1) Factory Method Pattern 2) applyMask 3) dynamic object construct

java/src/main/java/io/nayuki/qrcodegen/Msk1.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk1 {
+	public boolean operation(int y, int x, int msk) {
+		return (y % 2 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk2.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk2 {
+	public boolean operation(int y, int x, int msk) {
+		return (x % 3 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk3.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk3 {
+	public boolean operation(int y, int x, int msk) {
+		return ((x + y) % 3 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk4.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk4 {
+	public boolean operation(int y, int x, int msk) {
+		return ((x / 3 + y / 2) % 2 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk5.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk5 {
+	public boolean operation(int y, int x, int msk) {
+		return (x * y % 2 + x * y % 3 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk6.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk6 {
+	public boolean operation(int y, int x, int msk) {
+		return ((x * y % 2 + x * y % 3) % 2 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/Msk7.java

@@ -0,0 +1,7 @@
+package io.nayuki.qrcodegen;
+
+public class Msk7 {
+	public boolean operation(int y, int x, int msk) {
+		return (((x + y) % 2 + x * y % 3) % 2 == 0);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/MskCommandFactory.java

@@ -0,0 +1,46 @@
+package io.nayuki.qrcodegen;
+
+public class MskCommandFactory {
+	public static Command getCommand(int msk) {
+		Command theCommand = null;
+		
+		Msk0 msk0 = new Msk0();
+		Msk1 msk1 = new Msk1();
+		Msk2 msk2 = new Msk2();
+		Msk3 msk3 = new Msk3();
+		Msk4 msk4 = new Msk4();
+		Msk5 msk5 = new Msk5();
+		Msk6 msk6 = new Msk6();
+		Msk7 msk7 = new Msk7();
+		
+		switch (msk) {
+			case 0:
+				theCommand = new msk0Command(msk0);
+				break;
+			case 1: 
+				theCommand = new msk1Command(msk1);
+				break;
+			case 2: 
+				theCommand = new msk2Command(msk2);
+				break;
+			case 3:
+				theCommand = new msk3Command(msk3);
+				break;
+			case 4: 
+				theCommand = new msk4Command(msk4);
+				break;
+			case 5: 
+				theCommand = new msk5Command(msk5);
+				break;
+			case 6: 
+				theCommand = new msk6Command(msk6);
+				break;
+			case 7: 
+				theCommand = new msk7Command(msk7);
+				break;
+			default: 
+				throw new AssertionError();
+		}
+		return theCommand;
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/QrCode.java

@@ -542,37 +542,26 @@ public final class QrCode {
 	// The function modules must be marked and the codeword bits must be drawn
 	// before masking. Due to the arithmetic of XOR, calling applyMask() with
 	// the same mask value a second time will undo the mask. A final well-formed
-	// QR Code needs exactly one (not zero, two, etc.) mask applied.					Command pattern
+	// QR Code needs exactly one (not zero, two, etc.) mask applied.
 	private void applyMask(int msk) {
+
 		if (msk < 0 || msk > 7)
 			throw new IllegalArgumentException("Mask value out of range");
 		for (int y = 0; y < size; y++) {
 			for (int x = 0; x < size; x++) {
 				boolean invert;
-				Msk0 msk0 = new Msk0();
-				Command mskCommand = new msk0Command(msk0);
 
+				Command mskCommand = MskCommandFactory.getCommand(msk);
 				Button button = new Button(mskCommand);
 				invert = button.pressed(y, x, msk);
-				/*
+
-				switch (msk) {
-				case 0:  invert = (x + y) % 2 == 0;                    break;
-				case 1:  invert = y % 2 == 0;                          break;
-				case 2:  invert = x % 3 == 0;                          break;
-				case 3:  invert = (x + y) % 3 == 0;                    break;
-				case 4:  invert = (x / 3 + y / 2) % 2 == 0;            break;
-				case 5:  invert = x * y % 2 + x * y % 3 == 0;          break;
-				case 6:  invert = (x * y % 2 + x * y % 3) % 2 == 0;    break;
-				case 7:  invert = ((x + y) % 2 + x * y % 3) % 2 == 0;  break;
-				default:  throw new AssertionError();
-				}
-				*/
 				modules[y][x] ^= invert & !isFunction[y][x];
 			}
 		}
 	}
 	
