Author Archives: cradkowski

REST APIs – A Few Good Guidelines

Today I will be looking at an article that examines five basic guidelines when creating a REST API program. I thought that after spending over a month on our final project creating a REST API backend it would be good to review some good practices for creating these REST APIs. The article gives five basic guidelines to follow and a brief background on each of the guidelines. The five guidelines are: name and case conventions for URIs, the different HTTP methods, HTTP headers, query parameters, and status codes. Some of these topics were a refresher from what we’ve already been taught, such as some of the HTTP status codes, and others were new such as the query parameters or case conventions. I especially thought the name and case conventions for the URIs was interesting. I don’t think I have reviewed naming conventions in coding in a couple of years, I usually use camel case for everything since I mostly write in Java. But I have been wondering what was the best practice for endpoints since I remembered code with HTML being more case sensitive. Also, with using different naming schemes instead of just using verbs that describe the method as in Java. I will keep in mind going forward to use the spinal-case method when creating endpoints. The HTTP methods section was fairly straightforward with what I already know, and the use cases for most of them are the same, but it does have a couple of additional methods I haven’t seen before such as HEAD or OPTIONS. The HTTP headers section was interesting, giving definitions and names for the different types of headers you use for different requests. The query parameters section was the most interesting and something that I haven’t come across yet working with REST. The status codes were familiar too, I have mostly used OK, CREATED, and NOT FOUND in my endpoints. Although I will start using NO CONTENT when performing a deletion endpoint instead of just 200-OK, as this seems to be the more proper response code. The same with using a 400 error of BAD REQUEST instead of just giving everything a 404-NOT FOUND error when an invalid request is made or an item is not available. In the future when working with REST I will keep in mind these simple guidelines from this article, especially in regards to case conventions for endpoints and with using appropriate status messages.

Source: https://dzone.com/articles/5-basic-rest-api-design-guidelines

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

The Iterator Design Pattern

Today I learned more about the Iterator Design Pattern and how it specifically applies to Java. The reason for choosing this topic is that during my project and talking with others the Iterator has come up a number of times throughout this semester. Now, I already knew about the Iterator in Java from taking Data Structures, but I never realized it was a design pattern before this course. The Iterator is actually a Gang of Four design pattern and it is classified as a behavioral pattern with object as the scope (GoF 257). The article gives a short summary of the iterator pattern and the reason it is used in Java. It is basically a way of accessing elements in a collection in order without having to know about the internal representation of the structure, a nice way of using abstraction. The author then gives a nice simple example in Java of how to use the Iterator pattern to access a collection of elements. He does this by creating a basic shape POJO with an id int and String name and stores them in another class that is an array of shapes. He then creates an Iterator class that defines the next element and if there is another element after the current one. This may be my favorite design pattern I’ve seen yet. It is simple to implement, but yet effective at its purpose, especially the way this article showed its implementation. I really like that once you’ve created an iterator for a type, all you need to do is pass in a collection of elements to it in order to process it. When I was working on the backend for my project I realized the need for something like an Iterator, especially with all the endpoints that were looping through the whole database. I wish I had implemented this so that I did not have to keep rewriting conditions to check that the data wasn’t out of bounds. In the future when I create my own programs with collections of elements I will make sure to implement an Iterator so that I can easily cycle through the data without having to worry about how to do it or constantly bounds checking the collection.

Source: https://www.javacodegeeks.com/2015/09/iterator-design-pattern.html

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

Using Swagger for API Documentation

As we are nearing the end of the semester and about to finish our projects, I’ve been thinking more about the documentation process for the different parts including the frontend and backend. With this in mind, today I found a great topic about documentation generation for REST APIs with a tool called Swagger. I’ve never heard of Swagger before today, but it is a useful framework that allows for testing, documentation, and other useful features for building APIs. This post shows a quick little tutorial of how to implement Swagger for documentation generation with a Spring Boot project that is very similar to my project and the example REST API order system we have been using. It is a relatively simple process that includes adding the necessary dependencies for Swagger and adding a controller class for it, then all you have to do is just add the necessary documentation statements for each controller and requests within the controllers. The end result is a very nice-looking HTML page that displays a well formatted layout which includes the documentation for your API backend with a graphical display for each request and all the information associated with the request such as body and return information. Now as I was reading this article and this new way of creating documentation, I was comparing it to the way we’ve been doing it so far with a simple table written in Markdown for all of our API endpoints. The output of doing it in Markdown was nice but writing it was a tedious task with the formatting of the table. I much prefer the simplicity that Swagger allows you when adding a new endpoint. I also like the final product that Swagger produces a lot more than the simple Markdown document. In the future if I am creating another Spring Boot project, I am going to try to use Swagger from the start for documentation instead of using a Markdown document with a table for a basic readme as it appears that using Swagger makes adding new endpoints much less tedious with formatting. I would also like to try to add this to my current project if there is enough time, and also see if it is possible to use it with Angular too.

