package concurrency;//: concurrency/ToastOMatic.java
// A toaster that uses queues.
import java.util.concurrent.*;
import java.util.*;
import static net.mindview.utill.Print.*;class Toast {public enum Status { DRY, BUTTERED, JAMMED }private Status status = Status.DRY;private final int id;public Toast(int idn) { id = idn; }public void butter() { status = Status.BUTTERED; }public void jam() { status = Status.JAMMED; }public Status getStatus() { return status; }public int getId() { return id; }public String toString() {return "Toast " + id + ": " + status;}
}class ToastQueue extends LinkedBlockingQueue<Toast> {}class Toaster implements Runnable {private ToastQueue toastQueue;private int count = 0;private Random rand = new Random(47);public Toaster(ToastQueue tq) { toastQueue = tq; }public void run() {try {while(!Thread.interrupted()) {TimeUnit.MILLISECONDS.sleep(100 + rand.nextInt(500));// Make toastToast t = new Toast(count++);print(t);// Insert into queue
        toastQueue.put(t);}} catch(InterruptedException e) {print("Toaster interrupted");}print("Toaster off");}
}// Apply butter to toast:
class Butterer implements Runnable {private ToastQueue dryQueue, butteredQueue;public Butterer(ToastQueue dry, ToastQueue buttered) {dryQueue = dry;butteredQueue = buttered;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = dryQueue.take();t.butter();print(t);butteredQueue.put(t);}} catch(InterruptedException e) {print("Butterer interrupted");}print("Butterer off");}
}// Apply jam to buttered toast:
class Jammer implements Runnable {private ToastQueue butteredQueue, finishedQueue;public Jammer(ToastQueue buttered, ToastQueue finished) {butteredQueue = buttered;finishedQueue = finished;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = butteredQueue.take();t.jam();print(t);finishedQueue.put(t);}} catch(InterruptedException e) {print("Jammer interrupted");}print("Jammer off");}
}// Consume the toast:
class Eater implements Runnable {private ToastQueue finishedQueue;private int counter = 0;public Eater(ToastQueue finished) {finishedQueue = finished;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = finishedQueue.take();// Verify that the toast is coming in order,// and that all pieces are getting jammed:if(t.getId() != counter++ ||t.getStatus() != Toast.Status.JAMMED) {print(">>>> Error: " + t);System.exit(1);} elseprint("Chomp! " + t);}} catch(InterruptedException e) {print("Eater interrupted");}print("Eater off");}
}public class ToastOMatic {public static void main(String[] args) throws Exception {ToastQueue dryQueue = new ToastQueue(),butteredQueue = new ToastQueue(),finishedQueue = new ToastQueue();ExecutorService exec = Executors.newCachedThreadPool();exec.execute(new Toaster(dryQueue));exec.execute(new Butterer(dryQueue, butteredQueue));exec.execute(new Jammer(butteredQueue, finishedQueue));exec.execute(new Eater(finishedQueue));TimeUnit.SECONDS.sleep(5);exec.shutdownNow();}
} /* (Execute to see output) *///:~

//: concurrency/E29_ToastOMatic2.java
/********************** Exercise 29 ************************ Modify ToastOMatic.java to create peanut butter and jelly* on toast sandwiches using two separate assembly lines * (one for peanut butter, the second for jelly, then* merging the two lines).
