Question

As title says, mock code to demostrate my problem

Driver Class

  import java.io.*;

    public class driver
    {

        public static void main(String[] args)
        {
            PipedWriter writer1 = new PipedWriter();
            PipedWriter writer2 = new PipedWriter();
            PipedReader reader1 = new PipedReader();
            PipedReader reader2 = new PipedReader();

            Thread thread1 = new MyThread(writer1, reader1);
            Thread thread2 = new MyThread(writer2, reader2);
            try
            {
                  writer2.connect(reader1);
             } catch(Exception e)
             {
                  e.printStackTrace();
             }
        }
    }

MyThread Class

 import java.io.*;
public class MyThread extends Thread
{
    PipedReader input = new PipedReader();
    PipedWriter output = new PipedWriter();

    public MyThread(PipedWriter input, PipedReader output)
    {
        try
        {
            this.input.connect(input);
            this.output.connect(output);
        } catch(Exception e)
        {
            e.printStackTrace();            
               }
    }
    public void run()
    {
        try
        {
            input.close();
            output.close();
        }catch(Exception e)
        {
            e.printStackTrace();
        }
    }
}

I’m not sure if the .connect method is what I should be using. What I want to do is have the output stream coming from the first thread writing straight into the input stream of the second.

The code above compiles fine but says its already connected otherwise.

java.io.IOException: Already connected
        at java.io.PipedWriter.connect(Unknown Source)
        at driver.main(driver.java:17)

Answer 1

If a writer is connected to a reader, the reader is also connected to the writer. You don’t need to connect them twice. And if one thread writes and the other reads, you just need one writer and one reader.

Create both in the main thread, connect them, then creat one thread with the reader and one with the writer, and start both threads.