Tutorial by Examples: en

Many C++ libraries use enums and return/receive data using vectors that contain enums. As C enums are not Objective-C objects, Objective-C collections cannot be used directly with C enums. The example below deals with this by using a combination of an NSArray and generics and a wrapper object for th...

Service that is used for communication: import { Injectable } from '@angular/core'; import { Subject } from 'rxjs/Subject'; @Injectable() export class ComponentCommunicationService { private componentChangeSource = new Subject(); private newDateCreationSource = new Subject<Date&...

Sometimes you need to create your own Event, one that other plugins can listen to (Vault, among other plugins, does this) and even cancel. Bukkit's Event API allows this to be possible. All you need to do is make a new class, have it extend Event, add the handlers and the attributes your event needs...

JavaScript uses reference counting technique to detect unused objects. When reference count to an object is zero, that object will be released by the garbage collector. Weakmap uses weak reference that does not contribute to reference count of an object, therefore it is very useful to solve memory l...

The Builder Pattern decouples the creation of the object from the object itself. The main idea behind is that an object does not have to be responsible for its own creation. The correct and valid assembly of a complex object may be a complicated task in itself, so this task can be delegated to anoth...

Kernel manages operating system resources. User program can only access to those resources by making system calls to the kernel. System call is similar to an API of kernel, which in term, runs kernel tasks your program needs. str = "something" // run on user space x = x + 1 // run on use...

Use top command to exam CPU time allocation between user space and kernel space. Explanation: 24.8 us (user space): 24.8% of CPU time is spent on user process. 0.5 sy (system): 0.5% of CPU time is spent on kernel space. ni (niceness): the ratio of CPU time spent on low priority processes. i...

Use time command. time ./perl-timeout-example 100.100.100 We could not ping the desired address! real 0m5.0013s user 0m0.004s sys 0m0.008s Real: Total time from start to finish of the call, including the CPU time spent on other processes. User: The amount of CPU time spent i...

Often you want to lock the entire object while you perform multiple operations on it. For example, if you need to examine or modify the object using iterators. Whenever you need to call multiple member functions it is generally more efficient to lock the whole object rather than individual member fu...

We can create dynamic component and get the instances of component into an array and finally rendered it on template. For example, we can can consider two widget component, ChartWidget and PatientWidget which extended the class WidgetComponent that I wanted to add in the container. ChartWidget.ts ...

Here we are having a list of todo items that is passed to the props of our component. Each todo item has a text and id property. Imagine that the id property comes from a backend datastore and is a unique numeric value: todos = [ { id: 1, text: 'value 1' }, { id: 2, te...

This is especially useful if we have a class that we want to extend in the rule. See example below for a more convenient method. import org.junit.rules.TestRule; import org.junit.runners.model.Statement; public class AwesomeTestRule implements TextRule { @Override public Stateme...

JUnit has an abstract implementation of @TestRule that lets you write a rule in a more simpler way. This is called ExternalResource and provides two protected methods that can be extended like this: public class AwesomeTestRule extends ExternalResource { @Override protected void befor...

Add the hyperloop gem to your rails (4.0 - 5.1) Gemfile bundle install Add the hyperloop manifest to the application.js file: // app/assets/javascripts/application.js ... //= hyperloop-loader Create your react components, and place them in the hyperloop/components directory # app/hyperl...

class Hello < Hyperloop::Component # params (= react props) are declared using the param macro param :guest render do "Hello there #{params.guest}" end end # to "mount" Hello with guest = "Matz" say Hello(guest: 'Matz') # params can be giv...

# Event handlers are attached using the 'on' method class ClickMe < Hyperloop::Component render do DIV do SPAN { "Hello There" } A { "Click Me" }.on(:click) { alert('you did it!' } end end end

In certain cases (e.g. logging) it might be useful to run task and do not await for the result. The following extension allows to run task and continue execution of the rest code: public static class TaskExtensions { public static async void RunAndForget( this Task task, Action<E...

When designing a linked list, you can avoid all the special-cases (empty list, first node, last node, etc) by using a sentry node. Let's see how that is done: struct Node { Node* next; Node* prev; T data; }; // helper function to link 2 nodes void Link(Node* n1, Node* n2) { ...

Let's say we want to console.log each time the component mounts: hocLogger.js export default function hocLogger(Component) { return class extends React.Component { componentDidMount() { console.log('Hey, we are mounted!'); } render() { return <Component {...this....

Let's say we have a component that should only be displayed if the user is logged in. So we create a HOC that checks for the authentication on each render(): AuthenticatedComponent.js import React from "react"; export function requireAuthentication(Component) { return class Auth...