AtomiciProizPotr

package djolepokusavaatomike;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import os.simulation.Application;
import os.simulation.AutoCreate;
import os.simulation.Color;
import os.simulation.Container;
import os.simulation.Item;
import os.simulation.Operation;
import os.simulation.Thread;

/*
 * Dat je bafer fiksne velicine. Vise procesa zeli da istovremeno dodaje i
 * uklanja elemente sa ovog bafera.
 *
 * Realizovati operaciju dodavanja tako da, ako je bafer pun, blokira proces
 * dok se ne oslobodi mesto za novi element. Takodje, realizovati operaciju
 * uklanjanja tako da, ako je bafer prazam, blokira proces dok se ne doda novi
 * element.
 */
public class BaferAtomici extends Application{


    protected Bafer bafer = new Bafer(12);
    protected class Bafer {

        private AtomicInteger brEle = new AtomicInteger(0);
        private AtomicInteger brMesta = new AtomicInteger(12); // vidi
        private AtomicBoolean ko = new AtomicBoolean(true);


        private final List<Element> lista = new ArrayList<>();
        private final int velicina;

        public Bafer(int velicina) {
            this.velicina = velicina;
        }
        // Sinhronizacija
        public void stavi(Element o) {

            boolean ok;
            do {
                int oldValue = brMesta.get();
                int newValue = oldValue - 1;
                ok = newValue >= 0 ;
                if(ok) {
                    ok = brMesta.compareAndSet(oldValue, newValue);
                }
            }while(!ok);

            while(!ko.compareAndSet(true, false)) {}
            try {

                lista.add(o);
                elementi.addItem(o);
            }finally {
                ko.set(true);
            }
            brEle.incrementAndGet();
        }

        // Sinhronizacija
        public Element uzmi() {

            boolean ok;
            do {
                int oldValue = brEle.get();
                int newValue = oldValue - 1 ;
                ok = newValue >=0 ;
                if(ok) {
                    ok = brEle.compareAndSet(oldValue, newValue);
                }
            }while(!ok);

            while(!ko.compareAndSet(true, false)) {}
            Element result;
            try {

                result = lista.remove(0);
                elementi.removeItem(result);
                brMesta.incrementAndGet();
                return result;

            }finally {
                ko.set(true);

        }
            }
    }

    // ------------------- //
    //    Sistemski deo    //
    // ------------------- //
    // Ne dirati kod ispod //
    // ------------------- //

    @AutoCreate(4)
    protected class Proizvodjac extends Thread {

        private final int id = getID();
        private int br = 0;

        @Override
        protected void step() {
            Element element = proizvedi(id + "x" + (br++));
            bafer.stavi(element);
        }

    }

    @AutoCreate(4)
    protected class Potrosac extends Thread {

        @Override
        protected void step() {
            Element element = bafer.uzmi();
            potrosi(element);
        }
    }

    protected final Container proizvodjaci = box("Произвођачи").color(NAVY);
    protected final Container potrosaci    = box("Потрошачи").color(MAROON);
    protected final Container elementi     = box("Елементи").color(NEUTRAL_GRAY);
    protected final Container main         = row(proizvodjaci, elementi, potrosaci);
    protected final Operation proizvodjac  = init().name("Произв. %d").color(AZURE).text("Чека").container(proizvodjaci);
    protected final Operation potrosac     = init().name("Потр. %d").color(ROSE).text("Чека").container(potrosaci);
    protected final Operation element      = init();
    protected final Operation proizvodnja  = duration("3±1").text("Производи").textAfter("Чека");
    protected final Operation potrosnja    = duration("7±2").text("Троши %s").textAfter("Чека");

    protected Element proizvedi(String vrednost) {
        proizvodnja.performUninterruptibly();
        return new Element(vrednost);
    }

    protected void potrosi(Element element) {
        potrosnja.performUninterruptibly(element.getName());
    }

    protected class Element extends Item {

        public Element(String vrednost) {
            setName(vrednost);
        }

        private int getIndex() {
            return bafer.lista.indexOf(this);
        }

        @Override
        public Color getColor() {
            int index = getIndex();
            if ((index >= 0) && (index < bafer.velicina)) {
                return CHARTREUSE;
            } else {
                return ORANGE;
            }
        }

        @Override
        public String getText() {
            return String.format("Bafer[%d]", getIndex());
        }
    }

    public static void main(String[] arguments) {
        launch("Произвођачи и потрошачи");
    }

}