Develop Reference

Using java to open a web browser on another computer

So, this is a rather unusual question, and I can't find anything else anywhere which has been helpful on how to do this, or if its even possible to do so.
I'm working on a game server wrote in java, and I'm trying to get the users default web browser to open to a specific link, when a command is typed into the chat box and sent to the server.
The current Issue I have is, when a user issues the command, it opens the browser on the host system, and not the players system.
I haven't been able to try any other methods, as I am unable to find any information regarding my specific situation!
#CommandHandlerMethod(accessLevel = EAccessLevel.USER)
public static Object[] vote(final Player player, final String... params) {
try {
Desktop desktop = java.awt.Desktop.getDesktop();
URI oURL = new URI("www.example.com");
desktop.browse(oURL);
} catch (Exception e) {
e.printStackTrace();
}
return AbstractCommandHandler.getAcceptResult("");
}
What I was hoping for via this code, was to open the web browser on the players system to allow them to view a specific webpage, but this has not been the case, and opens it on the server host system.

PrintService in java wont work once hosted in heroku

I have this printService snippet written :
public class MainTest {
public static void main(String[] args) {
DocFlavor flavor = DocFlavor.SERVICE_FORMATTED.PRINTABLE;
//PrintService defPrnSrvc = PrintServiceLookup.lookupDefaultPrintService();
PrintRequestAttributeSet aset = new HashPrintRequestAttributeSet();
PrintService[] services = PrintServiceLookup.lookupPrintServices(null, null);
System.out.println("my printer found: " + services.length);
// this step is necessary because I have several printers configured
for (int i = 0; i < services.length; i++) {
String svcName = services[i].toString();
//
}
}
}
But when I host it in heroku, it does not show any printer, I know the reason, that the printer service looks in your local system, thus it wont work on heroku, but is there a workaround to this, like if I send some details from my local, like IP address or Mac address of my computer then it can search the printers in that computer?
Is there a way how to pass parameters to printservice class to get the printers of a particular computer? Or does it always looks in localhost.

Interesting. I don't think Heroku has plugins for connecting to local devices in a given location, but here's a couple of ideas:
If your printer is cloud enabled, you can check the manufacturer docs of the printer to see whether there's a way to connect remotely. Probably involves flipping a setting on the printer(s) itself too.
Have you looked into Google's project for this, and does it work for your use case? https://www.google.com/cloudprint/#printers
This is the long way around, but you could probably hook up a Raspberry Pi to the printer, and use it to host an API endpoint so the pi can receive document data and any instructions you need, then pass it to the local printer via the local connection.
Hope this helps!

Sending messages from pc via mobile phone using java

I am working on an application, using java, that has the following features:
User connects his mobile to a PC using a usb cable or bluetooth.
User types a message on his PC (in the textfield provided by my software).
User types a phone number (in a textbox provided by my software).
User clicks the send button.
Then, the software should send the message to the specified phone number and appropriate charges should be applied to my mobile balance. In other words, I am directing my mobile through my software to send message to a specified number.
How shall i do that? Is core java sufficient for this purpose or i have to use j2me or is there any particular java framework that would be suitable for this?

One option is to connect the phone to the pc using serial link (COM). Need to configure the phone connected physically by USB or Bluetooth in order to appear in a COM (serial) port.
Then you need to create an application for PC (Java or whatever can open serial ports) that opens the COM port used by the phone and send the proper AT commands. Serial port can be opened by JavaComm 2.0 Win32 or more recently RxTx.
Open the serial port and write and read command by writing and reading bytes, in the same way a socket.
Then create a visual application that let user set the information like phone number for destination, text...
You need Java SE or whatever language allows you to create visual applications and opening serial ports (Java, .NET, Python...).
Some links about AT commands by serial port in Windows: 1, 2, 3.
Another option could be using native API from the mobile OS through a socket, but seems complex and using AT commands and serial port should work for all phones and the only problem is connecting the phone by serial over USB or BlueTooth and managing the serial port.

This is highly dependent on the Mobile OS you're using. Are you using Windows Mobile, Android OS, BlackBerry OS?
If you're using Android, then you should use the built in SmsManager to do that. The SmsManager can do the following:
Manages SMS operations such as sending data, text, and pdu SMS messages.
Update:
Since you're using Symbian OS, then check out the documentation for more information on sending SMS messages. I assume that you can figure out the rest (i.e. how to get the text fields for the number and the message, etc.)
Here is an example from the Symbian OS documentation:
public boolean sendSms(String number, String message){
boolean result = true;
try {
//sets address to send message
String addr = "sms://"+number;
// opens connection
MessageConnection conn = (MessageConnection) Connector.open(addr);
// prepares text message
TextMessage msg =
(TextMessage)conn.newMessage(MessageConnection.TEXT_MESSAGE);
//set text
msg.setPayloadText(message);
// send message
conn.send(msg);
conn.close();
} catch (SecurityException se) {
// probably the user has not allowed to send sms
// you may want to handle this differently
result = false;
} catch (Exception e) {
result = false;
}
return result;
}
The above snippet came from the guide on "How to Send Text SMS in Java ME"

How can I make a java applet connect with a server?

