In this tutorial, we'll go over how to use and understand React Hooks. This article is an extension of article how-to-manage-state-with-hooks-on-react-components. It has been expanded with other Hooks and logic and Lessons Learned.
Here we create a simple product page with a shopping cart (see image 2). The shopping cart represents the memory (or the 'state') of the product page. The state generally refers to application data that must be tracked.
If you're developing web apps using Ruby on Rails, you probably already know that Rails is an MVC (Model-View-Controller) framework, which means that you have your Models responsible for data, Views responsible for templates, and Controllers responsible for request handling. But the bigger your app gets, the more features it has - the more business logic you will have. And here comes the question, where do you put your business logic? Obviously, it's not viewed that should handle it. Controllers or Models? That will make them fat and unreadable pretty soon. That's where Service Objects come to the rescue. In this article, we'll find out what are Rails Service Objects and how you can use them to make your app cleaner and keep it maintainable.
Let's say you have a project for handling cab trips; we'll take a look at the particular controller action, which updates trip records. But it should not only update trips based on user input params (e.g., starting address, destination address, riders count, etc.), but it should also calculate some fields based on those params and save them to the database. So, we have a controller action like this:
Have you noticed how Google Maps predicts the estimated time of your arrival more and more precisely? How has Siri become better and better at understanding your requests? Have you ever bought Cryptocurrency or NFT? Maybe you know someone who has. All these technologies are a small glimpse of the upcoming Web 3.0 - the newest iteration of the Web based on technologies such as blockchain and machine learning.
The web is standing for "World Wide Web," which is the primary information retrieval mechanism on the internet. Terms the Web and the Internet can often be used interchangeably. In the history of the Internet, we had 2 phases of its evolution. The original Web 1.0. was the very first version of the Internet that lasted from 1991 till 2004. Web 2.0. is the current version of the Web that we all are familiar with. Web 3 or Web 3.0 is the next step in the evolution of the Internet. Let's take a deeper dive into the Web's history to get a better understanding of what's to come next and look at the opportunities and challenges that Web 3.0 creates.
A Java interview will most likely involve a scenario in which candidates will have to demonstrate their logical and programming skills, as well as their experience, as part of their evaluation of the candidate. Among the most common questions asked in interviews is "Can you write a palindrome program in Java?" This is also one of the most challenging questions to answer. Palindromes are nothing more than numbers or strings that remain unchanged when reversed, while a non-palindrome is the opposite of it. It is obvious that when letters are reversed, they form mirror images of one another. Originally from the Greek language, palindromes are numbers, words, or sets of characters that are spelt the same way forward and backwards. Among the many examples of palindromes are 686, 1401042, 95359, 7007, Malayalam, Radar, MAAM, Radar, Level, etc. Upon reversing the letters, it is evident that they form mirror images of one another. With the remainder and division operators in Java, we can create a code that checks if a particular number is a palindrome or if it is not.
In this article, we will learn how to check whether the input number is a palindrome or a number that is not a palindrome. Here we will discuss what is palindrome, what is palindrome number, as well as a sample palindrome program in Java. The first step to understanding Java's implementation of palindromes involves understanding the concept of palindromes.
I love ClojureScript. The language, the look, and the feeling when I type the code to make my React components with it make me stay up all night. It actually did yesterday when I try to pick up on a friend set up and get back to a modern environment to do my coding.
Let’s walk through the first few steps to get to a setup with a React counter in ClojureScript, all this with live code reloading from VSCode.
Some time ago, I wrote the Introduction to Spring Data Elasticsearch 4.1 article. As I promised, I want to continue with a search feature. More specifically, the topic is its pagination part. Therefore, this article has these goals:
Note: I recommend reading the previous article in order to understand the City domain which is used below. It's not needed from the technical point of view, but it can help to understand the presented examples more.
In this article, let’s see how to use transient variables while using javascript to implement Camunda external task.
Pre-requisite:
You’ve developed an amazing API product. Fantastic. But that’s just the beginning of your journey. Starting an API-first company brings with it a whole host of unique challenges for you to face along the way. Based on my own experience of founding an API-first company, I've shared some insights below to help you avoid some of the pitfalls and make the most of the opportunities that lie before you.
“API-first” can mean different things to different people. However, for the purposes of this article, we’re referring to companies that publish APIs as their primary product and make money by selling their APIs to other businesses.
Becoming a professional software developer typically requires 5 years of learning before you’re even a junior developer. To understand why let’s go through everything you need to learn if you want to become a “full stack”.
The above is the minimum knowledge required to learn before you can land a job as a junior software developer. However, I have another path, allowing you to “frog leap” everything from the above list, and become a professional software developer literally in 20 minutes. And it’s arguably summed up in the slogan for Aista.
