Equivalent to const from PHP in Java

Question

I am porting a lot of code from PHP to Java (an Android application). Everything is done but I am facing a problem here,

I got this PHP code:

class SenderKeyGroupData{
  const MESSAGE = 1;
  const SENDER_KEY = 2;
  /* @var array Field descriptors */
  protected static $fields = array(
      self::MESSAGE => array(
        'name' => 'message',
        'required' => false,
        'type' => 7,
      ),
      self::SENDER_KEY => array(
          'name' => 'sender_key',
          'required' => false,
          'type' => "SenderKeyGroupMessage",
      ),
  );

However I want this code in Java, for example I created this Java code:

class SenderKeyGroupData {
    int MESSAGE = 1; // Must be const
    int SENDER_KEY = 2; // Must be const

    // These two Maps must be in the $fields array?
    Map MESSAGE = new HashMap(); //Duplicate conflict here
    MESSAGE.put("name", "message");
    MESSAGE.put("required", false); // Map can't contain booleans?
    MESSAGE.put("type", "7");

    Map SENDER_KEY = new HashMap(); //Duplicate conflict here
    SENDER_KEY.put("name", "sender_key");
    SENDER_KEY.put("required", false); // Map can't contain booleans?
    SENDER_KEY.put("type", "SenderKeyGroupMessage");
}

I described the problems as comments. All ideas are welcome.

Note that the const contain 1 and 2 as value in the constructor, but also get an array assigned. So please give an example instead of pointing it as duplicate.

If what you describe in the comments are the problems, then there is not one, but more. If it's the const question, then swidmann's comment above answers it. — Whirl Mind, Nov 06 '15 at 16:28
This is pretty straight forward stuff, what is unclear about the error message? You can't have two variables with the same name. Once I fix that issue, your code compiles. Not sure what you're saying about "Map can't contain booleans". — tnw, Nov 06 '15 at 16:29
You need to read Java basics. Or you will face a lot errors like this. — lewkka, Nov 06 '15 at 16:53

score 0 · Answer 1 · answered Nov 06 '15 at 16:28

I don't really know how and where you need to access these variables or how you intend to use this class but this at least compiles:

class SenderKeyGroupData {

    public static final int MESSAGE = 1;    // final keyword means it cannot be changed
    public static final int SENDER_KEY = 2; // public keyword means it can be accessed by anyone

    static Map MESSAGE_MAP = new HashMap(); // static means this is shared between all instances
    static {
        MESSAGE_MAP.put("name", "message");
        MESSAGE_MAP.put("required", false);
        MESSAGE_MAP.put("type", "7");
    }

    static Map SENDER_KEY_MAP = new HashMap();
    static {
        SENDER_KEY_MAP.put("name", "sender_key");
        SENDER_KEY_MAP.put("required", false);
        SENDER_KEY_MAP.put("type", "SenderKeyGroupMessage");
    }
}

Thank you! I never knew I could use a Map without parameters too! — gi097, Nov 06 '15 at 16:36

Equivalent to const from PHP in Java

1 Answers1