Please excuse my noobishness as I am teaching myself Java and don't know a lot.
I'm trying to make a multiplayer game that runs from Java applets, I have a server-side program working that will accept strings of text, but all my attempts to find code for applets have failed.
My best attempt looks like it works but I think fails to connect to the server, any ideas why? (localIP is my correct IP and works fine in other tests)
public void init()
{
try
{
socket = new Socket(localIP, 5555);
inStream = new DataInputStream(socket.getInputStream());
outStream = new PrintStream(socket.getOutputStream());
}
catch(Exception e)
{
never reached
}
}
I don't mind scrapping this if someone can tell me a better way to do it or any way at all.

a java applet can only connect to the server from which it was downloaded. if you are not loading the applet from localIP, then you will not be able to connect to it.
you may be able to get around this restriction by signing the applet.

Given that you are not using the Http Protocol, One assumes that the applet is loaded from another port other than 5555. If this is the case, the applet needs to be signed in order to do this functionality.

How can I emulate a COM port, write data to it and read data from it?

I'm trying to test my code that reads from a USB port (COM25 when the device is connected) that is created when a device is connected to my computer and to a boat. I cannot power the USB device when not on the boat so testing is difficult. Can someone let me know how to simulate a COM port and write data to it so my test program is able to connect to that simulated COM port and read that data?
I'm reading this from a Java program but the simulation doesn't need to be in Java or any specific language. Just a program that will simulate the COM port and allow me to connect to it. I downloaded a COM port emulator from AGG Software and it appears that it's writing to what I deem COM25 but I'm not able to connect to it from my Java test.

The general answer for this kind of problem is to wrap the code that talks to the COM port in a class that implements an interface. If you do this as a Facade (pattern) then you can also make the COM methods you call sensible from your end.
The interface can then be mocked or faked for the test. (There is a great article on test objects, but I haven't been able to find it yet.) One advantage here is that you can create a fake version that throws exceptions or otherwise does things that are possible for the port to do but hard to get it to do in practice.

Where I work, we solved a similar issue by having our emulator not spoof a COM port at all. Here's how you can do it:
Define an interface for talking with your COM port, something like IUsbCommService
Implement your real COM-communcation service, using the standard Java Comm API
For your emulator, simply kick of a thread that spits out the same sort of data you can expect from your USB device at regular intervals.
Use your IOC framework of choice (e.g., Spring) to wire up either the emulator or the real service.
As long as you hide your implementation logic appropriately, and as long as you code to your interface, your service-consumer code won't care whether it's talking to the real USB device or to the emulator.
For example:
import yourpackage.InaccessibleDeviceException;
import yourpackage.NoDataAvailableException;
public interface IUsbProviderService {
public void initDevice() throws InaccessibleDeviceException;
public UsbData getUsbData()
throws InaccessibleDeviceException, NoDataAvailableException;
}
// The real service
import javax.comm.SerialPort; //....and the rest of the java comm API
public class UsbService implements IUsbProviderService {
.
.
.
}
// The emulator
public class UsbServiceEmulator implements IUsbProviderService {
private Thread listenerThread;
private static final Long WAITTIMEMS = 10L;
private String usbData;
public UsbServiceEmulator(long maxWaitTime) throws InaccessibleDeviceException{
initialize();
boolean success = false;
long slept = 0;
while (!success && slept < maxWaitTime) {
Thread.sleep(WAITTIMEMS);
slept += WAITTIMEMS;
}
}
private void initialize() throws InaccessibleDeviceException{
listenerThread = new Thread();
listenerThread.start();
}
private class UsbRunner implements Runnable {
private String[] lines = {"Data line 1", "Data line 2", "Data line 3"};
public void run() {
int line = 0;
while(true) {
serialEvent(lines[line]);
if(line == 3) {
line = 0;
} else {
line++;
}
try {
Thread.sleep(200);
} catch (InterruptedException e) {
//handle the error
}
}
private void serialEvent(String line) {
if(/*you have detected you have enough data */) {
synchronized(this) {
usbData = parser.getUsbData();
}
}
}
}
Hope this helps!

Thanks to all the answers so far! Here's what I ended up doing as a result of recommendations from someone at work.
Downloaded the COM Port Data Emulator (CPDE) from AGG Software
Downloaded the Virtual Serial Port Driver (VSPD) from Eltima Software
(I just randomly picked a free data emulator and virtual serial port package. There are plenty of alternatives out there)
Using VSPD, created virtual serial ports 24 and 25 and connected them via a virtual null modem cable. This effectively creates a write port at 24 and a read port at 25.
Ran the CPDE, connected to 24 and started writing my test data.
Ran my test program, connected to 25 and was able to read the test data from it

There are plenty of relevant answers in this section. But as for me, I personally use Virtual Serial Port Driver, which works perfect for me. But I must admit that there are plenty alternatives when it comes to creating virtual ports: freevirtualserialports.com; comOcom to name a few. But I haven't got a chance to use them, so my recommendation for solving this problem is Virtual Serial Port Driver.

I recommend fabulatech's virtual modem.
Get it at http://www.virtual-modem.com
You might also want to get a COM port monitor for your tests - You can find it at
http://www.serial-port-monitor.com
Good luck with the boat! :)

I use com0com and it works great for what I need.

In addition all others, I would like to added this nice, free emulator https://sites.google.com/site/terminalbpp/ I do use. I do also use AGG Com port data emulator.