 
+
 	// A messy helper function for the constructor. This QR Code must be in an unmasked state when this
 	// method is called. The given argument is the requested mask, which is -1 for auto or 0 to 7 for fixed.
 	// This method applies and returns the actual mask chosen, from 0 to 7.
@@ -619,21 +608,6 @@ public final class QrCode {
 		return result;
 	}
 	
-	private int twobytwoHavingSameColor(boolean[][] modules) {
-		int result = 0;
-		// 2*2 blocks of modules having same color
-		for (int y = 0; y < size - 1; y++) {
-			for (int x = 0; x < size - 1; x++) {
-				boolean color = modules[y][x];
-				if (  color == modules[y][x + 1] &&
-						color == modules[y + 1][x] &&
-						color == modules[y + 1][x + 1])
-					result += PENALTY_N2;
-			}
-		}
-		return result;
-	}
-	
 	// Calculates and returns the penalty score based on state of this QR Code's current modules.
 	// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
 	private int getPenaltyScore() {
@@ -679,6 +653,21 @@ public final class QrCode {
 		return result;
 	}
 
+	private int twobytwoHavingSameColor(boolean[][] modules) {
+		int result = 0;
+		// 2*2 blocks of modules having same color. 
+		for (int y = 0; y < size - 1; y++) {
+			for (int x = 0; x < size - 1; x++) {
+				boolean color = modules[y][x];
+				if (  color == modules[y][x + 1] &&
+						color == modules[y + 1][x] &&
+						color == modules[y + 1][x + 1])
+					result += PENALTY_N2;
+			}
+		}
+		return result;
+	}
+
 	/*---- Private helper functions ----*/
 
 	// Returns an ascending list of positions of alignment patterns for this version number.

java/src/main/java/io/nayuki/qrcodegen/msk1Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk1Command implements Command {
+	private Msk1 theMsk1;
+	
+	public msk1Command(Msk1 theMsk1) {
+		this.theMsk1 = theMsk1;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk1.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk2Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk2Command implements Command {
+	private Msk2 theMsk2;
+	
+	public msk2Command(Msk2 theMsk2) {
+		this.theMsk2 = theMsk2;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk2.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk3Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk3Command implements Command {
+	private Msk3 theMsk3;
+	
+	public msk3Command(Msk3 theMsk3) {
+		this.theMsk3 = theMsk3;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk3.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk4Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk4Command implements Command {
+	private Msk4 theMsk4;
+	
+	public msk4Command(Msk4 theMsk4) {
+		this.theMsk4 = theMsk4;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk4.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk5Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk5Command implements Command {
+	private Msk5 theMsk5;
+	
+	public msk5Command(Msk5 theMsk5) {
+		this.theMsk5 = theMsk5;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk5.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk6Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk6Command implements Command {
+	private Msk6 theMsk6;
+	
+	public msk6Command(Msk6 theMsk6) {
+		this.theMsk6 = theMsk6;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk6.operation(y, x, msk);
+	}
+}

java/src/main/java/io/nayuki/qrcodegen/msk7Command.java

@@ -0,0 +1,13 @@
+package io.nayuki.qrcodegen;
+
+public class msk7Command implements Command {
+	private Msk7 theMsk7;
+	
+	public msk7Command(Msk7 theMsk7) {
+		this.theMsk7 = theMsk7;
+	}
+	
+	public boolean excute(int y, int x, int msk) {
+		return theMsk7.operation(y, x, msk);
+	}
+}