Chciałbym wykonać symulator dostępu do medium transmisyjnego. W skrócie dostęp do medium ma wiele osób, ale tylko jedna osoba może w jednym czasie coś wysyłać. Medium ma swoje opóźnienie. Gdy dwie osoby zaczną wysyłać jakieś dane muszą wysłać je ponownie.
Program tworze na wątkach... W tym mam problem nie wiem jak je zsynchronizować...
package zad2;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
public class Cable {
private long wait;
private PrintWriter out;
private boolean open = true;
private boolean colizion = false;
private int users = 0;
public Cable(long wait, String output) throws FileNotFoundException{
this.wait=wait;
out = new PrintWriter(new File(output));
}
synchronized public void write(String s){
out.println(s);
out.flush();
}
public boolean isOpen(){
return open;
}
synchronized public void addUser(){
if(++users>0)
open=false;
if(users>1)
colizion = true;
}
synchronized public void degUser(){
if(--users==0){
colizion = false;
open = true;
}
}
public boolean startMessage(int who, long what) throws InterruptedException{
write(who + " start send ");
Thread.sleep(wait);
if(continueMessage(who,what)){
Thread.sleep(wait);
return endMessage(who);
}
else
return false;
}
public synchronized boolean continueMessage(int who, long what){
addUser();
if(!colizion){
write(who + " send "+ what +" "+ users);
return true;
}else{
degUser();
write(who + " error send");
return false;
}
}
public synchronized boolean endMessage(int who) throws InterruptedException{
if(!colizion){
write(who + " END send !!!!");
degUser();
return true;
}
write(who + " error send");
degUser();
return false;
}
}
package zad2;
import java.util.Random;
public class Host extends Thread {
private int number;
private Cable cable;
private int ratio=1;
private long wait;
private long mess;
private Random gen = new Random();
public Host(Cable cable, int number, long wait){
this.cable = cable;
this.number = number;
this.wait=wait;
mess = gen.nextLong();
}
public void run(){
while(true){
while(!cable.isOpen()){
long w = Math.abs((long) (gen.nextLong() % (wait*ratio)));
try {
sleep(w);
} catch (InterruptedException e) {}
}
try {
if(cable.startMessage(number, mess)){
break;
}
} catch (InterruptedException e) {}
ratio +=1;
}
}
}
package zad2;
import java.io.FileNotFoundException;
public class Zadanie2 {
private static long waitCable = 10;
private static long waitHosts = 200;
private static String out = "Zad2.txt";
private static int nHost = 100;
public static void main(String argv[]) throws FileNotFoundException{
Cable cable = new Cable(waitCable,out);
Host hosts[] = new Host[nHost];
for(int i=0; i<nHost; ++i){
hosts[i]=new Host(cable, i, waitHosts);
hosts[i].start();
}
}
}
Java