[Ch6] GameHelper: Simplified canPlace. Broke out updating the grid into its... (f6dc2493) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch6/GameHelper.java

+39 −27

Changes for src/main/java/ch6/GameHelper.java: 39 added lines, 27 removed lines.
Original line number	Diff line number	Diff line
		@@ -32,36 +32,55 @@ public class GameHelper {
		boolean success = false; // flag = found a good location ?

		startupCount++; // nth Startup to place
		Alignment alignment = calculateIncrement();
		Alignment alignment = getAlignment();

		while (!success & attempts++ < MAX_ATTEMPTS) { // main search loop (32)
		int location = random.nextInt(GRID_SIZE); // get random starting point
		if (alignment == HORIZONTAL) {
		success = horizontalStartupFits(location, startupSize);
		} else{
		success = verticalStartupFits(location, startupSize);
		}
		boolean validLocation = isValidLocation(location, startupSize, alignment);

		if (validLocation) {
		for (int i = 0; i < startupCoords.length; i++) {
		startupCoords[i] = location =+ alignment.getIncrement();
		startupCoords[i] = location;
		location += alignment.getIncrement();
		}
		System.out.println("trying: " + Arrays.toString(startupCoords));

		if (success) {
		success = canPlaceStartup(startupCoords);
		success = allPositionsAvailable(startupCoords);
		}
		} // end while
		System.out.println(this);

		savePositionToGrid(startupCoords);
		ArrayList<String> alphaCells = convertCoordsToAlphaFormat(startupCoords);
		System.out.println(alphaCells);
		System.out.println(this);
		return alphaCells;
		}

		private boolean isValidLocation(int location, int startupSize, Alignment alignment) {
		int finalLocation = location + (alignment.getIncrement() * startupSize);
		if (alignment == HORIZONTAL) {
		return horizontalStartupFits(location, finalLocation);
		} else {
		return verticalStartupFits(finalLocation);
		}
		}

		private ArrayList<String> convertCoordsToAlphaFormat(int[] startupCoords) {
		ArrayList<String> alphaCells = new ArrayList<String>();
		for (int index : startupCoords) { // turn location into 'a0'-style startupCoords
		grid[index] = 1; // mark master grid position as ‘used'
		String alphaCoords = getAlphaCoordsFromIndex(index);
		alphaCells.add(alphaCoords);
		}
		System.out.println(alphaCells);
		System.out.println(this);
		return alphaCells;
		}

		void savePositionToGrid(int[] startupCoords) {
		for (int index : startupCoords) { // turn location into 'a0'-style startupCoords
		grid[index] = 1; // mark master grid position as ‘used'
		}
		}

		String getAlphaCoordsFromIndex(int index) {
		int row = calculateRowFromIndex(index); // get row value
		int column = index % GRID_LENGTH; // get numeric column value
		@@ -70,31 +89,24 @@ public class GameHelper {
		return letter + row;
		}

		boolean canPlaceStartup(int[] startupCoords) {
		for (int coord : startupCoords) {
		// check all potential positions
		if (grid[coord] == 0) {
		System.out.println("yes");
		System.out.println("startupCoords = " + Arrays.toString(startupCoords));
		} else {
		System.out.println("no");
		return false;
		boolean allPositionsAvailable(int[] startupCoords) {
		for (int coord : startupCoords) { // check all potential positions
		if (grid[coord] != 0) { // this co-ordinate already has an entry in the grid
		return false; // NO success
		}
		}
		return true;
		return true; // if the method got this far, there were no clashes, yay!
		}

		boolean horizontalStartupFits(int location, int startupSize) {
		int finalLocation = location + (HORIZONTAL.getIncrement() * startupSize);
		boolean horizontalStartupFits(int location, int finalLocation) {
		return calculateRowFromIndex(location) == calculateRowFromIndex(finalLocation); // check end is on same row as start
		}

		boolean verticalStartupFits(int location, int startupSize) {
		int finalLocation = location + (VERTICAL.getIncrement() * startupSize);
		boolean verticalStartupFits(int finalLocation) {
		return finalLocation < GRID_SIZE; // check end position doesn't go off the bottom of the grid
		}

