Java Netbeans Error Regarding Arraylist in BufferedWriter Method

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I want to write product objects per consumer to a file based on region. This is the method:

protected static void writeRecordsToFiles(ProductConsumer[] consumers) {

        try {
            BufferedWriter[] bufferedWriters = {
                new BufferedWriter(new FileWriter("data/US_Timezones/central.txt")),
                new BufferedWriter(new FileWriter("data/US_Timezones/eastern.txt")), 
                new BufferedWriter(new FileWriter("data/US_Timezones/mountain.txt")),
                new BufferedWriter(new FileWriter("data/US_Timezones/pacific.txt"))
            };

            for (int i = 0; i < bufferedWriters.length; i++) {
                bufferedWriters[i].write(consumers[i].toString());
                bufferedWriters[i].newLine();
                bufferedWriters[i].flush();

                for (ProductProducer record : consumers[i].msgList.get()) {
                    bufferedWriters[i].write(record.toString());
                    bufferedWriters[i].newLine();
                    bufferedWriters[i].flush();
                }
                bufferedWriters[i].close();
            }
            
        } catch (IOException ex) {
            Logger.getLogger(Mp3Like1.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

For this line:

for (ProductProducer record : consumers[i].msgList.get()) {

I get the error messages in Netbeans:

msgList has protected access in ProductConsumer
method get in interface List<e> cannot be applied to given types;
required: int
found: no arguments
reason: actual and formal argument lists differ in length
where E is a type-variable:
E extends Object declared in interface List

Here is the code from the whole class, and from the rest of the classes. Thank you in advance:

package mp3like1;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;
import parallelpatterns.ProductConsumer;
import parallelpatterns.ProductProducer;

public class Mp3Like1 {

    public static void main(String[] args) {
        
        long simStartTime = System.currentTimeMillis();
        System.out.println("Simulation started at 0 secs: " + simStartTime + "\n");
        
        // 2 Producer threads...
        ProductProducer producerOne = new ProductProducer("alaskan");
        new Thread(producerOne).start();
        ProductProducer producerTwo = new ProductProducer("hawaian");
        new Thread(producerTwo).start();

        // 4 Region Consumer threads....
        ProductConsumer consumer1 = new ProductConsumer("eastern", producerOne, producerTwo, 500L);
        Thread c1 = new Thread(consumer1);
        c1.setDaemon(true);
        c1.start();
        ProductConsumer consumer2 = new ProductConsumer("central", producerOne, producerTwo, 600L);
        Thread c2 = new Thread(consumer2);
        c2.setDaemon(true);
        c2.start();
        ProductConsumer consumer3 = new ProductConsumer("mountain", producerOne, producerTwo, 700L);
        Thread c3 = new Thread(consumer3);
        c3.setDaemon(true);
        c3.start();
        ProductConsumer consumer4 = new ProductConsumer("pacific", producerOne, producerTwo, 800L);
        Thread c4 = new Thread(consumer4);
        c4.setDaemon(true);
        c4.start();

        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        try {
            System.out.println("Press a key to exit...");
            in.read();
            System.out.println("\nExiting....\n");
            in.close();
            System.out.println("\nTotal simulation runtime was: " + (System.currentTimeMillis() - simStartTime) * 1000.0 + " secs.");
        } catch (IOException ioe) {
            ioe.printStackTrace();
        } finally {
            System.out.println("\nEastern Timezone's messages: \n" + consumer1 + "\n");
            System.out.println("\nCentral Timezone's messages: \n" + consumer2 + "\n");
            System.out.println("\nMountain Timezone's messages: \n" + consumer3 + "\n");
            System.out.println("\nPacific Timezone's messages: \n" + consumer4 + "\n");
            System.exit(0);
        }
    }
    
    protected static void writeRecordsToFiles(ProductConsumer[] consumers) {

        try {
            BufferedWriter[] bufferedWriters = {
                new BufferedWriter(new FileWriter("data/US_Timezones/central.txt")),
                new BufferedWriter(new FileWriter("data/US_Timezones/eastern.txt")), 
                new BufferedWriter(new FileWriter("data/US_Timezones/mountain.txt")),
                new BufferedWriter(new FileWriter("data/US_Timezones/pacific.txt"))
            };

            for (int i = 0; i < bufferedWriters.length; i++) {
                bufferedWriters[i].write(consumers[i].toString());
                bufferedWriters[i].newLine();
                bufferedWriters[i].flush();

                for (ProductProducer record : consumers[i].msgList.get()) {
                    bufferedWriters[i].write(record.toString());
                    bufferedWriters[i].newLine();
                    bufferedWriters[i].flush();
                }
                bufferedWriters[i].close();
            }
            
        } catch (IOException ex) {
            Logger.getLogger(Mp3Like1.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}
package domain;

//import java.util.logging.Logger;

public class Product {
    private String ProductID;
    private String ProductName;
    private String ProductDescription;
    private Double weight;
    private Double cost;
    //private static final Logger LOG = Logger.getLogger(Product.class.getName());

    public Product() {
        // Init instance variables...
    }

    public Product(String prd) {

    }

    public String getProductID() {
        return ProductID;
    }

    public void setProductID(String ProductID) {
        this.ProductID = ProductID;
    }

    public String getProductName() {
        return ProductName;
    }

    public void setProductName(String ProductName) {
        this.ProductName = ProductName;
    }

    public String getProductDescription() {
        return ProductDescription;
    }

    public void setProductDescription(String ProductDescription) {
        this.ProductDescription = ProductDescription;
    }

    public Double getWeight() {
        return weight;
    }

    public void setWeight(Double weight) {
        this.weight = weight;
    }

    public Double getCost() {
        return cost;
    }

    public void setCost(Double cost) {
        this.cost = cost;
    }

    public Product(String ProductID, String ProductName, String ProductDescription, Double weight, Double cost) {
        this.ProductID = ProductID;
        this.ProductName = ProductName;
        this.ProductDescription = ProductDescription;
        this.weight = weight;
        this.cost = cost;
    }

