Setting a value for Sleep from the command line

[Stuart Lord]

I am currently trying to write a class that can take a value from the command line and then cause a subsequent process to sleep for that period of time.

I have so far written the following code:

class Sleeper implements Runnable
{
	public void run()
	{
		System.out.println("Sleeper running");
		System.out.println("Run by " + Thread.currentThread().getName());
		try
			{
				Thread.sleep(1000);
			}
			catch (InterruptedException ex)
			{
			}	
	}
}
public class Sleeping
{
	public static void main (String [] args)
	{	
		int sleepTime = Integer.parseInt(args[0]);
		System.out.println("Sleeping for " + sleepTime + " Seconds");
		Sleeper sl = new Sleeper();
		Thread t = new Thread(sl);
		t.setName(args[1]);
		t.start();
	}
}

I would like to pass the value in sleepTime to the Sleeper class and have the sleep method use it as a parameter.

Can anyone suggest how this can be done? Clearly I can pass a second argument (args[1]) to Sleeper and it will use it in

System.out.println("Run by " + Thread.currentThread().getName());

this is because there is a getName() method in Thread.

Trying the following

t.setTime = sleepTime;

gives the compilation error:

Sleeping.java:25: cannot find symbol
symbol  : variable setTime
location: class java.lang.Thread
                t.setTime = sleepTime;

Any help would be greatly appreciated..

[Joanne Neal]

Give your Sleeper class a constructor that takes an int as a parameter and store that value in an instance variable. You can then use it in your run method.

[Stuart Lord]

Joanne - thanks for your help, I changed the code as you suggested and it works fine! I insert the working version, for interest, with a few minor modifications:

class Sleeper implements Runnable
{
	int Sleeping;
	Sleeper (int x) // Overloaded constructor for Sleeper 
	{
		this.Sleeping = x; // Pass value to instance variable Sleeping
	}
	public void run()
	{
		System.out.println("Sleeping is being run by " + Thread.currentThread().getName());
		try
			{
				System.out.println("Sleeping for " + (Sleeping/1000) + " Seconds");
				Thread.sleep(Sleeping);
			}
			catch (InterruptedException ex)
			{
			}	
	}
}
public class Sleeping
{
	public static void main (String [] args)
	{	
		int sleepTime = Integer.parseInt(args[0]); // Use parseInt method of Integer to convert first 
		// argument of main from String to int
		Sleeper sl = new Sleeper(sleepTime); // Create new instance of Sleeper using sleepTime as argument 
		Thread t = new Thread(sl);
		t.setName(args[1]);
		t.start();
	}
}

Just a final comment, I note that the API documentation, states that sleep expects a long. I assume it is safer therefore to use Long.parseLong in Sleeping and make corresponding changes to Sleeper..

[jishnu dasgupta]

Hi stuart,

I think it is better if the sleeping varriable be set to a long type as you would be setting the time in milliseconds and sleep() take an argument of type long!!!..