ruby singleton

Singleton mode: There is only one instance of an object in the context.Application scenario: thread pool, cache, etc. a system requires only one scene.Three common single-case modes:1. Lazy Loadingpublicclass Singleton { privatestatic Singleton uniqueInstance; privateSingleton() {} publicstaticgetInstance() { ifnull) new

Analysis: 1. singleton mode indicates that only one instance of the class is created. First, set the class constructor to private, and then write a public static function to create the instance, you can use a static pointer of this class to save a unique instance. Before creating the instance, you must determine whether the instance exists. If the instance has already been created, it will not be created. 2. You can lock static functions for thread sa

Overview: The Singleton mode is called the singleton mode or Singleton mode. It ensures that a class has only one instance throughout the project. You can easily use the required class methods in multiple different classes. Application: It is often used in game programming and multi-thread programming to read configuration files and write logs. Principle: Its con

Singleton single-State Design Mode singleton 1. Concept 1. In Java applications, only one instance of a Class can exist. 2. One instance 1) private constructor2) Private Static instances3) Public and static access 1) prevent creating new instances2) Prevent Modification3) must be able to obtain Public class Singleton {// 1. private

What is a singleton mode: (singleton)The singleton mode is intended to be the only instance of the class, providing an access point for sharing resources with the customer class.Singleton class, you must provide an access point (a special class method)//SingletonTools.h//single-instance mode implementation////Created by Cloudwalk on 15/9/11.//Copyright (c) 2015 C

For an example of a singleton pattern in PHP design mode, the principles and Techniques of PHP singleton mode are used to learn the implementation of PHP singleton mode. Singleton mode (Duty mode): An object (before learning the design pattern, the need to understand the object-oriented thinking) is only resp

Copy CodeThe code is as follows: /** * Single case mode * * Ensure that a class has only one instance and provides a global access point to access it * */ Class Singleton { static private $_instance = NULL; Private Function __construct () { } static public Function getinstance () { if (Is_null (self::$_instance)) { Self::$_instance = new Singleton (); } return self::$_instance; } Public Function display

Each app has and has only one uiapplication, similar to UIApplication " [uiapplication sharedapplication]" This one class has and only unique instances of the design-singleton pattern.single case design and key pointsA singleton class is designed as shown inThere are a few points to note:(1) The instance needs to be static to prevent it from being modified in other files;(2) In view of the development habit

Tutorial on the basic usage of Regular Expressions in Ruby programs, ruby Regular Expressions Most of Ruby's built-in types are similar to other programming languages. Mainly include strings, integers, floats, and arrays. However, only script languages such as Ruby, Perl, and awk provide support for built-in expression types. Although the regular expression is re

Explain in detail the condition judgment statements in Ruby and explain the ruby judgment statements Ruby provides conditional structures, which are common in modern programming languages. Here, we will explain all the Ruby conditional statements and modifiers.Ruby if... else statement:Syntax: if conditional [then] co

Introduction to Ruby operators and statement priority, ruby operator priority Ruby is a language with strong expressive power. It is proud of its rich operators and syntactic sugar. Although Ruby has always regarded the principle of least surprise as one of its philosophies, but it is often surprising that it is diffic

Object array sorting in Ruby and Ruby object array sorting Sorting of Ruby object arrays The author has just come into contact with Ruby, because he previously thought that the script language syntax is not standardized and he is somewhat biased against the script language. For example, he does not need to learn PYTHON

Copy the code code as follows: /** * Single case mode * * Ensure that a class has only one instance and provides a global access point to access it * */ Class Singleton { static private $_instance = NULL; Private Function __construct () { } static public Function getinstance () { if (Is_null (self::$_instance)) { Self::$_instance = new Singleton (); } return self::$_instance; } Public Function display

Implement Singleton (Singleton) Mode The Singleton mode is often used to control application-level shared resources. It should be said that this mode is frequently used. Now let's look at the implementation methods in objective-C.To implement a singleton class, at least four steps are required:1. Implement a static ins

Java Singleton Pattern Singleton Mode Wikipedia: When you click open link to apply this mode, the class of the singleton object must ensure that only one instance exists. Key points: 1. private constructor-other classes cannot instantiate a new object.2. Private reference-External modification is not allowed.3. The public static method is the only way to obtain o

Ruby string and array maximization problems, ruby Problems Max Method b=[1,3,55,777,2,4,6,8,0] For numeric data, max obtains the maximum value of the array, and min obtains the minimum value of the array. b.max => 777b.min => 0 It has no practical significance for comparing the size of string arrays,The example in ruby is # enum.max -> obj# enum.max { |a,

Detailed description of matching and replacement operations on strings by regular expressions in Ruby, and ruby Regular Expressions Regular Expression matching Speaking of Ruby, of course, we need to mention its regular expression mechanism. As a powerful matching language, regular expressions are increasingly used in different fields, from string verification, m

Three methods for executing periodic tasks (scheduled tasks) IN ruby: ruby periodic 1. Preface Whether using ruby for system management or using rails for web development, periodic tasks may occur. They are scheduled to take a certain period of time (1 hour, 2 days ......) continuously triggered. In ruby, I think it is

Ruby vs Python advantages and disadvantages, ruby vs python Ruby and Python are too similar, and most of the trade-offs are personal preferences. For example, I think Python's "There is only one way to do it. "than Ruby's" There are always ways to do it. "Well, it's not just about team collaboration. More importantly, you can quickly understand what code you wrot

Ruby 7-day entry (2 functions, arrays and classes), ruby 7-dayDAY 2 Continue the next day. Today we will focus on the basic elements of functions, collections, classes, and other programming.2.1 simple definition of function 2.1.1 def tell_me puts true end Defining a simple function (No parameter and no return value) is simple. Use def end to wrap the function body. 2.1.2 Parameters def tell_me(a)puts ae