that needs to be followed in order to create a project, I consider this model to be an easy option to explain the permitions of the users, this is definetely an easier way to see the users potential.

At the moment I am working on a tennis project for one of my subjects, and in this project we must implement every topic that I am posting, for this example I woul like to show you how our use cases model looks like, this project allows the users to play tennis, the thing is that uour project is basically a datin app, just instead of dating users play tennis and get fun.

If you want to know more about our project check my colleage Francisco’s post.

References

Brandenburg, L. (s.f) How to write a use case. Bridging the gap. Retrieved from: https://www.bridging-the-gap.com/what-is-a-use-case/