“You should not also underestimate the power of writing itself…You can lose your larger sense of purpose. But writing lets you step back and think through a problem. Even the angriest rant forces the writer to achieve a degree of thoughtfulness.”

—Atul Gawande, Better

Record what you learn has the purpose to make everyone able to memorize things for a very long time. Using this pattern, it’s not just about writing down notes in a paper and then forget about it. It is about writing down the information you need to learn and read it continuously to keep that information stored in your brain. Keeping a record of your lessons to a blog or personal wiki, it is not a bad idea at all. You decide whom you’re going to share it with, or not share it at all. As long as you write down your notes and get back to them to read or even to make improvements, your brain will be in the perfect shape of memorizing things.

This pattern made me realize that taking notes and writing the most important parts of the lesson is not the end of the learning process. Most of the time when I have to learn something new, I write pages and pages that never end, read them, and then I write a summary without looking at the notes. The problem with this is that after I am done with that lesson, I don’t really go back and read those notes, nor the summary. I wonder if I still have those notes?!

I found this pattern very useful and interesting in my career. Starting from today, I will keep track of my writings, add more details to them, and stick the date they get written, so that when I go back, I would find very organized writing that would make me go back to it over and over again. There is no better thing as reading constantly and memorizing useful information. Another important part of this pattern is that when you go back to read you realize how much things have evolved for a specific topic, and you ask yourself if you should update the original or not? In my opinion, the same as everything nowadays gets updated, writings need an update as well. As a conclusion, keep a record of your writings, the same way you keep a record of bank transactions…

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

If you are close to graduation as a Computer Scientist or Software Developer, the market for you will be huge. There are unlimited opportunities in the Tech field but should really be prepared for that. How do you see yourself in the professional world? Where do you see your starting point, and what are your future goals? An inexperienced Software developer, you have to be an apprentice, and following the long way of this journey, you will be a master, unless something goes wrong – like really wrong.
Reading “Apprenticeship Patterns” by Adewale Oshineve and Dave Hoover, will give you the first jump on the “Software Craftsmanship” world.

The term Software Craftsmanship is used to illustrate the skills you need to be successful in this journey. Being a Software Craftsman, you don’t need to have coding skills, you need creativity, you need to build your crafts, design your ideas, solve the problems avoiding complexity. Sounds fun, right? Yes, it is actually fun if you enjoy it, and if you know how to start from point zero. Imagine if you are a baby: you need to learn how to walk before traveling the world. You need to learn how to talk and read before being a scientist. So, you must be an Apprentice and follow the pathway that is important for you. One step at a time, learning from your masters and applying your skills will make you jump to the next phases. However, if you need to maintain your skills you don’t need just to practice them, you should also pass them to the other people.

At this point, you will not be an apprentice anymore, you will be a journeyman! Being a journeyman does not mean that you do not need to learn anymore, you should still follow your mentors, they will still be your masters who open new doors of your mind. You will still be focused on your craft, your ability to develop your skills, to advance the complexity of your designs. As a Journeyman, you should have created your portfolio, which represents your experiences, your knowledge and your ability to be a craftsman.

Next step, you will be a master. As a master, you will be an apprentice: you will keep learning and develop your skills, you will be a journeyman: you will keep building your portfolio and expand your craftsman ability, and Master: you have to move the industry forward and pass your knowledge to the new apprentices. Being a master means that you have all the needed skills and experiences to be a true craftsman. You will have the ability to design, architect and construct your crafts.

As you go through this journey you will need to make important choices. You should always need to be careful about what you choose, money or experience. Money can give a good life, financially, but skills and experience give you more opportunity and open more doors for your future. Ready to start your journey? Good luck…

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

The Adapter pattern is easy to understand as the real world is full of adapters. The general idea of an adapter in software development is identical to the one in the physical world. If you have been to different countries, you probably recognized that a lot of them are using differently shaped power sockets. Quite often, they are shaped in a way that the plug of your electrical device doesn’t fit. So, how do you connect the charger of your mobile phone or laptop to these power sockets?

