Java Single Example Class Demo__java

It is not recommended to use Singleton1 and Singleton2,singleton3 basic to meet the requirements, SINGLETON5 support delay loading, but the implementation of a bit of trouble, effective Java authors recommend the enumeration to implement a single case, automatic support serialization mechanism , preventing deserialization from recreating new objects, and absolutely preventing multiple instantiations
implementing a single example by enumerating

Package Com.basic.designpatterns.create.singleton;

/** *
 Single Case
 * *
 @author chichuduxing
 * @date February 4, 2017 pm 4:40:22

/class Resource {
	//specific business. c10/>public void DoSomething () {
		System.out.println ("working");
	}

/**
 * Supports thread security by enumerating the class implementations (the constructs must be private in the enumeration class), supporting serialization */public
enum Enumsingleton {

	INSTANCE;

	Private Resource instance = null;

	Private Enumsingleton () {
		instance = new Resource ();
	}

	Public Resource getinstance () {return
		instance;
	}
}

Single case class that implements a single example by enumerating, but does not expose details

Package Com.basic.designpatterns.create.singleton;

/**
 * @author chichuduxing
 * @date April 3, 2017 pm 7:54:42/public

class Enumfactory {

	/**
	 * A method of obtaining a single case from abroad
	 *
	 * @return Single
	 object
	/public static Singresource getinstance () {
		return EnumSingleton.INSTANCE.getInstance ();
	}

	/**
	 * Supports thread security by enumerating class implementations (constructs must be private in the enumeration class), supporting serialization/
	private enum Enumsingleton {

		INSTANCE;

		Private Singresource instance = null;

		Private Enumsingleton () {
			instance = new Singresource ();
		}

		Public Singresource getinstance () {return
			instance;
		}
	}

	/**
	 * Test Method
	 *
	 * @param args
	/public static void main (string[] args) {
		Enumfactory.getinstance (). dosomething ();
	}

/**
 * Specific implementation of the function of the single example class
/class Singresource {public
	Singresource () {

	}

	//specific business.
	public void DoSomething () {
		System.out.println ("working");
	}

several other ways of implementing

Package Com.basic.designpatterns.create.singleton; /** * Single Case Mode * * @author chichuduxing * @date February 4, 2017 11:19:02//** * lazy, thread unsafe * * Class Singleton1 {privat

	e Singleton1 () {} private static Singleton1 instance = NULL;
		public static Singleton1 getinstance () {if (null = = instance) {return new Singleton1 ();
	return instance; 

	}/** * lazy, thread-safe Efficiency low * * Class Singleton2 {private Singleton2 () {} private static Singleton2 instance = NULL;
		public static synchronized Singleton2 getinstance () {if (null = = instance) {return new Singleton2 ();
	return instance;
 }/** * A hungry man, thread-safe when a single classloader is not locked, threads are safe, but the class is loaded with a new object.

	* * Class Singleton3 {private Singleton3 () {} private static Singleton3 instance = new Singleton3 ();
	public static Singleton3 getinstance () {return instance; }/** * Double lock check lazy, thread safe. Need to add volatile keyword </br> * Because instance = new Singleton4 (); not atomic Operation,</br> * If the processor is reordered, you can Can instance in the morning although not NULL, but the instance has notInitialization </br>/* class Singleton4 {private Singleton4 () {}//required add volatile keyword private volatile static Singleton4

	instance = null; public static Singleton4 getinstance () {if (instance = null) {synchronized (Singleton4.class) {if (null = = in
				Stance) {instance = new Singleton4 ();
	}} return instance; }/** * Internal class, the internal class is deferred loading, will only be loaded on the first use, do not load without using.
 Lazy, thread-safe. * * Class Singleton5 {private Singleton5 () {} static class Innersingleton {private static final Singleton5 Instan
	CE = new Singleton5 ();
	public static final Singleton5 getinstance () {return innersingleton.instance;
		} public class Singletonpatterndemo {//Recommended Enumsingleton//second SINGLETON5 public static void Main (string[) args) {
	EnumSingleton.INSTANCE.getInstance (). dosomething ();
 }
}