I'm writing an SWT application which needs to sit in the system tray and pop up automatically whenever the user connects some USB device (the application serves as its control panel).
The way to do this in the native environment (win32 in this case, but I should be platform-independent ultimately) is to listen to the WM_DEVICECHANGE event, then checking if my device has been disconnected.
Googling the subject, it seems like SWT does not in fact handle this type of event. Does anyone have any idea as to how to achieve this? My fallback solution would be sampling the USB port every n seconds, looking for the device, but this is a no-no solution as far as I'm concerned...
Thanks and cheers
Shai
EDIT: J-16 SDiZ reported that the API exists for Windows too
Here is a very good article about Access USB devices from Java applications
The described jUSB module contains a USBListener object.
Interface implemented by objects that want to monitor USB structure. The order in which these changes are reported is not necessarily going to be the order in which the changes were seen in the real world, and delays also occur.
Youre SWt object can implement this listener and do something, when the method
deviceAdded(Device dev)
is fired
Java does not provide direct interaction with the devices and with USB. There are several third-party libraries for Java that provide USB-related features (read/write from USB port). For example: http://www.icaste.com/ (commercial)
Your comment for Zorglub suggests that you have some (presumably) JNI/JNA code to call the 3rd party DLL you mentioned. I assume you could also write a JNI wrapper to the Windows API where you can register to be notified for the _WM_DEVICECHANGE_ event you mentioned.
There is a jUSB port for windows at http://www.steelbrothers.ch/jusb/
Related
I´m intending to build some java apps to be run on a raspberry pi, the main thing is that I intend them to be used with a touchscreen (not too expensive of course)
I´ve been reading about SPI communication an GPIO also, but I still have some doubts.
Can I use the SPI ports and the GPIO to both control and connect the touchscreen to the board?
in this case, Is "everything included" on raspbian? (Let me explain that) if you use the standard HDMI, my JVM will interact with raspbian to control the screen (as a standard computer screen) and the same with the touch events coming from the USB. But, as I´m not using these ports, Will I need any special libraries to be installed on raspbian? and of course, Are any?
The main problem is that I've found some libraries on c (for certain screens) but I will like to use java. If not, I will try to implement any kind of "system calls-like" interface with both java for the apps and c for the events and screen drawing.
Does all the things that I´m typing make sense?
Thanks a lot. I will appreciate any help.
yes your RaspberryPi can work with touch-screens, use JavaFX/OpenJFX. Note - you will need a compatible touch screen device (some of which are listed in the link below)
See: https://wiki.openjdk.java.net/display/OpenJFX/OpenJFX+on+the+Raspberry+Pi
There are numerous articles which explain how to handle touch events with JavaFX/OpenJFX so hopefully using the API wont be too much of a problem.
Hope that helps :)
I am trying to detect whether a wireless mouse is present on a computer. I would like my program to run in the background. I would prefer to do this in Java however if this goes beyond Java's capabilities I can use another language.
Can someone please get me started?
(This seems like a Google-able question but I cannot find anything)
This is beyond Java and is highly OS-specific. You have to query the appropriate device drivers for the operating system; for example, on Linux this would mean looking up information in the evdev system. Note that the particular "type" of wireless will matter a lot, and you may not be able to tell in any reliable way. For example, a Bluetooth mouse is always wireless, but some wireless devices connect with a USB dongle and may not be distinguishable from a wired USB device.
I wish to control my computer (and usb devices attached to the computer) at home with any computer that is connected to the internet. The computer at home must have a program installed that receives commands from any other computer that is connected to the internet. I thought it would be best if I do this with a web interface as it would not be necessary to install software on that computer. For obvious reasons it would require log in details.
Extra details: The main part of the project is actually a device that I will develop that connects to the computer's usb port. Sorry if it was a bit vague in my original question. This device will perform simple functions such as turning lights on etc. At first I will just attempt to switch the lights remotely using the internet. Later on I will add commands that can control certain aspects of the computer such as the music player. I think doing a full remote desktop connection to control my device is therefore not quite necessary. Does anybody know of any open source projects that can perform these functions?
So basically the problem is sending encrypted commands from a web interface to my computer at home. What would be the best method to achieve this and what programming languages should I use? I know Java, Python and C quite well, but have very little experience with web applications, such as Javascript and PHP.
I have looked at web chat examples as it is sort of similar concept to what I wish to achieve, except the text can be replaced with commands. Is this a viable solution or are there better alternatives?
Thank you
VNC
SSH
Remote Desktop (Windows)
You can write a WEB APPLICATION. The encryption part is solved by simple HTTPS usage. On the server side (your home computer with USB devices attached to it) you should use Python (since you're quite experienced with it) and a Python Web Framework you want (I.E. Django).
