[Ch6] GameHelper: partial refactor. Trying to simplify the logic that brute... (6ae49187) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch6/GameHelper.java

+32 −19

Changes for src/main/java/ch6/GameHelper.java: 32 added lines, 19 removed lines.
Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@ public class GameHelper {
		private static final String ALPHABET = "abcdefg";
		private static final int GRID_LENGTH = 7;
		private static final int GRID_SIZE = 49;
		private static final int MAX_ATTEMPTS = 200;

		private final int[] grid = new int[GRID_SIZE];
		private final Random random = new Random();
		@@ -23,49 +24,61 @@ public class GameHelper {
		public ArrayList<String> placeStartup(int startupSize) {
		ArrayList<String> alphaCells = new ArrayList<String>();
		// holds index to grid (0 - 48)
		int[] coords = new int[startupSize]; // current candidate coords
		int[] startupCoords = new int[startupSize]; // current candidate co-ordinates
		int attempts = 0; // current attempts counter
		boolean success = false; // flag = found a good location ?
		int location = 0; // current starting location

		startupCount++; // nth Startup to place
		int incr = 1; // set horizontal increment
		if ((startupCount % 2) == 1) { // if odd Startup (place vertically)
		incr = GRID_LENGTH; // set vertical increment
		}
		int increment = calculateIncrement();

		while (!success & attempts++ < 200) { // main search loop (32)
		location = random.nextInt(GRID_SIZE); // get random starting point
		int i = 0; // nth position in Startup to place
		while (!success & attempts++ < MAX_ATTEMPTS) { // main search loop (32)
		int location = random.nextInt(GRID_SIZE); // get random starting point
		success = true; // assume success
		int i = 0;
		while (success && i < startupSize) { // look for adjacent unused spots
		if (grid[location] == 0) { // if not already used

		coords[i++] = location; // save location
		location += incr; // try ‘next' adjacent
		if (location >= GRID_SIZE) { // out of bounds - ‘bottom'
		success = false; // failure
		}
		if (location % GRID_LENGTH == 0) { // out of bounds - right edge
		success = false; // failure
		success = startupFits(location, startupSize, increment);
		if (success) {
		startupCoords[i++] = location; // save location
		location += increment; // try ‘next' adjacent
		}
		} else { // found already used location
		success = false; // failure
		}
		}
		} // end while
		System.out.println(this);

		for (int index : coords) { // turn location into 'a0'-style coords
		grid[index] = 1; // mark master grid pts. as ‘used'
		for (int index : startupCoords) { // turn location into 'a0'-style startupCoords
		grid[index] = 1; // mark master grid position as ‘used'
		int row = index / GRID_LENGTH; // get row value
		int column = index % GRID_LENGTH; // get numeric column value

		String letter = ALPHABET.substring(column, column + 1); // convert column index to letter
		alphaCells.add(letter + row);
		}
		System.out.println(alphaCells);
		System.out.println(this);
		return alphaCells;
		}

		private boolean startupFits(int location, int startupSize, int increment) {
		int finalLocation = location + (increment * startupSize);
		if (finalLocation > GRID_SIZE \|\| finalLocation % GRID_LENGTH == 0) {
		System.out.println("location = " + location + ", startupSize = " + startupSize + ", increment = " + increment);
		return false;
		}
		return true;
		}

		private int calculateIncrement() {
		if (startupCount % 2 == 0) { // if EVEN Startup
		return 1; // place horizontally
		} else { // else ODD
		return GRID_LENGTH; // set vertical increment
		}
		}

		@Override
		public String toString() {
		StringBuilder str = new StringBuilder();