use getter to pass value failed in java

Question

I am a beginner there are two classes that I want to use getter to pass the value of the field from another class. Therefore, I did something like this How do getters and setters work?

But it didn't pass the value. I got IllegalArgumentException: bound must be greater than origin from the NimAIPlayer since its bound and origin can't be the same value. What could be the reason?

Here is part of the NimAIPlayer class

public class NimAIPlayer extends NimPlayer implements Testable {

NimGame nimGame = new NimGame();
private int stoneTaken;


public int moveStone() {
    int balance = nimGame.getStoneBalance();
    int initialStone = nimGame.getInitialStone();
    int upperBound = nimGame.getUpperBound();
    if (initialStone == balance) {
        stoneTaken = ThreadLocalRandom.current().nextInt(1, upperBound + 1);
        return stoneTaken;

    } else if (balance < upperBound){
        stoneTaken = ThreadLocalRandom.current().nextInt(1,  + balance + 1);
        return stoneTaken;

    } else if (balance >= upperBound){
        stoneTaken = ThreadLocalRandom.current().nextInt(1, upperBound + 1);
        return stoneTaken;
    }
    return -1;
}

And here is part of my NimGame class

public class NimGame extends Nimsys {

NimPlayer player1;
NimPlayer player2;

int stars;
int stoneBalance;
int initialStone;
int upperBound;
int takeStone;

public NimGame() {

}

public NimGame(NimModel nimModel, int initialStone, int upperBound , NimPlayer player1, NimPlayer player2) {
    this.initialStone = initialStone;
    this.upperBound = upperBound;
    this.player1 = player1;
    this.player2 = player2;
}

public int getInitialStone() {
    return initialStone;
}

public int getUpperBound() {
    return upperBound;
}

public int getStoneBalance() {
    return stoneBalance;
}

Any help is highly appreciated.

I called the getter in the `NimGame` to do the computation. In the `moveStone()` method. I print out all the value I get, it's all zeros. @AnishekRamanBharti — Woden, May 14 '20 at 06:08
@Ambika I have six classes to go through all the stacktrace... It would too huge. — Woden, May 14 '20 at 06:10
All fields are zero beacuse you have not initialized the fields which you are trying to get in moveStone() — Anishek Raman Bharti, May 14 '20 at 06:10
okay, is there a proper way to handle this or any articulate articles? thank you @AnishekRamanBharti — Woden, May 14 '20 at 06:15
The values will be passed in when I call the entire `NimGame` to be played. How can I use the getter to get the values? — Woden, May 14 '20 at 06:16
You can use either parameterized constructor or setter to set the values of NimGame . Once values are set , getters method can be used to get the values easily . — Anishek Raman Bharti, May 14 '20 at 06:28

score 1 · Answer 1 · answered May 14 '20 at 06:10

1

When you instantiated the nimGame class you used the default constructor which has not instantiated the values. That would make the values null. Instantiate the values in the nimGame class first.

public class NimGame extends Nimsys {

NimPlayer player1;
NimPlayer player2;

int stars;
int stoneBalance;
int initialStone;
int upperBound;
int takeStone;

public NimGame() {
stars = default_value;
stoneBalance = default_value;
initialStone = default_value;
upperBound = default_value;
takeStone = default_value;
}

public NimGame(NimModel nimModel, int initialStone, int upperBound , NimPlayer player1, NimPlayer player2) {
    this.initialStone = initialStone;
    this.upperBound = upperBound;
    this.player1 = player1;
    this.player2 = player2;
}

public int getInitialStone() {
    return initialStone;
}

public int getUpperBound() {
    return upperBound;
}

public int getStoneBalance() {
    return stoneBalance;
}

answered May 14 '20 at 06:10

chadboii_fourtwenty

82
2
13

What if the values have already been passed in? Like I already set the `initialStone` and the `upperBound` from other class. – Woden May 14 '20 at 06:14
1

were the values passed like this?NimGame nimGame = new NimGame(nimModel, initialStone, upperBound , player1, player2); – chadboii_fourtwenty May 14 '20 at 06:17
In which class do you instantiate the args? – chadboii_fourtwenty May 14 '20 at 06:26
In the class called `Nimsys`. It's the main control panel there. I use it when I want to start a game. – Woden May 14 '20 at 06:27

score 1 · Accepted Answer · answered May 14 '20 at 06:25

1

Add a parameterized constructor in NimGame class

NimGame.java

public NimGame(NimModel nimModel, int initialStone, int upperBound , NimPlayer player1, NimPlayer player2 , int stoneBalance) {
            this.initialStone = initialStone;
            this.upperBound = upperBound;
            this.player1 = player1;
            this.player2 = player2;
            this.stoneBalance = stoneBalance;

        }

NimAIPlayer.java

You can initialize NimGame object like this using parameterized constructor

NimGame nimGame = new NimGame(new NimModel(),10,15,new NimPlayer(),new NimPlayer(),8);

Using NimGame nimGame = new NimGame() will initialize all fields with default values like null for object type and 0 for int type . This will result getting 0 for all interger fields when you print inside moveStone method .

answered May 14 '20 at 06:25

Anishek Raman Bharti

189
8

Thank you, sir! I got the point. But, I've already used this instantiation to play the game. I mean, the values of the first two parameters have been set and been passed to the `NimGame` class. How can I extract the values that already instantiated? – Woden May 14 '20 at 06:39
getter method can provide that value easily . – Anishek Raman Bharti May 14 '20 at 06:50
1

NimGame nimGame = new NimGame(new NimModel(),10,15,new NimPlayer(),new NimPlayer(),8); int initialStone = nimGame.getInitialStone(); this will give 10 . – Anishek Raman Bharti May 14 '20 at 06:50

use getter to pass value failed in java

2 Answers2