public class ThreadIDMain extends Object implements Runnable {
private ThreadID var;
public ThreadIDMain(ThreadID var) {
this.var = var;
}
public void run() {
try {
print("var.getThreadID()=" + var.getThreadID());
Thread.sleep(2000);
print("var.getThreadID()=" + var.getThreadID());
} catch (InterruptedException x) {
}
}
private static void print(String msg) {
String name = Thread.currentThread().getName();
System.out.println(name + ": " + msg);
}
public static void main(String[] args) {
ThreadID tid = new ThreadID();
ThreadIDMain shared = new ThreadIDMain(tid);
try {
Thread threadA = new Thread(shared, "threadA");
threadA.start();
Thread.sleep(500);
Thread threadB = new Thread(shared, "threadB");
threadB.start();
Thread.sleep(500);
Thread threadC = new Thread(shared, "threadC");
threadC.start();
} catch (InterruptedException x) {
}
}
}
class ThreadID extends ThreadLocal {
private int nextID;
public ThreadID() {
nextID = 10001;
}
private synchronized Integer getNewID() {
Integer id = new Integer(nextID);
nextID++;
return id;
}
// override ThreadLocal's version
protected Object initialValue() {
print("in initialValue()");
return getNewID();
}
public int getThreadID() {
Integer id = (Integer) get();
return id.intValue();
}
private static void print(String msg) {
String name = Thread.currentThread().getName();
System.out.println(name + ": " + msg);
}
}