    @Override
    public String toString() {
        return "Product{" + "ProductID=" + ProductID + ", ProductName=" + ProductName + ", ProductDescription=" + ProductDescription + ", weight=" + weight + ", cost=" + cost + '}';
    }

}

package domain;

import java.util.Date;

public class ProductMessage {
    
    private Product product;
    private Date timeStamp;
    private String region;

    public ProductMessage(Product product, Date timeStamp, String region) {
        this.product = product;
        this.timeStamp = timeStamp;
        this.region = region;
    }
    
    public ProductMessage() {}

    public Product getProduct() {
        return product;
    }

    public void setProduct(Product product) {
        this.product = product;
    }

    public Date getTimeStamp() {
        return timeStamp;
    }

    public void setTimeStamp(Date timeStamp) {
        this.timeStamp = timeStamp;
    }

    public String getRegion() {
        return region;
    }

    public void setRegion(String region) {
        this.region = region;
    }

    @Override
    public String toString() {
        return "ProductMessage{" + "product=" + product + ", timeStamp=" + timeStamp + ", region=" + region + '}';
    }
   
}

package parallelpatterns;

//file: ProductConsumer.java

import domain.ProductMessage;
import java.util.ArrayList;
import java.util.List;

public class ProductConsumer implements Runnable {
    // There are four consumers; eastern, central, mountain, and pacific...

    private ProductProducer producerOne;
    private ProductProducer producerTwo;
    private String region;
    private long sleepInterval;
    protected List<ProductMessage> msgList;

    public ProductConsumer(String region, ProductProducer producerOne, 
            ProductProducer producerTwo, long sleepInterval) {
        this.producerOne = producerOne;
        this.producerTwo = producerTwo;
        this.region = region;
        this.sleepInterval = sleepInterval;
        msgList = new ArrayList<ProductMessage>();
    }

    public void run() {
        while (true) {
            checkProducerForMessage(producerOne);
            checkProducerForMessage(producerTwo);
        }
    }
    
    protected synchronized void checkProducerForMessage(ProductProducer prd) {
        ProductMessage message = prd.getMessage(region);       
        if (message != null) {
            msgList.add(message);
            System.out.println("Consumer: " + region + " region got message: \n" + 
                    message + "\nof total " + prd.getListSize() + " messages...");
        }
        try {
            Thread.sleep(sleepInterval);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    public String toString() {
        String messageString = "";
        for (ProductMessage m : msgList) {
            messageString += m + "\n";
        }
        return messageString;
    }
}
package parallelpatterns;

import domain.Product;
import domain.ProductMessage;
import java.util.Date;
import java.util.Random;


public class ProductProducer implements Runnable {  
    
    private String prd;
    static final int MAXQUEUE = 5; 
    private java.util.List<ProductMessage> messageList;     
    /**
     *
     * @param prd
     */
    public ProductProducer(String prd){
      this.prd = prd;
      messageList = new java.util.ArrayList<ProductMessage>();
    }

    @Override
    public void run() {
        while (true) {
            putMessage();
            try {
                Thread.sleep(1000L);
            } catch (InterruptedException e) {
            }
        }
    }

    private synchronized void putMessage() {
        while (messageList.size() >= MAXQUEUE) {
            try {
                wait(500L);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        
        Random rnd = new Random();
        Product[] products = { 
            new Product("5A2C", "Widget", "The famous widget device (just a few are still available).",25.57, 99.99) , 
            new Product("7F5A", "WidgetPlusPlus", "Highly improved version of original Widget product.", 19.67, 149.49) 
        };
        rnd = new Random();
        Product rndPrd = products[rnd.nextInt(products.length)];              
        String[] regions = {"eastern", "central", "mountain", "pacific" };
        String rndReg = regions[rnd.nextInt(regions.length)];
        
        messageList.add(new ProductMessage(rndPrd, new Date(),rndReg)); 
        System.out.println("Producer: " + prd + " Queue: " + messageList.size() + " total at " + new Date());
        System.out.println("Producer: " + prd + " Queue: " + messageList.get(0).getRegion());

        notify();
    }

    // called by Consumer
    public synchronized ProductMessage getMessage(String region) {
        ProductMessage message = null;
        while (messageList.size() == 0) {
            try {
                notify();
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("Consumer " + region + " checking region value from top element of queue: " + messageList.get(0).getRegion());
        if (region.equals(messageList.get(0).getRegion())) {
            return messageList.remove(0);
        }
        notify();
        return message;
    }

    public int getListSize() {
        return messageList.size();
    }
}

Posted 21-Dec-12 8:27am

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TorstenH. · Answer 1 · 2012-12-21T23:30:00

Please be careful, you're mixing up there some things:

messageList in ProductProducer is a "native" List and only the constructor initializes it as an ArrayList. You need to make sure the specific constructor is called before using that list - or better make it an ArrayList right away.

Your loop

Java

for (ProductProducer record : consumers[i].msgList.get()) {
  // some fun
}

also inculdes a false call. ArrayList.get() or List.get() does not exist - NetBeans should have told you so. Both need an int as argument.
Maybe you have a false import in there (some GUI component called "List" ?)

EDIT: Please also check out Richards Answer in the Java Forum here, he spotted also some primary problem (the above described will be visible when Richard's find is solved).