The answer is simple. You get an adapter which you can put into the power socket and then you put your plug into the other end of the adapter. The adapter changes the form of your plug so that you can use it with the power socket. In that example and in most other situations, the adapter doesn’t provide any additional functionality. It just enables you to connect your plug to the power socket. The Adapter Pattern applies the same idea to object-oriented programming by introducing an additional adapter class between an interface and an existing class. The adapter class implements the expected interface and keeps a reference to an object of the class you want to reuse. The methods defined by the interface call one or more methods on the referenced object and return a value of the expected type. By doing that, the adapter class fulfills the expected contract by implementing the interface and enables you to reuse existing, incompatible implementations.

The Adapter Pattern is an often-used pattern in object-oriented programming languages. Similar to adapters in the physical world, you implement a class that bridges the gap between an expected interface and an existing class. That enables you to reuse an existing class that doesn’t implement a required interface and to use the functionality of multiple classes, that would otherwise be incompatible.

One advantage of the Adapter Pattern is that you don’t need to change the existing class or interface. By introducing a new class, which acts as an adapter between the interface and the class, you avoid any changes to the existing code. That limits the scope of your changes to your software component and avoids any changes and side-effects in other components or applications.

Thank you for reading!

Reference

https://dzone.com/articles/adapter-design-pattern-in-java

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

The Singleton pattern encapsulates a shared resource within a single unique class instance. This instance arbitrates access to the resource and storage-related state information. A class method provides the reference to this instance, so there is no need to pass the reference around Any object that has access to the Singleton’s class header can use the Singleton.

This design pattern defines the structure of a class that can have only one instance. A Singleton encapsulates a unique resource and makes it readily available throughout the application. The resource might be hardware, a network service, a persistent store, or anything else that can be modeled as a unique object or service. Singletons may often be modeled as a server within the application that accepts requests to send, store, or retrieve data and configure the resource state.

Implementation

Implementation of the Singleton pattern often typically creates a single object using the factory method, and this instance/object is called a shared instance in most cases. Since the access to the instance is passed on though a class method, the need to create an object is eliminated.

Pros and Cons

Singletons are not the answer to every problem. Like any tool, they can be short in supply or can be overused. Some developers are critical of Singletons for various reasons. We will examine this critique and discuss ways to address them briefly. The criticisms, for the most part, fall into two categories:

Singletons hinder unit testing: A Singleton might cause issues for writing testable code if the object and the methods associated with it are so tightly coupled that it becomes impossible to test without writing a fully-functional class dedicated to the Singleton.

Singletons create hidden dependencies: As the Singleton is readily available throughout the code base, it can be overused. Moreover, since its reference is not completely transparent while passing to different methods, it becomes difficult to track.

To avoid these complications, when considering the Singleton pattern, you should make certain that the class is a Singleton. Also, while thinking of designing the Singleton design pattern, keep testing in mind and use dependency injection whenever possible, which means: try to pass the singleton as a parameter to the initializer whenever possible.

Thank you for reading, please share it if you found it useful!

Reference

https://www.geeksforgeeks.org/singleton-design-pattern-introduction/

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

Motivation:

Sometimes we need the ability to control the access to an object. For example, if we need to use only a few methods of some costly objects we’ll initialize those objects when we need them entirely. Until that point, we can use some light objects exposing the same interface as the heavy objects. These light objects are called proxies and they will instantiate those heavy objects when they are really need and by then we’ll use some light objects instead.

This ability to control the access to an object can be required for a variety of reasons: controlling when a costly object needs to be instantiated and initialized, giving different access rights to an object, as well as providing a sophisticated means of accessing and referencing objects running in other processes, on other machines.

Consider for example an image viewer program. An image viewer program must be able to list and display high resolution photo objects that are in a folder, but how often do someone open a folder and view all the images inside. Sometimes you will be looking for a particular photo, sometimes you will only want to see an image name. The image viewer must be able to list all photo objects, but the photo objects must not be loaded into memory until they are required to be rendered.

Intent:

The intent of this pattern is to provide a placeholder for an object to control references to it.

Implementation:

The participants classes in the proxy pattern are:

Subject – Interface implemented by the realSubject and representing its services. The interface must be implemented by the proxy as well so that the proxy can be used in any location where the RealSubject can be used.

