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/**
* @version 1.20 1999-04-23
* @author Cay Horstmann
*/
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.util.Random;
public class PipeTest {
public static void main(String args[]) {
try { /* set up pipes */
PipedOutputStream pout1 = new PipedOutputStream();
PipedInputStream pin1 = new PipedInputStream(pout1);
PipedOutputStream pout2 = new PipedOutputStream();
PipedInputStream pin2 = new PipedInputStream(pout2);
/* construct threads */
Producer prod = new Producer(pout1);
Filter filt = new Filter(pin1, pout2);
Consumer cons = new Consumer(pin2);
/* start threads */
prod.start();
filt.start();
cons.start();
} catch (IOException e) {
}
}
}
class Producer extends Thread {
public Producer(OutputStream os) {
out = new DataOutputStream(os);
}
public void run() {
while (true) {
try {
double num = rand.nextDouble();
out.writeDouble(num);
out.flush();
sleep(Math.abs(rand.nextInt() % 1000));
} catch (Exception e) {
System.out.println("Error: " + e);
}
}
}
private DataOutputStream out;
private Random rand = new Random();
}
class Filter extends Thread {
public Filter(InputStream is, OutputStream os) {
in = new DataInputStream(is);
out = new DataOutputStream(os);
}
public void run() {
for (;;) {
try {
double x = in.readDouble();
total += x;
count++;
if (count != 0)
out.writeDouble(total / count);
} catch (IOException e) {
System.out.println("Error: " + e);
}
}
}
private DataInputStream in;
private DataOutputStream out;
private double total = 0;
private int count = 0;
}
class Consumer extends Thread {
public Consumer(InputStream is) {
in = new DataInputStream(is);
}
public void run() {
for (;;) {
try {
double avg = in.readDouble();
if (Math.abs(avg - old_avg) > 0.01) {
System.out.println("Current average is " + avg);
old_avg = avg;
}
} catch (IOException e) {
System.out.println("Error: " + e);
}
}
}
private double old_avg = 0;
private DataInputStream in;
}
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