Producer And Consumer Example In Java Using Threads

     Below I have created on sample example of producer and consumer using java threads. I this example I have one producer thread which will create 50 fruit items and it will be consumed by 3 consumer threads. When producer finishes consumer also finishes the execution.Producer will create the fruit and will put it in the bucket which will be consumed by the consumer.

Below is the example :
How to run :
1)Create class ProducerConsumer in eclipse. This class contains all the other classes as inner classes.
2)Run the class and check the console.
3)Most important go though the code.

import java.util.ArrayList;
import java.util.List;

/**
 * Producer and consumer example. There will be one producer thread which will create 50 fruit items
 * and it will be consumed by 3 consumer threads. When producer finishes consumer also finishes the
 * execution
 * @author Vikram
 *
 */
public class ProducerConsumer {

public void initlize() {
Bucket b = new Bucket();
Producer producer = new Producer(b);
Consumer consumer_1 = new Consumer(b,"Consumer 1");
Consumer consumer_2 = new Consumer(b,"Consumer 2");
Consumer consumer_3 = new Consumer(b,"Consumer 3");

producer.start();
consumer_1.start();
consumer_2.start();
consumer_3.start();

}

public static void main(String[] args) {
new ProducerConsumer().initlize();
}

public class Producer extends Thread {

Bucket bucket;

public Producer(Bucket b) {
bucket = b;
}

@Override
public void run() {

int fruitCount = 0;
while (fruitCount < 50) {
synchronized (bucket) {
System.out.println("produced : Fruit_" + fruitCount);
bucket.addFruit("Fruit_" + fruitCount++);

bucket.notifyAll();

}
try {
this.sleep(200);//sleep for some so it will slow sysout slowly
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
synchronized (bucket) {
bucket.setProducerFinished(true);
bucket.notifyAll();//realese all locks befor finish
}
System.out.println("Producer finised" );

}
}

public class Consumer extends Thread {

Bucket bucket;
String consumerName;

public Consumer(Bucket b, String consName) {
bucket = b;
consumerName =consName;
}

@Override
public void run() {

while (bucket.isProducerFinished()==false ) {
synchronized (bucket) {

String fruit = bucket.getFruit();

//no fruit produced
if (fruit == null) {
try {
bucket.wait();
System.out.println(consumerName+"  waiting" );
} catch (InterruptedException e) {
e.printStackTrace();
}
}else{
System.out.println("Consumed fruit :" + fruit +" by "+consumerName);
}


}
}
synchronized (bucket) {
bucket.notifyAll();//realese all locks befor finish
System.out.println(consumerName +" finised" );
}

}

}

public class Bucket {

private List<String> fruitBuket  = new ArrayList<String>();
private boolean producerFinished = false;


public boolean isProducerFinished() {
return producerFinished;
}

public void setProducerFinished(boolean producerFinished) {
this.producerFinished = producerFinished;
}

public int getBucketSize() {
return fruitBuket.size();
}

public void addFruit(String fruit) {
fruitBuket.add(fruit);
}

public String getFruit() {
if (fruitBuket.size() == 0)
return null;
return fruitBuket.remove(fruitBuket.size() - 1);
}
}

}

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