package idv.design.pattern.singleton.lazy;
/**
* @author Carl Lu
*/
public class Singleton {
/*
* This is also called "optimistic lock singleton".
*/
/*
* Define a variable for saving instance that will be build.
*/
private static Singleton uniqueInstance = null;
/*
* The constructor should be private so that we can control the instance number.
*/
private Singleton() {
}
/*
* Need to define a method for providing class instance to clients.
* To ensure thread-safe, please add keyword synchronized in the method declaration.
*
* @return Singleton singleton instance
*/
public static synchronized Singleton getInstance() {
if (uniqueInstance == null) {
uniqueInstance = new Singleton();
}
return uniqueInstance;
}
public void singletonOperation() {
System.out.println("Do something here...");
}
}