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Java Tip 65: Measure data transfer speeds via Sun's ORB in JDK 1.2 beta 4
Determine effective data transfer speeds between client and server using CORBA
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public void actionPerformed (ActionEvent evt) {
String what = evt.getActionCommand();
System.out.println ("what = " + what);
long time_start;
int n, i, size[] = {100, 500, 1000, 5000,
10000, 50000, 100000, 500000,
1000000, 5000000};
if ("send byte".equals(what)) {
byte[] array;
for (i=0; i<10; i++) {
n = size[i];
System.out.println("Allocating array: n=" + n);
try { array = new byte[n]; }
catch (java.lang.OutOfMemoryError ex) {
System.out.println("Ouch! Could not allocate:
" + n);
break;
}
time_start = System.currentTimeMillis();
viewRef.send_byte(time_start, n, array);
}
}
if ("send integer".equals(what)) {
int[] array;
for (i=0; i<10; i++) {
n = size[i];
System.out.println("Allocating array: n=" + n);
try { array = new int[n]; }
catch (java.lang.OutOfMemoryError ex) {
System.out.println("Ouch! Could not allocate:
" + n);
break;
}
time_start = System.currentTimeMillis();
viewRef.send_int(time_start, n, array);
}
}
if ("send double".equals(what)) {
double[] array;
for (i=0; i<10; i++) {
n = size[i];
System.out.println("Allocating array: n=" + n);
try { array = new double[n]; }
catch (java.lang.OutOfMemoryError ex) {
System.out.println("Ouch! Could not allocate:
" + n);
break;
}
time_start = System.currentTimeMillis();
viewRef.send_double(time_start, n, array);
}
}
if ("send float".equals(what)) {
float[] array;
for (i=0; i<10; i++) {
n = size[i];
System.out.println("Allocating array: n=" + n);
try { array = new float[n]; }
catch (java.lang.OutOfMemoryError ex) {
System.out.println("Ouch! Could not allocate:
" + n);
break;
}
time_start = System.currentTimeMillis();
viewRef.send_float(time_start, n, array);
}
}
}
}
The server consists of two java files -- one with the main() method and the other with the class that implements the methods defined in the idl file.
The main() method creates a ViewServant object, registers it with the Naming Service, and allocates one frame.
import java.applet.*;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.awt.BorderLayout;
import java.awt.event.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
public class ViewServer extends Applet {
boolean appletFlag = true;
/**
* Sets the "applet" flag which is used to determine
* whether or not this program is running as an applet.
*/
public void setAppletFlag(boolean flag) {
appletFlag = flag;
}
/**
* Calls the various methods necessary to initialize the
* program.
*/
public void init() {
// Set the layout manager
setLayout(new BorderLayout());
}
/**
* Inner class used to "kill" the window when running as
* an application.
*/
static class killAdapter extends WindowAdapter {
public void windowClosing(WindowEvent event) {
System.exit(0);
}
}
/**
* Used when running as an application.
*/
public static void main(String[] args) {
ViewServer drag = new ViewServer();
drag.setAppletFlag(false);
drag.init();
Frame frame = new Frame();
frame.setSize(400, 400);
frame.add("Center", drag);
frame.addWindowListener(new killAdapter());
frame.setVisible(true);
System.out.println ("ViewServer: contacting the ORB");
try{
// create and initialize the ORB
ORB orb = ORB.init(args, null);
// create servant and register it with the ORB
ViewServant viewRef = new ViewServant();
orb.connect(viewRef);
// get the root naming context
org.omg.CORBA.Object objRef =
orb.resolve_initial_references("NameService");
NamingContext ncRef = NamingContextHelper.narrow(objRef);
// bind the Object Reference in Naming
NameComponent nc = new NameComponent("ViewServer",
"server");
NameComponent path[] = {nc};
ncRef.rebind(path, viewRef);
// wait for invocations from clients
System.out.println ("ViewServer: waiting for clients.");
java.lang.Object sync = new java.lang.Object();
synchronized (sync) {
sync.wait();
}
} catch (Exception e) {
System.err.println("ERROR: " + e);
e.printStackTrace(System.out);
}
}
}
The ViewServant class implements the methods declared in the idl file. Each method in this class captures the current time and subtracts
the timestamp sent by the client from the current time.
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