How to implement program flow control?

[volcano]

hello, I have a problem. Hope that you can do me a favour. Thanks

I have written a java application. there are mainly 2 sentences inside it, as shown below:

Runtime.getRuntim().exec("WRITE_SOMETHING_TO_A_FILE.exe"
Runtime.getRuntim().exec("READ_THOSE_THINGS_AND_PROCESS.exe"

The problem is that the first command may need a lot of time to process. But then the second command has begun to run without waiting for the finish of the first command. So may I ask if there is any method to let first command finish and then run the second one?

thanks

 

[greeneka]

Hi Volcano,

if you hold on to the reference of the

Process

object that the

exec()

function returns you can call the

waitFor()

function on that process to suspend execution until it finishes - for example:

import java.io.*;
public class testexec{
	public static void main(String[] args){
		try{
			Process p1 = Runtime.getRuntime().exec("...");
			System.out.println("about to wait");
			p1.waitFor();
			System.out.println("finished waiting");	
		}catch(IOException ioex){
			ioex.printStackTrace();
		}catch(InterruptedException iex){
			iex.printStackTrace();
		}
	}
}

 

[volcano]

Great! It works! Thanks greeneka~