singleton pattern
1. Concept
Hungry mode, lazy mode
2. Examples
package com.study.current.thread.day02;
/**
* Singleton, multi-threaded
*/
public class InnerSingleton {
private static class Singletion{
private static Singletion single = new Singletion();
}
public static Singletion getInstance(){
return Singletion.single;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
package com.study.current.thread.day02;
import java.util.DuplicateFormatFlagsException;
public class DoubleCheckDemo {
private static DoubleCheckDemo dc ;
public static DoubleCheckDemo getDc(){
if(dc == null){
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace ();
}
synchronized (DoubleCheckDemo.class) {
if(dc == null){
dc = new DoubleCheckDemo();
}
}
}
return dc ;
}
/**
* @param args
*/
public static void main(String[] args) {
Thread t1 = new Thread(new Runnable() {
public void run() {
System.out.println(DoubleCheckDemo.getDc().hashCode());
}
});
Thread t2 = new Thread(new Runnable() {
public void run() {
System.out.println(DoubleCheckDemo.getDc().hashCode());
}
});
t1.start();
t2.start();
}
}