Name: eyC74480 Date: 03/10/98


java.lang.UNIXProcess always waits for 1 second.
(in both JDK1.1.x and JDK1.2).

ProcessInputStream within UNIXProcess never flushes
any read data.
So user of UNIXProcess has to wait for timeout(1 second).
This is default manner of java.io.PipedInputStream#receive(int).

Following is a patch for UNIXProcess.java.
*** UNIXProcess.java.orig Tue Jan 13 11:26:04 1998
--- UNIXProcess.java Tue Mar 10 14:51:45 1998
***************
*** 326,331 ****
--- 326,332 ----
   if ((nread = ins.read(buf)) < 0)
   break;
   outs.write(buf, 0, nread);
+ outs.flush();
   } catch (IOException e) {
   break;
   }

if you do this patch,
it works well.
!qv
Following program is a test program.
If you do the program,
you see that output of echo is always waiting for 1 sec.
Once you do above patch,
you will see the output is no longer waiting.


import java.io.*;

public class UNIXProcessTest {
    public static void main(String[] args) {
try {
String[] commandArray = { "echo.pl" };
String[] inputStrings = { "abc", "def", "ghi" };
Process process = Runtime.getRuntime().exec(commandArray);
DataInputStream in
= new DataInputStream(process.getInputStream());
PrintStream out
= new PrintStream(process.getOutputStream());

int i = 0;
int j = 0;
while (i < 10) {
System.out.println("sending : "+inputStrings[j]);
System.out.flush();
out.println(inputStrings[j]);
out.flush();
String line = in.readLine();
System.out.println("received : "+line);
System.out.flush();
j++;
if (j >= inputStrings.length) {
j = 0;
i++;
}
}
out.close();
} catch (IOException e) {
e.printStackTrace();
}
    }
}
(Review ID: 26299)
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