Java : Task 3 Completely concurrent. Added countdown latch

Author: roopansh

JavaProgramming/src/task3/teastall/Constants.java

@@ -1,5 +1,6 @@
 package task3.teastall;
 
+import java.time.format.DateTimeFormatter;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -9,6 +10,8 @@ public class Constants {
     public static final int SERVER_PORT = 5000;
     public static final String GET_AVAILABLE_LIST = "GET_AVAILABLE_LIST";
     public static final String PLACE_ORDER = "PLACE_ORDER";
+    public static final int ORDERS_THRESHHOLD = 10;
+    public static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("HH:mm 'on'9 cccc dd,LLLL ");
 
     public static Map<String, Integer> getInitialItems() {
         Map<String, Integer> items = new HashMap<>();

JavaProgramming/src/task3/teastall/server/ItemProcessor.java

@@ -1,16 +1,19 @@
 package task3.teastall.server;
 
+import java.util.concurrent.CountDownLatch;
+
 public class ItemProcessor extends Thread {
     private String item;
     private int quantity;
     private Server server;
     private int delay;
-
-    ItemProcessor(Server server, String item, int quantity) {
+    private CountDownLatch latch;
+    ItemProcessor(Server server, String item, int quantity, CountDownLatch latch) {
         super();
         this.item = item;
         this.server = server;
         this.quantity = quantity;
+        this.latch = latch;
     }
 
     @Override
@@ -21,6 +24,7 @@ public void run() {
             delay = this.server.getItemDelay().getOrDefault(item, -1);
             delay = delay * quantity + 2;
         }
+        latch.countDown();
     }
 
     int getDelay() {

JavaProgramming/src/task3/teastall/server/OrderProcessor.java

@@ -1,10 +1,13 @@
 package task3.teastall.server;
 
+import task3.teastall.Constants;
+
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.net.Socket;
 import java.time.LocalDateTime;
 import java.util.Map;
+import java.util.concurrent.CountDownLatch;
 
 public class OrderProcessor extends Thread {
     private Map<String, Integer> order;
@@ -28,22 +31,25 @@ public void run() {
         // Create thread for all the items and join on them
         ItemProcessor[] itemProcessors = new ItemProcessor[order.size()];
         int count = 0;
+        CountDownLatch latch = new CountDownLatch(order.size());
+
         for (Map.Entry<String, Integer> entry : order.entrySet()) {
-            itemProcessors[count] = new ItemProcessor(server, entry.getKey(), entry.getValue());
+            itemProcessors[count] = new ItemProcessor(server, entry.getKey(), entry.getValue(), latch);
             itemProcessors[count].start();
             count++;
         }
-        for (ItemProcessor itemProcessor : itemProcessors) {
-            try {
-                itemProcessor.join();
-                int d = itemProcessor.getDelay();
 
-                // check if the order can be fulfilled or not
-                if (d < 0) available = false;
-                if (delay < d) delay = d;
-            } catch (InterruptedException e) {
-                e.printStackTrace();
-            }
+        try {
+            latch.await();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        for (ItemProcessor itemProcessor : itemProcessors) {
+            int d = itemProcessor.getDelay();
+            // check if the order can be fulfilled or not
+            if (d < 0) available = false;
+            if (delay < d) delay = d;
         }
     }
 
@@ -69,7 +75,7 @@ LocalDateTime sendResult(LocalDateTime timeStamp) {
             timeStamp = timeStamp.plusMinutes(getDelay());
             try {
                 if (dataOutputStream != null) {
-                    dataOutputStream.writeUTF("The order will be delivered at " + timeStamp.toString() + ".");
+                    dataOutputStream.writeUTF("The order will be delivered by " + timeStamp.format(Constants.DATE_TIME_FORMATTER));
                 }
             } catch (IOException e) {
                 e.printStackTrace();

JavaProgramming/src/task3/teastall/server/OrdersProcessor.java

@@ -1,5 +1,7 @@
 package task3.teastall.server;
 
+import task3.teastall.Constants;
+
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
@@ -20,12 +22,13 @@ public class OrdersProcessor extends Thread {
     public void run() {
         while (true) {
             if (orders.size() > 0) {
-                while (orders.size() > 0) {
+                int count = 0;
+                while (orders.size() > 0 && count < Constants.ORDERS_THRESHHOLD) {
                     OrderProcessor order = orders.get(0);
                     orders.remove(0);
                     processingOrders.add(order);
                     order.start();
-
+                    count++;
                 }
                 while (processingOrders.size() > 0) {
                     OrderProcessor order = processingOrders.get(0);