From 5b8de98ac341b0763b20ba43e8a2753e3f572d1b Mon Sep 17 00:00:00 2001
From: Gaetano Piazzolla <gae.piaz@gmail.com>
Date: Mon, 28 Aug 2023 19:38:00 +0200
Subject: [PATCH] JAVA-23377 | fixing sync code block (#14574)

---
 .../baeldung/producerconsumer/DataQueue.java  |  4 ++
 .../baeldung/producerconsumer/Producer.java   | 46 ++++++++++++-------
 .../ProducerConsumerDemonstrator.java         |  9 ++--
 3 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/DataQueue.java b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/DataQueue.java
index 8867ddeb63..8b6f02b529 100644
--- a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/DataQueue.java
+++ b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/DataQueue.java
@@ -58,4 +58,8 @@ public class DataQueue {
             return queue.poll();
         }
     }
+
+    public Integer getSize() {
+        return queue.size();
+    }
 }
diff --git a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/Producer.java b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/Producer.java
index 5ca60a29e4..069476bbd1 100644
--- a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/Producer.java
+++ b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/Producer.java
@@ -1,12 +1,13 @@
 package com.baeldung.producerconsumer;
 
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 
 public class Producer implements Runnable {
     private static final Logger log = Logger.getLogger(Producer.class.getCanonicalName());
     private final DataQueue dataQueue;
-
     private static int idSequence = 0;
+    final ReentrantLock lock = new ReentrantLock();
 
     public Producer(DataQueue dataQueue) {
         this.dataQueue = dataQueue;
@@ -19,22 +20,38 @@ public class Producer implements Runnable {
 
     public void produce() {
         while (dataQueue.runFlag) {
-            while (dataQueue.isFull() && dataQueue.runFlag) {
-                try {
-                    dataQueue.waitOnFull();
-                } catch (InterruptedException e) {
-                    e.printStackTrace();
+
+            try {
+                lock.lock();
+
+                while (dataQueue.isFull() && dataQueue.runFlag) {
+                    try {
+                        dataQueue.waitOnFull();
+                    } catch (InterruptedException e) {
+                        e.printStackTrace();
+                        break;
+                    }
+                }
+
+                if (!dataQueue.runFlag) {
                     break;
                 }
-            }
-            if (!dataQueue.runFlag) {
-                break;
-            }
-            Message message = generateMessage();
-            dataQueue.add(message);
-            dataQueue.notifyAllForEmpty();
 
+                Message message = generateMessage();
+                dataQueue.add(message);
+                dataQueue.notifyAllForEmpty();
+
+                log.info("Size of the queue is: " + dataQueue.getSize());
+
+            }
+            finally{
+                lock.unlock();
+            }
+
+            //Sleeping on random time to make it realistic
+            ThreadUtil.sleep((long) (Math.random() * 100));
         }
+
         log.info("Producer Stopped");
     }
 
@@ -43,9 +60,6 @@ public class Producer implements Runnable {
         log.info(String.format("[%s] Generated Message. Id: %d, Data: %f%n",
                 Thread.currentThread().getName(), message.getId(), message.getData()));
 
-        //Sleeping on random time to make it realistic
-        ThreadUtil.sleep((long) (message.getData() * 100));
-
         return message;
     }
 
diff --git a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/ProducerConsumerDemonstrator.java b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/ProducerConsumerDemonstrator.java
index 96d7b9f865..eac026536d 100644
--- a/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/ProducerConsumerDemonstrator.java
+++ b/core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/producerconsumer/ProducerConsumerDemonstrator.java
@@ -36,8 +36,8 @@ public class ProducerConsumerDemonstrator {
 
     public static void demoMultipleProducersAndMultipleConsumers() {
         DataQueue dataQueue = new DataQueue(MAX_QUEUE_CAPACITY);
-        int producerCount = 3;
-        int consumerCount = 3;
+        int producerCount = 5;
+        int consumerCount = 5;
         List<Thread> threads = new ArrayList<>();
         Producer producer = new Producer(dataQueue);
         for(int i = 0; i < producerCount; i++) {
@@ -45,6 +45,7 @@ public class ProducerConsumerDemonstrator {
             producerThread.start();
             threads.add(producerThread);
         }
+
         Consumer consumer = new Consumer(dataQueue);
         for(int i = 0; i < consumerCount; i++) {
             Thread consumerThread = new Thread(consumer);
@@ -52,8 +53,8 @@ public class ProducerConsumerDemonstrator {
             threads.add(consumerThread);
         }
 
-        // let threads run for two seconds
-        sleep(2000);
+        // let threads run for ten seconds
+        sleep(10000);
 
         // Stop threads
         producer.stop();