Command prompt inside a java program

Question

So I want to make a java application which, while running, can run custom commands (not windows commands, commands for my application) from the command line, I can already do it, but I'd like to have a prompt such as > where you'd type commands, how can I output > and then remove it when it's time to print something else to that line?

I'm probably not describing this clearly, I mean, so that at the bottom of all the output there's a > and you'd type commands on the right side of it, so it looks like a prompt. — James T
– James T, Commented Oct 27, 2011 at 15:35
If that > needs to be removed from the console after executing the command, maybe using the backspace character (ASCII code 8) could work? Seems hacky, but who knows. — G_H
– G_H, Commented Oct 27, 2011 at 15:38
So far, @G_H has the best suggestion. Feel free to post it as a answer G_H, — James T
– James T, Commented Oct 27, 2011 at 15:59

Community · Accepted Answer · 2020-06-20 09:12:55Z

6

On Java 6, you can use the Console class for that. Specifically, the readLine method. From the API:

public String readLine(String fmt, Object... args)
   Provides a formatted prompt, then reads a single line of text from the console. 

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Oct 27, 2011 at 15:34

PaoloVictor

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Comments

jpredham · Accepted Answer · 2011-10-27 15:41:25Z

1

I agree with PaoloVictor's recommendation of using Console, but if you're more curious about architecture I might suggest a REPL (Read, Evaluate, Print Loop). Where you would do something like this.

init();
while(1){

   System.out.print("myProgram>");
   String cmd = Console.readLine(String fmt, Object... args);
   evaluate(cmd);
}

answered Oct 27, 2011 at 15:41

jpredham

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Comments

James T · Accepted Answer · 2011-10-27 16:33:42Z

0

I found a good library, JLine, does exactly what I want.

answered Oct 27, 2011 at 16:33

James T

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