Maze generator

board.java

/**
 * The Board
 * 
 * Need to generate a maze
 */
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Random;

import javax.swing.JPanel;

public class Board extends JPanel{
	private Cell[][] cells;
	private HashMap<String, Cell> walls;
	private LinkedList<String> mapKeys;
	
	private int cellWidth;
	private int cellHeight;
	
	
	public Board(int cellWidth, int cellHeight) {
	  setBackground(Color.BLACK);
	  walls = new HashMap<String, Cell>();
	  mapKeys = new LinkedList<String>();
	  
	  this.cellWidth = cellWidth;
	  this.cellHeight = cellHeight;
	  
	}
	
	public void paint(Graphics g) {
		super.paint(g);
		Graphics2D g2d = (Graphics2D) g;
		drawMaze(g2d);
	}
	
	/**
	 * Draws the maze onto the board
	 */
	public void drawMaze(Graphics2D g2d) {
		
		//int cellx = cells.length-1;
		//int celly = cells[0].length - 1;
				
		for (int i=0; i < cells.length-1; i++) {
			for (int j=0; j < cells[i].length - 1; j++) {
				if (cells[i][j] != null) {
					if (cells[i][j].isPassable()) {
						System.out.println("Row: " + i + " Column: " + j);
						g2d.setColor(Color.RED);
						g2d.drawRect(i * cellWidth, j * cellHeight, cellWidth, cellHeight);						
					}
				} else {
					//g2d.setColor(Color.BLACK);
					//g2d.drawRect(i * cellWidth, j * cellHeight, cellWidth, cellHeight);
					
					
				}
			}
		}
	}
	
	/**
	 * Creates cells and tries to generate a maze
	 */
	public void createMaze() {
		
		Random seed = new Random();
		
		int width = this.getWidth();
		int height = this.getHeight();
		
		int cellsPerRow = width/cellWidth;
		int cellsPerColumn = height/cellHeight;
		
		cells = new Cell[cellsPerRow][cellsPerColumn];

		//Pick the first cell
		Cell firstCell = new Cell(cellHeight, cellWidth, true);
		int theRow = seed.nextInt(cellsPerRow);
		int theColumn = seed.nextInt(cellsPerColumn);
		System.out.println("First row: " + theRow + " First Column: " + theColumn);
		cells[theRow][theColumn] = firstCell;
		
		//Add the adjacent walls to the map
		addAdjacentWalls(theRow, theColumn, cellWidth, cellHeight);
		
		Cell newCell = new Cell(cellHeight, cellWidth, false);
		
		/**
		 * Loop through the walls
		 */
		while (!mapKeys.isEmpty()) {
			
			//Get a random key from the Keymap
			String posKey = mapKeys.remove(seed.nextInt(mapKeys.size()));
			
			newCell = walls.get(posKey);
			
			//Split the pos string
			String parts[] = posKey.split(" ");
			theRow = Integer.parseInt(parts[0]);
			theColumn = Integer.parseInt(parts[1]);
						
			System.out.println("The Row: " + theRow);
			System.out.println("The Column: " + theColumn);
			
			//Check that the opposite cells haven't been picked
			if (!this.checkAdjacent(theRow, theColumn)) {
						
				//Add the cell to the floor map
				newCell.setPassable(true);
				cells[theRow][theColumn] = newCell;
						
				//Add the adjacent walls to the map
				addAdjacentWalls(theRow, theColumn, cellWidth, cellHeight);
			}
			
		}		
						
	}
	
	/**
	 * Checks the surrounding cells of the cell at [row][column]
	 *
	 * @param theRow
	 * @param theColumn
	 * @param cellHeight
	 * @param cellWidth
	 */
	public boolean checkAdjacent(int theRow, int theColumn) {
				
		for (int i=-1; i<2; i++) {
			for (int j=-1; j<2; j++) {
				//Check for array out of bounds exceptions
				if (!((theRow == 0 && i == -1 ) || (theColumn == 0 && j == -1))) {
					
					//Make sure the corners aren't selected.
					if (!((i+j)%2 == 0 || theRow + i > cells.length || theColumn + j > cells[theColumn].length -1)) {
				
				
						if (cells[theRow+i][theColumn+j] == null ||!cells[theRow+i][theColumn+j].isPassable()) {
							return false;
						}
					}
				}
				
			}
		}
					
		return true;
	}
	
	/**
	 * Adds the cells above, below, left and right of the cell specified by cellColumn and cellRow
	 * to the walls map
	 * 
	 * @param cellColumn
	 * @param cellRow
	 * @param cellWidth
	 * @param cellHeight
	 */
	public void addAdjacentWalls(int cellRow, int cellColumn, int cellWidth, int cellHeight) {
		
		for (int i=-1; i<2; i++) {
			for (int j=-1; j<2; j++) {
				//Check for array out of bounds exceptions
				if (!((cellRow == 0 && i == -1 ) || (cellColumn == 0 && j == -1))) {
					
					//Make sure the corners aren't selected.
					if (!((i+j)%2 == 0 || cellRow + i > cells.length || cellColumn + j > cells[cellColumn].length -1)) {
					
						Cell aWall = new Cell(cellHeight, cellWidth, false);
						
						cellRow += i;
						cellColumn += j;
						
						//Create the key
						String pos = "" + cellRow +" "+ cellColumn;
						
						//Check that the wall has not already been added.
						if (!walls.containsKey(pos)) {
							//Add the wall
							mapKeys.add(pos);
							walls.put(pos , aWall);
						} else {
							mapKeys.remove(pos);
							walls.remove(pos);
						}				
					}
				}
				
			}
				
		}
		
	}
			
}