two programs won't synchronize! Plz help!!!

[yihyang]

Hello there.

I've been racking my fruitless brains for hours now, but I still have two huge problems with my code.

// -------- Begin: Advertisement.java ------------
class Advertisement extends Thread
{
	String msg = "";
	synchronized Advertisement(String str)
	{
		msg = str;
	}
    public void run()
    {
        while(true)
        {
            try
            {
                System.out.print(msg + " ");
                sleep(1000);
            }
            catch (InterruptedException e)
            {
				break;
            }
        }
    }
}
// --------End: Advertisement.java ------------
// -------- Begin: TestAdvt.java ------------
import java.io.*;
 
class TestAdvt
{
    public static void main (String[] args)
    {
		try
		{
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			while(true)
			{
				System.out.println("Please enter the advertisement message to be displayed (enter 'n' to exit):");
				String str = br.readLine();
				if (str == "n") break;
				else{ 
					Advertisement advt = new Advertisement(str);
					advt.start();
					System.in.read();
					advt.interrupt();}
			}
			br.close();
		}
		catch (IOException e)
		{
            System.out.println("error: " + e.getMessage());
		}
    }
}
// --------End: TestAdvt.java ------------

1. The programs aren't synchronized, so when I run it and press enter in the middle of the announcements, it keeps printing the msg + " " (I want Advertisement.java to pause until the user inputs another message)
2. For some reason, even if I enter "n" (which should allow the user to exit the program completely) the program won't go through the if-statement.

I'm a real beginner at this, so I'd really appreciate simple language (no advanced stuff)

Thank you!

[Norm]

Please edit your post and wrap your code with code tags:
[code=java]
<YOUR CODE HERE>
[/code]
to get highlighting and preserve formatting.

[yihyang]

Thank you!

[Norm]

Does the code execute the call to the interrupt() method? Add a println that prints a message to see.

The code should use the equals() method to compare Strings, not the == operator.

[yihyang]

Does the code execute the call to the interrupt() method? Add a println that prints a message to see.

I've done that (after taking out the 'synchronized' keyword in front of the Advertisement constructor), but it just prints out:

message message message
Please enter the advertisement message to be displayed:
Interrupted

and it continues to print blank messages every second...

--- Update ---

The code should use the equals() method to compare Strings, not the == operator.

Yay! The break works! thx

[yihyang]

Any suggestions??? Really need help here ><

[Norm]

Please explain what the problem is now?

[yihyang]

Please explain what the problem is now?

"Does the code execute the call to the interrupt() method? Add a println that prints a message to see."

I've done that (after taking out the 'synchronized' keyword in front of the Advertisement constructor), but it just prints out:

message message message
Please enter the advertisement message to be displayed:
Interrupted

and it continues to print blank messages every second...

[Norm]

Can you post the current version that shows the println() statements.

[yihyang]

I've taken care of the synchronizing problem (I just limited the access to the while loop in Advertisement), but now, when I run the program, starting from the second loop, the program ignores the first letter of all inputs

For example, it prints like this:
Please enter the advertisement message:
Attention
ttention ttention ttention

// -------- Begin: Advertisement.java ------------
class Advertisement extends Thread
{
	String msg = "";
 
	public Advertisement(String str) {msg = str;}
    public void run()
    {
		boolean cont = false;
		if (!msg.equals("")) cont = true;
        while(cont)
        {
            try
            {
                System.out.print(msg + " ");
                sleep(1000);
            }
            catch (InterruptedException e)
            {
				System.out.println("Interrupted");
				break;
            }
        }
    }
}
// --------End: Advertisement.java ------------
// -------- Begin: TestAdvt.java ------------
import java.io.*;
 
class TestAdvt
{
    public static void main (String[] args)
    {
		try
		{
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			while(true)
			{
				System.out.println("Please enter the advertisement message to be displayed (enter 'n' to exit):");
				String str = br.readLine();
				if (str.equals("n")) break;
				else{ 
					Advertisement advt = new Advertisement(str);
					advt.start();
					System.in.read();
					advt.interrupt();}
			}
			br.close();
		}
		catch (IOException e)
		{
            System.out.println("error: " + e.getMessage());
		}
    }
}
// --------End: TestAdvt.java ------------

[Norm]

the program ignores the first letter of all inputs

I'm not sure what reading from two different inputs will do.

System.in.read();

Here's the console when I execute it:

Please enter the advertisement message to be displayed (enter 'n' to exit):
msg1 sent interrupt at Thu Apr 04 16:59:31 EDT 2013
Please enter the advertisement message to be displayed (enter 'n' to exit):
Interrupted at Thu Apr 04 16:59:32 EDT 2013
sent interrupt at Thu Apr 04 16:59:32 EDT 2013
Please enter the advertisement message to be displayed (enter 'n' to exit):
sent interrupt at Thu Apr 04 16:59:32 EDT 2013
Please enter the advertisement message to be displayed (enter 'n' to exit):
msg2 Interrupted at Thu Apr 04 16:59:32 EDT 2013
msg3 Interrupted at Thu Apr 04 16:59:32 EDT 2013

I used this in the main() method to execute with

         System.setIn(new ByteArrayInputStream("msg1\nmsg2\nmsg3\nn\n".getBytes()));