Instead of using class constructors or
new keyword to create an object of a class, we can abstract this process. So, we can determine the type of object at run-time, by the time of generating that class object. The implementation seems like Factory Method, but simpler than Factory Method. This simple Factory is not treated as a standard GoF design pattern, but the approach is common to any place where we want to separate the code that varies a lot from the code that does not vary.
In this tutorial, grokonez shows you how to do it in NodeJs.
[Continue reading…] “How to implement simple Factory Pattern in Node.js”
In the tutorial, we will show how to find an element in a List Object with Java APIs and Google Guava library.
[Continue reading…] “Java – How to find an element in a Java List Object by Examples”
Singleton is object that can have only a single, unique instance, with a single point of access. Node.js module system provides simple way to implement Singleton using
module.exports. Module will be cached when it is accessed using
require() statement. So our module is merely a cached instance although it behaves like a Singleton.
In this tutorial, we’re gonna look at ways to implement this kind of Singleton in Node.js:
- Singleton Object
- Singleton Class
[Continue reading…] “How to implement Singleton in Node.js”
In many cases, creating a new instance is a costly operation. Fortunately, we can copy or clone an instance of an existing one instead of creating from scratch. This approach can be done by using Prototype Pattern, one of Creational Patterns.
[Continue reading…] “Java Prototype Pattern tutorial with example”
In the tutorial, we build a SpringBoot RestAPIs example that post/get data with
java.util.Date time and save it to MySQL/PostgreSQL database using Spring JPA. Working with Java Date Time is an exciting part but also not easy task, fortunately we have the supporting from utilities of Jackson lib, now the job can be done in an easy way.
Let’s do details by steps!
[Continue reading…] “Java Date Time – How to build SpringBoot RestApi – Post/Get request with Java Date Time using Jackson and Make Query with Spring JPA example”
Building user authentication is not easy, in almost case, it’s complicated. Fortunately, Django has a powerful built-in User authentication that helps us create our Authentication system fast. By default, the User model in Django
auth app contains fields: username, password, email, first_name, last_name… However, using our own custom user model allows us deal with user profile more comfortably. For example, what if we want to add more fields: full_name or age?
In this tutorial, we’re gonna look at way to customize authentication in Django (version 2.1) using subclass of
AbstractUser. All User authentication data will be stored in MySQL/PostgreSQL database that we’ll show you how to config the datasource.
It will be very interesting. Let’s go through the steps.
[Continue reading…] “Django Authentication – How to build Login/Logout/Signup for custom User”
In the tutorial, We discuss how to Sort Java List Objects by Date property with difference Date types:
LocalDateTime. Java provides 2 main approaches for sorting Java List with Comparator:
java.util.Collections.sort(List list, Comparator< ? super Customer> c): sorting the specified list according to the order providing by the specified comparator.
java.util.Collection.stream().sorted(Comparator< ? super T> comparator): returning a stream consisting of the elements of this stream, sorted according to the provided Comparator.
Let’s do more details with Java syntax examples (Java 7 and Java 8) by descending and ascending sorting order.
[Continue reading…] “How to Sort Java List Objects by Date property with Examples”
In the tutorial, we will discuss how to Sort an Array with Java in ascending and descending order.
java.util.Arrays class provides a lot of Methods to sort an Array with difference types:
- With Primitives Array, We use the method such as:
static void sort(int a).
- With String or Objects Array that implement
Comparable, We use method:
static void sort(Object a).
- With Custom Object Array that no implement
Comparable, We use method:
sort(T a, Comparator< ? super T> c).
Let’s do more details with Java Array Sorting.
[Continue reading…] “How to Sort an Array in Java with Examples”
In this tutorial, we’re gonna look at way to upload file in Django using Django
ModelForm and save its information to MySQL Database. We also have UI to view list of uploaded items and function to delete specific file.
Related Post: Simple way to upload file in Django
[Continue reading…] “Django – How to upload, view, delete file using ModelForm and MySQL”