Proxy – Maintains a reference that allows the Proxy to access the RealSubject. Implements the same interface implemented by the RealSubject so that the Proxy can be substituted for the RealSubject. Controls access to the RealSubject and may be responsible for its creation and deletion. Other responsibilities depend on the kind of proxy.

RealSubject – the real object that the proxy represents.

Applicability:

The Proxy design pattern is applicable when there is a need to control access to an Object, as well as when there is a need for a sophisticated reference to an Object. Common Situations where the proxy pattern is applicable are:

Virtual Proxies: delaying the creation and initialization of expensive objects until needed, where the objects are created on demand.

Remote Proxies: providing a local representation for an object that is in a different address space. A common example is Java RMI stub objects. The stub object acts as a proxy where invoking methods on the stub would cause the stub to communicate and invoke methods on a remote object found on a different machine.

Protection Proxies: where a proxy controls access to RealSubject methods, by giving access to some objects while denying access to others.

Smart References: providing a sophisticated access to certain objects such as tracking the number of references to an object and denying access if a certain number is reached, as well as loading an object from database into memory on demand.

Related Patterns:

Adapter design Pattern – The adapter implements a different interface to the object it adapts where a proxy implements the same interface as its subject.

Decorator design Pattern – A decorator implementation can be the same as the proxy however a decorator adds responsibilities to an object while a proxy controls access to it.

Reference

https://javapapers.com/design-patterns/proxy-design-pattern/

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

AngularJS is an open source web application framework. It was originally developed in 2009 by Misko Hevery and Adam Abrons. It is now maintained by Google. Its latest version is 1.2.21. AngularJS is a structural framework for dynamic web applications. It lets you use HTML as your template language and lets you extend HTML’s syntax to express your application components clearly and succinctly. Its data binding and dependency injection eliminate much of the code you currently have to write. And it all happens within the browser, making it an ideal partner with any server technology.

GENERAL FEATURES:

• AngularJS is an efficient framework that can create Rich Internet Applications (RIA).
• AngularJS provides developers an option to write client-side applications using JavaScript in a clean Model View Controller (MVC) way.
• Applications written in AngularJS are cross-browser compliant. AngularJS automatically handles JavaScript code suitable for each browser.
• AngularJS is open source, completely free, and used by thousands of developers around the world. It is licensed under the Apache license version 2.0.

Overall, AngularJS is a framework to build large scale, high-performance, and easy to maintain web applications.

CODE FEATURES:

Data Binding – It is the automatic synchronization of data between model and view components.

Scope – These are objects that refer to the model. They act as a glue between controller and view.

Controller – These are JavaScript functions bound to a particular scope.

Services – AngularJS comes with several built-in services such as $http to make an XML Http Requests. These are singleton objects which are instantiated only once in app.

Filters – These select a subset of items from an array and returns a new array.

Directives – Directives are markers on DOM elements such as elements, attributes, CSS, and more. These can be used to create custom HTML tags that serve as new, custom widgets. AngularJS built-in directives such as ngBind, ngModel, etc.

Templates – These are the rendered view with information from the controller and model. These can be a single file (such as index.html) r multiple views in one page using partials.

Routing – It is concept of switching views.

Deep Linking – deep linking allows to encode the state of application in the URL so that it can be bookmarked. The application can then be restored from the URL to the same state.

Dependency Injection – AngularJS has a built-in dependency injection subsystem that helps the developer to create, understand, and test the applications easily.

ADVANTAGES OF ANGULARJS:

• It provides the capability to create Single Page Application in a very clean and maintainable way.
• It provides data binding capability to HTML. Thus, it gives user a rich and responsive experience.
• AngularJS code is unit testable.
• AngularJS uses dependency injection and make use of separation of concerns.
• AngularJS provides reusable components.
• With AngularJS, the developers can achieve more functionality with short code.
• In AngularJS, views are pure html pages, and controllers written in JavaScript do the business processing.

DISADVANATAGES OF ANGULARJS:

Not Secure – Being JavaScript only framework, application written in AngularJS are not safe. Server-side authentication and authorization is must to keep an application secure.

Not degradable – If the user of your application disables JavaScript, then nothing would be visible, except the basic page.