While it is an interesting programming question, perhaps you should ask it on ServerFault instead? There you can probably get a lot of nice input on web-based administration / control tools.
Unless this is a "for fun" project for you, there are about a jillion things out there that already do this. And if you want to control a computer from a web browser, be prepared to require installing some kind of custom plugin - since browsers can't touch arbitrary files on the local filesystem, execute local applications, or do other things that are flagrant security risks.
I've been using VNC for over a decade - free and easy.
http://en.wikipedia.org/wiki/Virtual_Network_Computing
Well, I think that java can work well, in fact you have to deal with system calls to manage usb devices and things like that (and as far as I know, PHP is not the best language to do this). Also shouldn't be so hard to create a basic server/client program, just use good encryption mechanism to not show commands around web.
I you are looking for solution you could use from any computer anywhere in the worls without the need to install any software on client pc, try logmein.com (http://secure.logmein.com).
It is free, reliable, works in any modern browser, you don't have to remmeber IPs and hope they won't change, ...
Or if this is a "for fun project" why not write a php script, open port 80 in your router so you can access you script from outside, possibly dynamically link some domain to your IP (http://www.dyndns.com/). In the script you would just login and then for example type the orders in textfield in some form in your script. Lets just say you want to do some command prompt stuf, so you will basically remotely construst a *.bat file for example. Then the script stores this a fromtheinternets.bat to a folder on your desktop that is being constantly monitored for changes. And when such a change is found you just activate the bat file.
Insecure? Yes (It could be made secureER)
Fun to write? Definitely
PS: I am new here, hope it's not "illegal" to post link to actual services, instead of wiki lists. This is by no means and advertisement, I am just a happy user. :)
Is there any way in Java to receive event notifications whenever link state changes on a computer (connected, disconnected, up, down, etc)? Thanks!
There is no platform-independent mechanism which accomplishes this in Java. However, you can use JNI to do it. For example, Windows allows you to poll (or be notified of) network interface states using the Network Location Awareness (NLA) API.
I'm thinking about making a physical controller (device?) with knobs, buttons, and LEDs. I'd like to interact with it using Java (respond to the knobs, light up LEDs, etc). The reason I mention Java is two-fold: first, I know Java well1. Second, I've written the rest of the program I need to interface with in Java (though there are ways to talk to the Java program from another language).
I would like the device to connect via USB and be (computer-)platform independent.
I haven't the slightest idea of where to start, except to start reading the Arduino website. Is this my best/only option? Is there something better suited for communicating with Java?
Note: I know that Arduino has something to do with Java (not sure what), but it seems like code must be written in a subset of C.
How would I get moving on this topic?
1 - No laughter, please.
The Arduino development environment is written in Java.
But the standard language you write a program for the Arduino platform is effectively C++.
The Arduino platform is based on an Atmel AVR chip. There is at least one Java VM for AVR chips. There are other languages available for the AVR such as Forth and BASIC (although I could only find commercial versions, so I'll if you want to find them, search for "AVR BASIC").
The Arduino uses a virtual COM port to communicate between the host computer and it. A virtual COM port emulates an old style serial line but is done with USB. You can use the Java communication API to then have a Java program running on the host computer communicate with your physical device.
For some encoders and buttons, you probably want to implement a USB HID device. If you're going to produce more than a couple of them, you'll want to do a custom board. Check out V-USB, an open-source library for making USB HID devices using Atmel microcontrollers. They have a bunch of examples of projects that use this library.
You could probably make this look like a HID joystick, using the encoders to produce X/Y axis information and having the buttons act like buttons. They you could use standard Java gaming APIs to read the joystick values.
Can you expand on your need for a custom device? It seems to me that designing hardware has a pretty high barrier to entry and that most applications I can think of would be better resolved by repurposing an existing piece of game controller hardware. If you really need new hardware, then i suggest you start by googling 'USB development kit' or
'USB development board' which will get you links like this, this and this.
As for working with USB hardware from Java, I've played around with the JUSB library a bit and it looks promising, but appears to be limited to Linux only because the Windows version of the native library half of the library hasn't been written. Alternatives can by found by googling 'HID java'.
Ok, computer-platform independant? What platforms are you targetting? That would depend on the driver and support for that said platform, what does the usb device do? Is it a mass storage device...You may have to look around and see if you can find a device driver that can talk to the device...
Hope this helps,
Best regards,
Tom.
I know for the serial port there were libraries that existed for interacting with it (rs232 library). Googling for java and USB returned several answers (the first was called jUSB). That would be the first type of thing I would be looking for.
sample for java usb connection to freescale microcontroller:
http://javausbapi.blogspot.com/