source code
/* The Computer Language Benchmarks Game
http://benchmarksgame.alioth.debian.org/
contributed by Michael Barker
based on a contribution by Luzius Meisser
*/
/**
* This implementation uses standard Java threading (native threads).
*
* This implementation simply adds the new functionality to the orginal
* implementation by Luzius Meisser from old chameneos shootout. The interesting
* part of this implementation, is that while a creature is waiting it does not
* block its thread, rather it spins in a loop using a Thread.yield().
*/
public class chameneosredux {
enum Colour {
blue,
red,
yellow
}
private static Colour doCompliment(Colour c1, Colour c2) {
switch (c1) {
case blue:
switch (c2) {
case blue:
return Colour.blue;
case red:
return Colour.yellow;
case yellow:
return Colour.red;
}
case red:
switch (c2) {
case blue:
return Colour.yellow;
case red:
return Colour.red;
case yellow:
return Colour.blue;
}
case yellow:
switch (c2) {
case blue:
return Colour.red;
case red:
return Colour.blue;
case yellow:
return Colour.yellow;
}
}
throw new RuntimeException("Error");
}
static class MeetingPlace {
private int meetingsLeft;
public MeetingPlace(int meetings) {
this.meetingsLeft = meetings;
}
private Colour firstColour = null;
private int firstId = 0;
Future<Pair> current;
public Pair meet(int id, Colour c) throws Exception {
Future<Pair> newPair;
synchronized (this) {
if (meetingsLeft == 0) {
throw new Exception("Finished");
} else {
if (firstColour == null) {
firstColour = c;
firstId = id;
current = new Future<Pair>();
} else {
Colour newColour = doCompliment(c, firstColour);
current.setItem(new Pair(id == firstId, newColour));
firstColour = null;
meetingsLeft--;
}
newPair = current;
}
}
return newPair.getItem();
}
}
public static class Future<T> {
private volatile T t;
public T getItem() {
while (t == null) {
Thread.yield();
}
return t;
}
// no synchronization necessary as assignment is atomic
public void setItem(T t) {
this.t = t;
}
}
static class Creature implements Runnable {
private final MeetingPlace place;
private int count = 0;
private int sameCount = 0;
private Colour colour;
private int id;
public Creature(MeetingPlace place, Colour colour) {
this.place = place;
this.id = System.identityHashCode(this);
this.colour = colour;
}
public void run() {
try {
while (true) {
Pair p = place.meet(id, colour);
colour = p.colour;
if (p.sameId) {
sameCount++;
}
count++;
}
} catch (Exception e) {}
}
public int getCount() {
return count;
}
public String toString() {
return String.valueOf(count) + getNumber(sameCount);
}
}
private static void run(int n, Colour...colours) {
MeetingPlace place = new MeetingPlace(n);
Creature[] creatures = new Creature[colours.length];
for (int i = 0; i < colours.length; i++) {
System.out.print(" " + colours[i]);
creatures[i] = new Creature(place, colours[i]);
}
System.out.println();
Thread[] ts = new Thread[colours.length];
for (int i = 0; i < colours.length; i++) {
ts[i] = new Thread(creatures[i]);
ts[i].start();
}
for (Thread t : ts) {
try {
t.join();
} catch (InterruptedException e) {
}
}
int total = 0;
for (Creature creature : creatures) {
System.out.println(creature);
total += creature.getCount();
}
System.out.println(getNumber(total));
System.out.println();
}
public static void main(String[] args) {
int n = 600;
try {
n = Integer.parseInt(args[0]);
} catch (Exception e) {
}
printColours();
System.out.println();
run(n, Colour.blue, Colour.red, Colour.yellow);
run(n, Colour.blue, Colour.red, Colour.yellow, Colour.red, Colour.yellow,
Colour.blue, Colour.red, Colour.yellow, Colour.red, Colour.blue);
}
public static class Pair {
public final boolean sameId;
public final Colour colour;
public Pair(boolean sameId, Colour c) {
this.sameId = sameId;
this.colour = c;
}
}
private static final String[] NUMBERS = {
"zero", "one", "two", "three", "four", "five",
"six", "seven", "eight", "nine"
};
private static String getNumber(int n) {
StringBuilder sb = new StringBuilder();
String nStr = String.valueOf(n);
for (int i = 0; i < nStr.length(); i++) {
sb.append(" ");
sb.append(NUMBERS[Character.getNumericValue(nStr.charAt(i))]);
}
return sb.toString();
}
private static void printColours() {
printColours(Colour.blue, Colour.blue);
printColours(Colour.blue, Colour.red);
printColours(Colour.blue, Colour.yellow);
printColours(Colour.red, Colour.blue);
printColours(Colour.red, Colour.red);
printColours(Colour.red, Colour.yellow);
printColours(Colour.yellow, Colour.blue);
printColours(Colour.yellow, Colour.red);
printColours(Colour.yellow, Colour.yellow);
}
private static void printColours(Colour c1, Colour c2) {
System.out.println(c1 + " + " + c2 + " -> " + doCompliment(c1, c2));
}
}