So I want to use specific chars to move an obect, via an enum in java-CodePudding

So I've been assigned the task of making a program to move an object around a string map in java. I've been asked to use an enum with a specific char via fileresource to command movement via the ObjCommand enum.
This is what I've got so far as far as basics..., but I keep spinning my wheels in trying different things and now I am all muddled up. so here goes -

  public enum ObjCommand {

FORWARD (F),
TURN_LEFT(L),
TURN_RIGHT(R),

(Other commands...);

public char directionKey;


private ObjCommand(char directionKey){
    this.directionKey = directionKey;     
}
//public char getDirectionKey() {
 //  return DirectionKey
public final char getDirectionKey(char directionKey){
    return directionKey;
}

....I'm trying to throw in different methods such as toString, etc, which I know I'll need, but the chars(F, L, etc) just seem to not want to register as a variable and now I'm just totally confused.

I'm still learning and any help would be appreciated :)
I'm sure I'm not explaining myself properly, so here is the uml for this specific part just in case it can add any clarity to what I am trying to do here:

enum ObjCommand <<enumeration>>
  FORWARD : F
  TURN_LEFT : L
  TURN_RIGHT : R
(etc. other moves by key entry) then:
- ObjCommand(directionKey : char)
  getDirectionKey() : char

I appreciate anybody who takes the time to look at this and help a total n00b out. This part of it is driving me a little bonkers :)

CodePudding user response：

Maybe you can check this and compare to your code:

https://www.baeldung.com/java-enum-values

2nd:

Shouldn't your chars be in quotes?

FORWARD ('F'),

and a getter should not take a inpout parameter.

CodePudding user response：

In terms of getting you started with enums, you can access them via the enum name like so:

ObjCommand.TURN_LEFT

If you'd like to access via the single character strings, you can write a static function like so:

static ObjCommand getFromChar(char c) {
    switch (c) {
    case 'F':
        return ObjCommand.FORWARD;
    case 'L':
        return ObjCommand.TURN_LEFT;
    case 'R':
        return ObjCommand.TURN_RIGHT;
    default:
        throw new IllegalArgumentException("Invalid command character "  c);
    }
}

Also, concerning getDirectionKey, your current version just returns whatever value is passed in, so it has nothing to do with the enum value. It's likely what you really want is a final field directionKey and a getter that returns its value:

public char getDirectionKey() {
    return this.directionKey;
}

CodePudding user response：

Your Enum could look like this:

public enum ObjCommand {

    FORWARD('F');
    
    private final char key;
    
    private ObjCommand(char key) {
        this.key = key;
    }
    
    public char getDirectionKey() {
        return key;
    }
}

With getDirectionKey you would retrieve your key.