Hello,
This is my first post to the community. I have never really been one to ask of much help but I am stumped. I was asked to asked to write a word count program that received input from a scanner object. The input could consist of one or more file names relative or absolute paths. I am very new to the concepts of threads but I do understand that in order to produce a thread you must implement runnable (and utilize the run() to execute your action) or extend the thread class. However, my problems lies in the fact that you do not have a set number of files that you are processing so you cannot flat out initialize a specific number of runnable objects for that number of threads. I got around this fact by using a loop but it uses the same variable.
I am able to read the file names and give a word count for each and everything works all fine and dandy. I am required to print a total out at the end of the program of all the words counted. I get it to print but it is only the count for the last word. I understand that this is because within my run() method for my class that implements runnable i make a call to my setter for my total within my total class. Each time I run a new thread it initializes a new instance of the Total class, which I believe is my problem because the variable is reset. I also wrote my total methods as synchronized. I am at a complete loss on how to get around this and my code still function properly. I am coming back from a three long year break without touching java and now this new concept has got be baffled. I wrote a program without using threads very very easily. If anyone has any experience with this and does not mind to give me some advice then I would be very grateful. Thanks everyone.
Here is my code:
package com.threads.dada;
public class ThreadTester
{
public static void main(String[] args)
{
final int count;
String fileName;
FileNames fn = new FileNames();
fn.setFileNames();
count = fn.count();
for(int i = 0; i <= count; i ++)
{
fileName = fn.getFileNames(i);
if(i != (count))
{
Runnable r = new Threads(fileName, false);
Thread t = new Thread(r);
t.start();
}
else
{
Runnable r = new Threads(fileName, true);
Thread t = new Thread(r);
t.start();
}
}
}
}package com.threads.dada;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Threads implements Runnable
{
public Threads(String fn, Boolean l)
{
filename = fn;
last = l;
}
@Override
public void run()
{
tot = new Total();
try
{
rf = new Scanner(new File(filename));
while(rf.hasNext())
{
rf.next();
count ++;
}
tot.setTotal(count);
if(last == false)
{
System.out.println(filename + ":" + count + " ");
}
else if(last == true)
{
System.out.println(filename + ":" + count + " ");
System.out.println("Total: " + tot.getTotal());
}
rf.close();
}
catch(FileNotFoundException e)
{
System.out.println("File " + filename + " was not found.");
}
}
private String filename;
private Boolean last;
private Scanner rf;
private int count = 0;
private Total tot;
}package com.threads.dada;
import java.util.*;
public class FileNames
{
public void setFileNames()
{
System.out.println("Enter a filename for a .txt or .java file.");
in = new Scanner(System.in);
filename = in.nextLine();
while(filename.equals(""))
{
System.out.println("If you would like to exit, please enter exit at the command prompt.\n" +
"Please re-enter a filename for a .txt or .java file.");
in = new Scanner(System.in);
filename = in.nextLine();
if(filename.equalsIgnoreCase("exit"))
{
System.exit(0);
}
}
StringTokenizer st = new StringTokenizer(filename);
count = st.countTokens();
token = new String[count];
i = 0;
while(st.hasMoreTokens())
{
token[i] = st.nextToken();
i++;
}
in.close();
}
public String getFileNames(int i)
{
return token[i];
}
public int count()
{
return (token.length - 1);
}
private Scanner in;
private String filename;
private String token[];
private int count;
private int i;
}package com.threads.dada;
public class Total
{
private int total = 0; // count starts at zero
public synchronized void setTotal(int amount)
{
total = amount;
}
public synchronized int getTotal()
{
return total;
}
}