[Ch6] GameHelper: refactored out a while loop and broke into a bunch of methods. Still not there. (080de396) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch6/GameHelper.java

+77 −24

Changes for src/main/java/ch6/GameHelper.java: 77 added lines, 24 removed lines.
Original line number	Diff line number	Diff line
		package ch6;

		import java.util.ArrayList;
		import java.util.Arrays;
		import java.util.Random;
		import java.util.Scanner;

		import static ch6.GameHelper.Alignment.HORIZONTAL;
		import static ch6.GameHelper.Alignment.VERTICAL;

		public class GameHelper {
		private static final String ALPHABET = "abcdefg";
		private static final int GRID_LENGTH = 7;
		@@ -29,56 +33,90 @@ public class GameHelper {
		boolean success = false; // flag = found a good location ?

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

		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
		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
		if (alignment == HORIZONTAL) {
		success = horizontalStartupFits(location, startupSize);
		} else{
		success = verticalStartupFits(location, startupSize);

		}

		if (success) {
		success = bruteForcePlace(startupSize, startupCoords, alignment.getIncrement(), location);
		}
		} // end while
		System.out.println(this);

		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);
		String alphaCoords = getAlphaCoordsFromIndex(index);
		alphaCells.add(alphaCoords);
		}
		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);
		String getAlphaCoordsFromIndex(int index) {
		int row = calculateRowFromIndex(index); // get row value
		int column = index % GRID_LENGTH; // get numeric column value

		String letter = ALPHABET.substring(column, column + 1); // convert column index to letter
		String alphaCoords = letter + row;
		return alphaCoords;
		}

		private boolean bruteForcePlace(int startupSize, int[] startupCoords, int increment, int location) {
		System.out.println("startupSize = " + startupSize + ", startupCoords = " + Arrays.toString(startupCoords) + ", increment = " + increment + ", location = " + location);
		int k = 0;
		for (int j = location; k < startupSize; j += increment) {
		System.out.println("check it's available. k=" + k + ", startupSize:" + startupSize);
		// check all potential positions
		if (grid[j] == 0) {
		System.out.println("yes");
		startupCoords[k++] = j; // save location
		System.out.println("startupCoords = " + Arrays.toString(startupCoords));
		} else {
		System.out.println("no");
		return false;
		}
		}
		return true;
		}

		private int calculateIncrement() {
		boolean horizontalStartupFits(int location, int startupSize) {
		int finalLocation = location + (HORIZONTAL.getIncrement() * startupSize);
		if (calculateRowFromIndex(location) != calculateRowFromIndex(finalLocation)) { // end position is on a different row to start position
		System.out.println("location = " + location + ", startupSize = " + startupSize);
		return false;
		}
		return true;
		}

		boolean verticalStartupFits(int location, int startupSize) {
		int finalLocation = location + (VERTICAL.getIncrement() * startupSize);
		if (finalLocation > GRID_SIZE) { // end position is off the bottom
		System.out.println("location = " + location + ", startupSize = " + startupSize);
		return false;
		}
		return true;
		}

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

		private int calculateRowFromIndex(int index) {
		return index / GRID_LENGTH;
		}

		@Override
		public String toString() {
		StringBuilder str = new StringBuilder();
		@@ -90,4 +128,19 @@ public class GameHelper {
		}
		return str.toString();
		}

		enum Alignment {
		HORIZONTAL(1), VERTICAL(GRID_LENGTH);

		private final int increment;

		Alignment(int increment) {
		this.increment = increment;
		}

		public int getIncrement() {
		return increment;
		}
		}
		}

src/test/java/ch6/GameHelperTest.java

+44 −1

Changes for src/test/java/ch6/GameHelperTest.java: 44 added lines, 1 removed line.
Original line number	Diff line number	Diff line
		@@ -2,7 +2,7 @@ package ch6;

		import org.junit.jupiter.api.Test;

		import static org.junit.jupiter.api.Assertions.assertEquals;
		import static org.junit.jupiter.api.Assertions.*;

		class GameHelperTest {
		@Test
		@@ -28,4 +28,47 @@ class GameHelperTest {
		// expect
		assertEquals('g', columnIndex + 97);
		}

		@Test
		void shouldConvertIndexLocationToAlphaCoords() {
		// given
		GameHelper gameHelper = new GameHelper();

		// expect
		assertEquals("f3", gameHelper.getAlphaCoordsFromIndex(26));
		assertEquals("f6", gameHelper.getAlphaCoordsFromIndex(47));
		}

		@Test
		void shouldNotLetStartupGoOverRightEdge() {
		// given
		GameHelper gameHelper = new GameHelper();

		// expect
		assertFalse(gameHelper.horizontalStartupFits(26, 3));
		}

		@Test
		void shouldAllowVerticalStartups() {
		// given
		GameHelper gameHelper = new GameHelper();

		// expect
		assertTrue(gameHelper.verticalStartupFits(26, 3));
		}

		@Test
		void shouldNotLetStartupGoOverBottom() {
		// given
		GameHelper gameHelper = new GameHelper();

		// expect
		assertFalse(gameHelper.verticalStartupFits(47, 3));
		}

		@Test
		void shouldTurnIndexIntoAlphaCoords() {
		GameHelper gameHelper = new GameHelper();
		assertEquals("f3", gameHelper.getAlphaCoordsFromIndex(26));
		}
		}
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