		private Alignment calculateIncrement() {
		private Alignment getAlignment() {
		if (startupCount % 2 == 0) { // if EVEN Startup
		return HORIZONTAL; // place horizontally
		} else { // else ODD

src/test/java/ch6/GameHelperTest.java

+11 −12

Changes for src/test/java/ch6/GameHelperTest.java: 11 added lines, 12 removed lines.
Original line number	Diff line number	Diff line
		@@ -2,6 +2,8 @@ package ch6;

		import org.junit.jupiter.api.Test;

		import static ch6.GameHelper.Alignment.HORIZONTAL;
		import static ch6.GameHelper.Alignment.VERTICAL;
		import static org.junit.jupiter.api.Assertions.*;

		class GameHelperTest {
		@@ -45,7 +47,7 @@ class GameHelperTest {
		GameHelper gameHelper = new GameHelper();

		// expect
		assertFalse(gameHelper.horizontalStartupFits(26, 3));
		assertFalse(gameHelper.horizontalStartupFits(26, 26 + (HORIZONTAL.getIncrement() * 3)));
		}

		@Test
		@@ -54,7 +56,7 @@ class GameHelperTest {
		GameHelper gameHelper = new GameHelper();

		// expect
		assertTrue(gameHelper.verticalStartupFits(26, 3));
		assertTrue(gameHelper.verticalStartupFits(26 + (VERTICAL.getIncrement() * 3)));
		}

		@Test
		@@ -63,7 +65,7 @@ class GameHelperTest {
		GameHelper gameHelper = new GameHelper();

		// expect
		assertFalse(gameHelper.verticalStartupFits(47, 3));
		assertFalse(gameHelper.verticalStartupFits(47 + (VERTICAL.getIncrement() * 3)));
		}

		@Test
		@@ -73,7 +75,7 @@ class GameHelperTest {

		// when
		int[] startupCoords = new int[]{0, 1, 2};
		boolean success = gameHelper.canPlaceStartup(startupCoords);
		boolean success = gameHelper.allPositionsAvailable(startupCoords);

		// then
		assertTrue(success);
		@@ -86,7 +88,7 @@ class GameHelperTest {
		GameHelper gameHelper = new GameHelper();

		// when
		boolean success = gameHelper.canPlaceStartup(new int[]{0, 7, 14});
		boolean success = gameHelper.allPositionsAvailable(new int[]{0, 7, 14});

		// then
		assertTrue(success);
		@@ -96,13 +98,11 @@ class GameHelperTest {
		void shouldNotBeAbleToPlaceHorizontalIntoGridAtSameLocationAsExisting() {
		// given
		GameHelper gameHelper = new GameHelper();
		boolean setupSuccess = gameHelper.canPlaceStartup(new int[]{8, 9, 10}); // "B1"
		assertTrue(setupSuccess);
		gameHelper.savePositionToGrid(new int[]{8, 9, 10}); // "B1"
		System.out.println(gameHelper);

		// when
		int[] startupCoords = new int[3];
		boolean success = gameHelper.canPlaceStartup(new int[]{9, 10, 11}); // "C1" - horizontal
		boolean success = gameHelper.allPositionsAvailable(new int[]{9, 10, 11}); // "C1" - horizontal
		System.out.println(gameHelper);

		// then
		@@ -113,13 +113,12 @@ class GameHelperTest {
		void shouldNotBeAbleToPlaceVerticalIntoGridAtSameLocationAsExisting() {
		// given
		GameHelper gameHelper = new GameHelper();
		boolean setupSuccess = gameHelper.canPlaceStartup(new int[]{8, 9, 10}); // "B1"
		assertTrue(setupSuccess);
		gameHelper.savePositionToGrid(new int[]{8, 9, 10}); // "B1"
		System.out.println(gameHelper);

		// when
		int[] startupCoords = new int[]{1, 9, 16};
		boolean success = gameHelper.canPlaceStartup(startupCoords); // "A1" - vertical
		boolean success = gameHelper.allPositionsAvailable(startupCoords); // "A1" - vertical
		System.out.println(gameHelper);

		// then