Source: https://dzone.com/articles/swagger-generation-with-spring-boot

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

Processing JSON Data with Jackson

The article that I read this week is about processing JSON data with Jackson. I thought this would be a good article to read after using JSON data a lot this week for processing input and output in our final projects, and since Spring Boot uses Jackson as the way for processing JSON. I wanted to learn more about how this works, especially after getting some errors when trying to pass in certain data types this week (particularly Calendar objects). This post goes over how to read and write JSON data to and from Java objects using Jackson for data binding. It does this by creating an example POJO to use for input and output. It creates a basic employee with the fields of name, ID number, address and other typical fields, it also has an object within an object by using an address within Employee that contains a street, city, and zip code. The article creates an example of this in a JSON input file and creates the necessary Java classes and then implements the Jackson methods (such as ObjectMapper) for databinding and outputting Java input as a JSON file.

I think that it was interesting to see how to do this with the Jackson implementation as a seemingly more proper method of converting JSON to Java objects and the other way around. Especially after spending the past week creating and getting our project to pass similar data back and forth between JSON and Java. It does seem out of the ordinary to me that both of the example classes don’t use constructors, instead using just set methods to create the object, but that’s how this implementation is supposed to work with Jackson. I particularly liked the Tree Model implementation in the article and was not aware that this was a way of processing JSON data. This article has definitely made me think more about the different ways of processing JSON data with web applications and REST APIs and the best practices to use when doing this, especially with larger, serious implementations for applications. If time permits for our final project, I would like to try and do a similar implementation in this article for our JSON processing. By doing this, it would make adding new objects to the database a lot cleaner (especially without needing a constructor) in the implementation than it currently is.

Source: https://dzone.com/articles/processing-json-with-jackson

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

The Abstract Factory Design Pattern

This post on DZone talks about the abstract factory design pattern and gives an example implementation in Java using geometric shapes. This pattern is similar to the simple factory with the idea of constructing objects in factories instead of just doing so in a client class. It differs in that this abstract version allows you to have an abstract factory base that allows multiple implementations for more specific versions of the same original type of object. It also differs in that you actually create an instance of a factory object instead of just creating different objects within the factory class as in the simple factory.

I like the concept of this pattern more than just having a simple class that creates multiple instances of different objects such as the simple factory. I also like how the design allows you to have multiple types of objects that can split off into different more specific types, such as how the example Java implementation has 2D shapes and 3D shape types and factories for each kind. The design appears to be efficient, especially in the implementation example, only creating a factory for a type of object when it matches a specific type in the client call. Like the other factory pattern, you can also easily implement other design patterns for the object itself such as a strategy or singleton, which further would improve the final outcome. Another aspect of this pattern that I like is that the client itself is not creating the objects, it just calls the factory get method from a provider class that sits between the factory and the client.

I definitely like this pattern and will certainly consider using it the next time I have to create a program with many different variations of the same objects such as shapes or ducks as seen in previous programming examples. It will be especially useful to use this design if I am trying to type check the objects from user input to make sure they are trying to create a valid type of object with the factory. Overall, I am finding that as I read more articles about design patterns, especially for many objects of the same base, I am gaining a better understanding of how to maximize the program efficiency with one or multiple design patterns.

Source: https://dzone.com/articles/abstract-factory-design-pattern

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

The Decorator Design Pattern

This week I will be looking at the decorator design pattern. This post discusses the advantages of using a decorator design pattern over inheritance in Java and gives examples of its implementation. The main advantage being a significantly less number of classes are needed when adding functionality using a decorator versus using traditional inheritance. It also mentions that the decorator should be added so that it is natively supported by programming languages. I think that this is the most interesting part of the entire article. I agree that languages, and in particular Java should start natively adding support for these design patterns. By doing this, as the article says it makes it much easier for beginner programmers to implement. I agree with this and I find that this can be challenging when you are first learning about design patterns and especially if you are starting out programming. In addition, I agree that a native implementation makes this design pattern, and others much cleaner to implement. As the example of the implementation in this article shows it would require a lot less work and code if it was implemented as they have it with just having a decorates statements instead of implements when creating a new class. I find this approach would encourage me and others to use this as it would be easy to use and not require repetitive typing, which as the article states would lead to better programs. I think this point of native support should also go beyond just this particular design pattern. I think that Java and other object-oriented languages should add native support for some of the other popular design patterns as well such as strategy or singleton. This would make it easier to experiment with different patterns earlier in the stages of learning to program and would let people see the benefits without struggling on the implementation necessarily. I would have found it much more encouraging to use one of these patterns as the article suggests if it was natively supported versus creating my own implementation based on text-book examples. Overall this article and what I’ve learned in this class have taught me to prefer using a design pattern over basic inheritance in most scenarios when building programs and that adding native support for these patterns would make it even better to use.

Source: https://dzone.com/articles/is-inheritance-dead

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

Introduction

Hello and welcome to my blog! Although this blog is being created as part of a software development course, I hope to continue using this platform to log my experiences as I continue my journey in the computer science field. Throughout the next couple of months I will be regularly posting content related to software development as I begin to explore this area of computer science.

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.