ruby singleton

Ensure that a class has only one instance and provides a global access point to it. The code is as follows: /** * Singleton mode * * Ensure that a class has only one instance and provides a global access point to it. * */ Class Singleton { Static private $ _ instance = null; Private function _ construct () { } Static public function getInstance () { If (is_null (self ::$ _ instance ))

Ensure that a class has only one instance and provides a global access point to it. Copy codeThe code is as follows: /** * Singleton mode * * Ensure that a class has only one instance and provides a global access point to it. * */ Class Singleton { Static private $ _ instance = null; Private function _ construct () { } Static public function getInstance () { If (is_null (self ::$ _ ins

Ensure that a class has only one instance and provides a global access point to it. The code is as follows: /*** Singleton mode** Ensure that a class has only one instance and provides a global access point to it.**/Class Singleton{Static private $ _ instance = null;Private function _ construct (){}Static public function getInstance (){If (is_null (self ::$ _ instance )){Self: $ _ instance = new

What is a single case, and what is its role? The singleton pattern is understood from the name. Single is once. The example is to instantiate an object, that is, I don't care how many times I use it to instantiate an object. OK, what is the function of this design pattern? The singleton mode can ensure that there is only one instance of a class in the system, and the instance is easy to be accessed by th

CopyCodeThe Code is as follows: /** * Singleton Mode * * Ensure that a class has only one instance and provides a global access point to it. * */ Class Singleton { Static private $ _ instance = NULL; Private function _ construct (){} Static public function getinstance (){If (is_null (Self ::$ _ instance )){SELF: $ _ instance = new Singleton ();}Return

The Singleton mode is met by two points: 1. One class can only have one unique instance. 2. Global access points are provided. Implementation1 Public class Singleton { This is a simple implementation method with thread security issues. For example, when thread T1 runs to (B), it suddenly sleeps. Then thread T2 runs from (a), thread T1 is still in (B) sleep, and no instance is created, in this case,

Array usage in Ruby, ruby array usage Ruby arrays are ordered. What about any object ?? The set of integer indexes. The elements in each array are associated and an index is mentioned. Array subscript starts from 0, such as C or Java. Negative index assumes that the end of the array --- that is,-1 indicates the array index of the last element,-2 is the next eleme

Some basic operations on Ruby processing time, And ruby processing basic operations Get the current date and time: The following is a simple example to get the current date and time: #!/usr/bin/ruby -wtime1 = Time.newputs "Current Time : " + time1.inspect# Time.now is a synonym:time2 = Time.nowputs "Current Time : " + time2.inspect This produces the following res

is not a professional web crawler crawling, just before a very bad site to help people brush the ticket started to learn the web crawler tools.The initial time is to use the Python urllib2, get the page when the text processing, later in the forum to see the Beautifulsoap this level of artifact, Python processing this is really convenient, but later I met the Ruby and rails, from the faithless, Even read the metaprogramming

Some basic knowledge about modules in Ruby and basic knowledge about Ruby modules A module is similar to a class. It can also be called a class that cannot be instantiated ". Because the Class is a subclass of the Module Class, it may be better to say "Class = Module + instantiation Capability. What is the so-called module used? There are two main types of functions: Mix-in and namespace. Mix-in is actually

Do you know all the 25 php design patterns? The following code describes the singleton mode )? Php * Singleton mode ensures I... 25 php typesDesign ModeDo you all know? The following code is used to introduceSingleton mode) Display (); $ obj1 = Singleton: getInstance (); var_dump ($ obj = $ obj1 )); Other related design patterns: Other related design patterns

/*main.cpp*/#include "Singleton.h" int main () {Singleton *sgn=singleton::instance (); return 0;}Singleton pattern (singleton mode)

We need a singleton in programming, but not just a Singleton, but more That is, Class A isController, Class B isInstance panel For the convenience of finding Class A, use a single example, To make it easy to find Class B, Class A uses a singleton in a single example. Singe case a-Singe case B- Do not use new A. getinstance (). B. Call Method

This section describes the regular expressions and Ruby Regular Expressions in ruby. A regular expression is a character of a special sequence. It matches or searches for other strings or string sets by using a pattern with special syntax.Syntax A regular expression is literally a pattern between a slash or any separator following % r, as shown below: /Pattern // pattern/im # You can specify the option % r!

Interpreting the usage of annotations in Ruby and interpreting ruby annotations The Code Annotated In the Ruby line is ignored at runtime. Single line comment # starts with the characters. They start from # To the end of the line as follows: #! /Usr/bin/ruby-w # This is a single line comment. puts "Hello,

A simple tutorial on JSON Processing Using Ruby, and a json tutorial on ruby Processing Environment Configuration Before using Ruby to encode or decode JSON data, we need to install the Ruby JSON module. Before installing this module, you must first install Ruby gem. We will

Recommended syntax style in Ruby programming, and ruby programming syntax Style Use: Reference constants (including classes and modules) and constructors (such as Array () or Nokogiri: HTML ()).Never use: to call methods. # bad SomeClass::some_method some_object::some_method # good SomeClass.some_method some_object.some_method SomeModule::SomeClass::SOME_CONST SomeModule::SomeClass() Enclose def pa

Ruby is a powerful object-oriented scripting language that allows you to easily and quickly perform object-oriented programming. sometimes using formal object-oriented languages such as Smalltalk, Eiffel, and C ++ to develop small projects seems a little complicated. Ruby can meet these object-oriented programming needs. of course, you can also use Ruby for gener

(/(.) (.) /) {$1.upcase + $} End def upcase! gsub! (/(.) (.) /) {$1.upcase + $} End End Puts B.upcase # GoOdBye Puts B # goodbye b.upcase! Puts B # GoOdBye This class is called Singleton class, because this class is for the object of B. and design pattern Singleton object is similar, only occurs once of Dongdong we call Singleton.

Singleton mode is a common design pattern. In Java applications, singleton objects guarantee that only one instance of the object exists in a JVM. There are several benefits to this model:1, some classes are created more frequently, for some large objects, this is a large amount of system overhead;2, eliminate the new operator, reduce the use of system memory frequency, reduce the GC pressure;3, some classe