*********************************************************/
package concurrency;
import java.util.concurrent.*;
import java.util.*;
import static net.mindview.utill.Print.*;class Toast {public enum Status { DRY,BUTTERED,JAMMED,READY {public String toString() {returnBUTTERED.toString() + " & " + JAMMED.toString();}}}private Status status = Status.DRY;private final int id;public Toast(int idn) { id = idn; }public void butter() {status =(status == Status.DRY) ? Status.BUTTERED :Status.READY;}public void jam() {status =(status == Status.DRY) ? Status.JAMMED :Status.READY;}public Status getStatus() { return status; }public int getId() { return id; }public String toString() {return "Toast " + id + ": " + status;}
}class ToastQueue extends LinkedBlockingQueue<Toast> {}class Toaster implements Runnable {private ToastQueue toastQueue;private int count;private Random rand = new Random(47);public Toaster(ToastQueue tq) { toastQueue = tq; }public void run() {try {while(!Thread.interrupted()) {TimeUnit.MILLISECONDS.sleep(100 + rand.nextInt(500));// Make toastToast t = new Toast(count++);print(t);// Insert into queue
        toastQueue.put(t);}} catch(InterruptedException e) {print("Toaster interrupted");}print("Toaster off");}
}// Apply butter to toast:
class Butterer implements Runnable {private ToastQueue inQueue, butteredQueue;public Butterer(ToastQueue in, ToastQueue buttered) {inQueue = in;butteredQueue = buttered;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = inQueue.take();t.butter();print(t);butteredQueue.put(t);}} catch(InterruptedException e) {print("Butterer interrupted");}print("Butterer off");}
}// Apply jam to toast:
class Jammer implements Runnable {private ToastQueue inQueue, jammedQueue;public Jammer(ToastQueue in, ToastQueue jammed) {inQueue = in;jammedQueue = jammed;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = inQueue.take();t.jam();print(t);jammedQueue.put(t);}} catch(InterruptedException e) {print("Jammer interrupted");}print("Jammer off");}
}// Consume the toast:
class Eater implements Runnable {private ToastQueue finishedQueue;public Eater(ToastQueue finished) {finishedQueue = finished;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = finishedQueue.take();// Verify that all pieces are ready for consumption:if(t.getStatus() != Toast.Status.READY) {print(">>>> Error: " + t);System.exit(1);} elseprint("Chomp! " + t);}} catch(InterruptedException e) {print("Eater interrupted");}print("Eater off");}
}// Outputs alternate inputs on alternate channels:
class Alternator implements Runnable {private ToastQueue inQueue, out1Queue, out2Queue;private boolean outTo2;  // control alternationpublic Alternator(ToastQueue in, ToastQueue out1,ToastQueue out2) {inQueue = in;out1Queue = out1;out2Queue = out2;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = inQueue.take();if(!outTo2)out1Queue.put(t);elseout2Queue.put(t);outTo2 = !outTo2;  // change state for next time
      }} catch(InterruptedException e) {print("Alternator interrupted");}print("Alternator off");}
}// Accepts toasts on either channel, and relays them on to
// a "single" successor
class Merger implements Runnable {private ToastQueue in1Queue, in2Queue, toBeButteredQueue,toBeJammedQueue, finishedQueue;public Merger(ToastQueue in1, ToastQueue in2,ToastQueue toBeButtered, ToastQueue toBeJammed,ToastQueue finished) {in1Queue = in1;in2Queue = in2;toBeButteredQueue = toBeButtered;toBeJammedQueue = toBeJammed;finishedQueue = finished;}public void run() {try {while(!Thread.interrupted()) {// Blocks until next piece of toast is available:Toast t = null;while(t == null) {t = in1Queue.poll(50, TimeUnit.MILLISECONDS);if(t != null)break;t = in2Queue.poll(50, TimeUnit.MILLISECONDS);}// Relay toast onto the proper queueswitch(t.getStatus()) {case BUTTERED:toBeJammedQueue.put(t);break;case JAMMED:toBeButteredQueue.put(t);break;default:finishedQueue.put(t);}}} catch(InterruptedException e) {print("Merger interrupted");}print("Merger off");}
}public class E29_ToastOMatic2 {public static void main(String[] args) throws Exception {ToastQueue dryQueue = new ToastQueue(),butteredQueue = new ToastQueue(),toBeButteredQueue = new ToastQueue(),jammedQueue = new ToastQueue(),toBeJammedQueue = new ToastQueue(),finishedQueue = new ToastQueue();ExecutorService exec = Executors.newCachedThreadPool();exec.execute(new Toaster(dryQueue));exec.execute(new Alternator(dryQueue, toBeButteredQueue,toBeJammedQueue));exec.execute(new Butterer(toBeButteredQueue, butteredQueue));exec.execute(new Jammer(toBeJammedQueue, jammedQueue));exec.execute(new Merger(butteredQueue , jammedQueue,toBeButteredQueue, toBeJammedQueue, finishedQueue));exec.execute(new Eater(finishedQueue));TimeUnit.SECONDS.sleep(5);exec.shutdownNow();}
} /* (Execute to see output) *///:~