where singleton pattern is used in java code example
Example 1: java singleton
- A private constructor
- A static field containing its only instance
- A static factory method for obtaining the instance
public final class ClassSingleton
{
private static ClassSingleton INSTANCE;
private String info = "Initial info class";
private ClassSingleton()
{
}
public static ClassSingleton getInstance()
{
if(INSTANCE == null)
{
INSTANCE = new ClassSingleton();
}
return INSTANCE;
}
}
=============Usage============
To use our ClassSingleton, we simply need to get the instance statically:
ClassSingleton classSingleton1 = ClassSingleton.getInstance();
System.out.println(classSingleton1.getInfo());
ClassSingleton classSingleton2 = ClassSingleton.getInstance();
classSingleton2.setInfo("New class info");
System.out.println(classSingleton1.getInfo());
System.out.println(classSingleton2.getInfo());
Example 2: singleton pattern
class Singleton:
__instance = None
def __new__(cls, *args):
if cls.__instance is None:
cls.__instance = object.__new__(cls, *args)
return cls.__instance