OSINT, in general, helps an organization keep tabs on public information. It also helps in reducing the potential attack surface and thus prevents breaches and leaks. For example, the following tasks are done with the help of OSINT.
In my previous article, I wrote about how we can seamlessly generate template-based documents in our javascript application using EDocGen.
As a Java developer, I have worked on creating backend applications for e-commerce and healthcare enterprises where the requirement for document generation is vast. And they have mostly done in java spring boot application. This made me think, why not write an article on the Template-Based PDF Document Generation in Java?
How can I do request-response communication with Apache Kafka? That's one of the most common questions I get regularly. This blog post explores when (not) to use this message exchange pattern, the differences between synchronous and asynchronous communication, the pros and cons compared to CQRS and event sourcing, and how to implement request-response within the data streaming infrastructure.
Before I go into this post, I want to make you aware that this content is part of a blog series about “JMS, Message Queues, and Apache Kafka”:
Personalized health records and visual tools have been a godsend for digital health management, giving users the tools to conveniently track their health on their mobile phones. From diet to weight and fitness and beyond, storing, managing, and sharing health data has never been easier. Users can track their health over a specific period of time, like a week or a month, to identify potential diseases in a timely manner, and to lead a healthy lifestyle. Moreover, with personalized health records in hand, trips to the doctor now lead to quicker and more accurate diagnoses. HMS Core Health Kit takes this new paradigm into overdrive, opening up a wealth of capabilities that can endow your health app with nimble, user-friendly features.
In this article, I will show you how to turn an app into a handy health assistant using Health Kit. The app will be able to obtain users' health data on the cloud from the Huawei Health app, after obtaining users' authorization, and then display the data to users. Hope you will find this helps.
The concept of observability was introduced a little over 60 years ago as a notion related to control theory, systems theory, and signal processing. Today, modern observability is still very much focused on looking at systems’ outputs to determine their internal states. Sprinkle in site reliability engineering, and there should be little to no performance issues in distributed systems, right? In an ideal world, yes, but in reality, there is still work to be done.
And this is where we could use your insights!
This is an article from DZone's 2022 Database Systems Trend Report.
For more:
Read the Report
In 2006, mathematician and entrepreneur Clive Humby coined the phrase, "Data is the new oil." The primary point of this comparison is to highlight that, while extremely useful, data must be extracted, processed, and refined before its full value can be realized. Now over fifteen years later, it is easier than ever to accumulate data, but many businesses still face challenges ensuring that the data captured is both complete and correct.
Nowadays, apps use device locations to provide a wide variety of services. You may want to see a user's location to show services around them, learn the habits of users in different areas, or perform location-based actions, like a ride-hailing app calculating travel distance and trip fare.
In order to protect user privacy, however, most apps request device location only when they run in the foreground. Once switched to the background, or even with the device screen turned off, apps are usually not allowed to request device location. As a result, they cannot record the GPS track of a device, which negatively affects the user experience of core functions of many apps, such as ride-hailing, trip-sharing, and exercise, all of which need to track location in real time.
What started as an experiment turned into a series of articles on FerretDB and CockroachDB. There are a lot of untapped opportunities realized by FerretDB backed by CockroachDB; some of those capabilities are computed columns with secondary indexes, partial indexes, constraints, spatial capabilities, JSONB operators, multi-region abstractions and of course correctness and consistency. Today, we're going to discuss CockroachDB multi-region capabilities and how they can help the MongoDB converts.
I am going to use the same CockroachDB Dedicated cluster from the previous article. Please refer to the previous article for the detailed steps. You can get a 30-day trial of CockroachDB Dedicated following this link.
Ethereum’s transition to Proof-of-Stake (dubbed The Merge) is easily the most significant and anticipated improvement of the blockchain network since its genesis in 2015. The Merge has been in the works for as long as Ethereum has been live, and it will occur at Total Terminal Difficulty (TTD) 58750000000000000000000, or somewhere between September 13th and 15th.
The Ethereum community, whether they are developers, stakers, or end-users, obviously have many questions related to preparing themselves for the Merge, depending on how they interact or build on top of the network.
Database migrations are a common part of any web application. They are used to update the database schema to match the application's code. In a traditional web application, the database migrations are run synchronously, which means that the application is blocked until the migration is complete. This is not ideal, as it means that the application is unavailable to users during the migration. Long past the days when stopping the service for maintenance was acceptable; we need to be able to run migrations without blocking the application.
It's easy to perform database migrations in small databases or if you have no load. But what if you have a large database and a lot of users?
