🧩 Puzzle State Example

State in action: Not every puzzle is just solved or unsolved — some have phases. A player might start it, make progress, then finally crack it.

Why it matters: Instead of messy if checks, each state gets its own class, making puzzle logic clean, extensible, and easy to follow.

Scenario

A puzzle in the escape room isn’t just “solved or unsolved.”
It might have progression:

Unsolved → Player hasn’t interacted yet.
In Progress → Player made progress (entered part of the code, found part of the clue).
Solved → Puzzle is complete.

Instead of tracking this with a boolean or lots of if statements, we give each state its own class.

PuzzleState Interface

public interface PuzzleState {
    void interact(Puzzle puzzle);
}

Concrete States

// Unsolved state
public class UnsolvedState implements PuzzleState {
    @Override
    public void interact(Puzzle puzzle) {
        System.out.println("You start working on the puzzle...");
        puzzle.setState(new InProgressState());
    }
}

// In progress state
public class InProgressState implements PuzzleState {
    @Override
    public void interact(Puzzle puzzle) {
        System.out.println("You're making progress on the puzzle...");
        puzzle.setState(new SolvedState());
    }
}

// Solved state
public class SolvedState implements PuzzleState {
    @Override
    public void interact(Puzzle puzzle) {
        System.out.println("The puzzle is already solved!");
    }
}

Puzzle Context

public class Puzzle {
    private PuzzleState state;

    public Puzzle() {
        this.state = new UnsolvedState();
    }

    public void setState(PuzzleState state) {
        this.state = state;
    }

    public void interact() {
        state.interact(this);
    }
}

Using the Puzzle State

public class EscapeRoomGame {
    public static void main(String[] args) {
        Puzzle puzzle = new Puzzle();

        puzzle.interact(); // "You start working on the puzzle..."
        puzzle.interact(); // "You're making progress on the puzzle..."
        puzzle.interact(); // "The puzzle is already solved!"
    }
}

Sample Output

You start working on the puzzle...
You're making progress on the puzzle...
The puzzle is already solved!