Send string from java (or other platform) to application

Question

I want to send a barcode, read with my cellphone, to my computer. My computer has a simple server running, which listens to barcodes. When a barcode arrives, the server app should be able to input the value of the received barcode into the active application (I don't really care which application is going to get the input, the user should be able to select gedit, a terminal window or the browser if they choose to).

My language at the moment is Java on GNU/Linux (Ubuntu), so I know about the Robot class. But the Robot class emulates a keyboard, which means: when you send VK_1 on a US keyboard layout, the output is '1' indeed, but when you send VK_1 on another layout (like belgian, which I use), which requires shift for the '1' key, the output is '&' (this is the character on the '1' key, when you don't hold shift).

I also found xsendkeys, but this application too requires you to specify whether you need to hold shift. So it will be able to send an 'a' but for an 'A' (thus capital) you need to specify you want to hold shift with your 'a'.

Isn't there an easy way to do this, for GNU/Linux and Windows, just using strings. I want to be able to send "12a68dd" to the active application. And I also would like to be able to send UTF-8 characters to the active application.

I have been looking for a solution, but most require the breakdown in multiple keystrokes, which are often dependent on the keyboard layout.

Answer 1

I may not have grasped your question completely, but you want to separate applications, both written in Java, to exchange information? I'd recommend you read up on RMI, which exists för that very purpose.

Answer 2

Seems like you want to be able to send an arbitrary keyboard sequence to any possible application. With that I cannot help you (you should look for "Java UI testing automation" to find any suitable tools), but if the application you are sending the string to listens for it on its standard input, I would go for:

// Example: send your string to "cat" (or "type" on Windows), which simply prints it.
Process spawned = ProcessBuilder.command("cat" /*No arguments*/).start();
spawned.getOutputStream().write(yourString.getBytes("UTF-8"));

Simple stdin/stdout redirection, in other words.

Answer 3

If I understand you correctly, you wish to send a series of characters into another application (the destination). This destination could be any application, and you may not have access to its source code.

The answer is simply no.

Key strokes differ to characters (which I gather you have probably worked out) and Robot was intended just to invoke key strokes. The resulting output of those key strokes is generally different due to the fact most keyboards used do not follow the ISO standard for keyboards.

There are often other ways of accomplishing the same affect though, through APIs, file IO, etc.

Answer 4

Just wanted to let you know my sollution:

Call xvkbd -text from java and give the text to be writen as argument. If the text contains spaces, I call xvkbd multiple times with a xvkbd -text \[space] call within.

My current way is pretty easy to 'port' to windows, so that wont be too hard to get running with a SendKeys VB application.

Thanks all for your help!