Tutorial by Examples: er

@BodyParser.Of(BodyParser.Json.class) public Result sayHello() { JsonNode json = request().body().asJson(); String name = json.findPath("name").textValue(); if(name == null) { return badRequest("Missing parameter [name]"); } else { return ok...

<!-- <moduleDir>/etc/<area>/di.xml --> <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd"> <!-- ... --> <preference for="Vendor\Name...

After the user signed in to Facebook at your app, now it's time to fetch the data you requested at the FBButton.readPermissions. Swift: enum FacebookParametesField : String { case FIELDS_KEY = "fields" case FIELDS_VALUE = "id, email, picture, first_name, last_name" ...

Escape sequences are not restricted to string and char literals. Suppose you need to override a third-party method: protected abstract IEnumerable<Texte> ObtenirŒuvres(); and suppose the character Œ is not available in the character encoding you use for your C# source files. You are lucky...

There are many cases when one has created an NSDate from only an hour and minute format, i.e: 08:12 that returns from a server as a String and you initiate an NSDate instance by these values only. The downside for this situation is that your NSDate is almost completely "naked" and what yo...

A self reference can be useful to build a hierarchical tree. This can be achieved with add_reference in a migration. class AddParentPages < ActiveRecord::Migration[5.0] def change add_reference :pages, :pages end end The foreign key column will be pages_id. If you want to decide a...

As discussed in the introduction, the gradle wrapper functionality works because a jar is downloaded into the project to be used when the gradlew command is run. However this may not get committed and after the next time the project is checked out, gradlew will fail to run with the error: Error: C...

Gradle has the ability to add a wrapper to projects. This wrapper alleviates the need for all users or continuous integration systems to have Gradle installed. It also prevents version issues where there is some incompatibility between the version the project uses and that which users have installed...

Create SharedPreferences BuyyaPref SharedPreferences pref = getApplicationContext().getSharedPreferences("BuyyaPref", MODE_PRIVATE); Editor editor = pref.edit(); Storing data as KEY/VALUE pair editor.putBoolean("key_name1", true); // Saving boolean - true/false ...

Let's say you have class with generic methods. And you need to call its functions with reflection. public class Sample { public void GenericMethod<T>() { // ... } public static void StaticMethod<T>() { //... } } Let's say we want to...

From Apple documentation: Use the CTCallCenter class to obtain a list of current cellular calls, and to respond to state changes for calls such as from a dialing state to a connected state. Such state changes are known as cellular call events. The purpose of CTCallCenter is to give the develop...

Write to a file test.txt: String filepath ="C:\\test.txt"; FileOutputStream fos = null; try { fos = new FileOutputStream(filepath); byte[] buffer = "This will be written in test.txt".getBytes(); fos.write(buffer, 0, buffer.length); fos.close(); } c...

By default class annotations do not apply to types extending them. This can be changed by adding the @Inherited annotation to the annotation definition Example Consider the following 2 Annotations: @Inherited @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) public @interface Inher...

public static void Main(string[] args) { var studentList = new List<Student>(); studentList.Add(new Student("Scott", "Nuke")); studentList.Add(new Student("Vincent", "King")); studentList.Add(new Student("Craig", "Be...

If you want the Value Types vs Reference Types in methods example to work properly, use the ref keyword in your method signature for the parameter you want to pass by reference, as well as when you call the method. public static void Main(string[] args) { ... DoubleNumber(ref number); ...

Self-referential association is used to associate a model with itself. The most frequent example would be, to manage association between a friend and his follower. ex. rails g model friendship user_id:references friend_id:integer now you can associate models like; class User < ActiveRecord:...

// A fixed size raw array matrix (that is, a 2D raw array). #include <iostream> #include <iomanip> using namespace std; auto main() -> int { int const n_rows = 3; int const n_cols = 7; int const m[n_rows][n_cols] = // A raw array matrix. ...

This is useful to see if there are any non-printable characters, or non-ASCII characters. e.g. If you have copy-pasted the code from web, you may have quotes like ” instead of standard ". $ cat -v file.txt $ cat -vE file.txt # Useful in detecting trailing spaces. e.g. $ echo '” ' | c...

Because in .NET 3.5 and older you don't have Lazy<T> class you use the following pattern: public class Singleton { private Singleton() // prevents public instantiation { } public static Singleton Instance { get { return Nested.instanc...

Once the number of abilities definitions start to grow in number, it becomes more and more difficult to handle the Ability file. The first strategy to handle these issue is to move abilities into meaningful methods, as per this example: class Ability include CanCan::Ability def initialize(...