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Java

Posted by Lucas Santos
Lucas Santos
19,315 Points

What is Console.console = System.console();

Here is prompter.java

import java.io.Console;

//class
public class Prompter {
  private Game mGame;

  //constructor
  public Prompter(Game game){
  mGame = game;
  }

  public boolean promptForGuess(){
  Console.console = System.console();
    String guessAsString - console.readLine("Enter a letter:  ");
    char guess = guessAsString.charAt(0);
    return mGame.applyGuess(guess);
  }
}

I do not understand:

  Console.console = System.console();

I know that it's part of the java.io.Console package but why do we need it? please explain how this code works and what it allows us to do.

2 Answers

mrben
mrben
8,068 Points

The line should be:

Console console = System.console();

After doing this the console object with give you a way to interact with the console/terminal from where you ran the program. For example, taking input from the user or writing things out to the screen.

You use it in the next line (where you have a typo, btw, it should be):

String guessAsString = console.readLine("Enter a letter:  ");

Here you prompt the user with a message "Enter a letter:" and read in, from the console, whatever they type, and store it in the String variable guessAsString for later use.

Lucas Santos
Lucas Santos
19,315 Points

So what you are saying is if I did not have this code:

Console console = System.console();

Then I would not be able to use console.readLine() because it would not recognize console there for not recognizing readLine() method of the Console class?

mrben
mrben
8,068 Points

Yeah precisely.

Lucas Santos
Lucas Santos
19,315 Points

I see thanks! Seems to me that they should already automatically include the console object.

mrben
mrben
8,068 Points

No problem. To explain a little further, just in case it's useful ...

There's the Console type and that has all the methods you need.

Then there's the handy System.console() method that "Returns the unique Console object associated with the current Java virtual machine, if any".

So perhaps in theory you could be working with a console object that is not local but on a remote computer but in this program you're using the local system console.

Steve Kinsey
Steve Kinsey
4,463 Points
Steve Kinsey
Steve Kinsey
4,463 Points

Interesting info about the System.console and explains why I couldn't get it working on a Java program I wrote using JCreator (I eventually used Scanner instead, which worked fine...)

Thanks mrben