References:

https://angularjs.org/

https://en.wikipedia.org/wiki/AngularJS

https://www.w3schools.com/angular/angular_intro.asp

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

REST is a term coined by Roy Fielding to describe an architecture style of networked systems. REST is an acronym standing for Representational State Transfer.  It represents the state of database at a time. REST is an architectural style which is based on web-standards and the HTTP protocol. In a REST based architecture everything is a Resource. A resource is accessed via a common interface based on the HTTP standard methods. You typically have a REST server which provides access to the resources and a REST client which accesses and modifies the REST resources.  Every resource should support the HTTP common operations. Resources are identified by global IDs. REST allows that resources have different representations, e.g., text, XML, JSON etc.

HTTP Methods

The PUT, GET, POST and DELETE methods are typically used in REST based architectures. The following table gives an explanation of these operations:

POST –> INSERT (adds to an existing resource)

PUT –> UPDATE (overrides existing resource)

GET –> SELECT (fetches a resource, while the resource is never changed via a GET request)

DELETE –> DELETE (deletes a resource)

USE NOUNS BUT NO VERBS IN PATH/URI:

USE PLURAL NOUNS

Do not mix up singular and plural nouns. Keep it simple and use only plural nouns for all resources.

/cars instead of /car

/users instead of /user

/products instead of /product

SOME TIPS FOR YOU:

• Use PUT, POST and DELETE methods instead of the GET method to alter the state. Do not use GET method or Query parameters for state changes.
• If a resource is related to another resource use sub resources.
• Both, client and server need to know which format is used for the communication. The format has to be specified in the HTTP-Header.
• Make the API Version mandatory and do not release an un versioned API.
• Use a simple ordinal number and avoid dot notation such as 2.5
• Use a unique query parameter for all fields or a query language for filtering.
• Allow ascending and descending sorting over multiple fields.
• Use limit and offset. It is flexible for the user and common in leading databases.
• To make the API experience more pleasant for the average consumer, consider packaging up sets of conditions into easily accessible RESTful paths.

References:

https://en.wikipedia.org/wiki/Representational_state_transfer

https://restfulapi.net/

https://www.smashingmagazine.com/2018/01/understanding-using-rest-api/

Thank you for your time!

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

Anders Hejlsberg is known as the creator of TypeScript. On 2010, he and his team began developing TypeScript, and in 2012 they released TypeScript 0.8 for the first time. There were several versions of TypeScript released since 2012. The last version announced is TypeScript 3.2 RC, which is the release candidate of the next version. According to Anders Hejlsberg, JavaScript is TypeScript, but TypeScript is not JavaScript, which makes TypeScript a superset of the JavaScript language. That means that any valid JavaScript code is also valid TypeScript code.

TypeScript has additional features and does not exist in the current version of JavaScript, supported by most browsers out there. In TypeScript, we have this concept of strong or static typing. If you have worked with languages like C# or Java, you know that in these languages when we define a variable, we need to specify the type of that variable. In TypeScript typing is optional so we don’t have to use this feature. But using this feature makes our applications more predictable and it also makes it easier to debug them when something goes wrong. Typescript also brings Object-oriented features that we have missed in JavaScript for a long time. We have the concepts of classes, interfaces, constructors, access modifiers like public and private, fields, properties, generics, and so on. Another benefit of using TypeScript is that with TypeScript we can catch errors at compile time instead of the runtime, of course not all errors but a lot of them. There is a compilation step involved, and when we compile with TypeScript code, we can catch these errors and fix them before deploying our application. And finally, another benefit of using TypeScript is that we get access to some great tools out there. One thing that I personally love about TypeScript is the autocomplete suggestions that we get in our code editors as we are coding, like Atom and Visual Studio Code.

TypeScript is a beautiful language but the browsers that we use every day don’t know TypeScript, and it is very unlikely that the browsers are going to support TypeScript in the future. So, we need to compile or more accurately Transpile our TypeScript code into JavaScript code.  This is part of building an application. Whenever we build an application TypeScript compiler kicks in and it Transpiles TypeScript code into JavaScript code that browsers can understand.

References: https://en.wikipedia.org/wiki/TypeScript,

https://channel9.msdn.com/posts/Anders-Hejlsberg-Introducing-TypeScript,

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.