Updated the code to throw better exceptions on bad arguments

git-svn-id: https://android-motion-detection.googlecode.com/svn/trunk@17 996b93ed-3e4d-4b21-1044-74bd19560d1d

src/com/jwetherell/motion_detection/detection/Comparer.java

@@ -31,8 +31,10 @@ public void setDebugMode(int m) {
 
 	// compare two images.
 	public Comparison compare(State s1, State s2) {
-		if (s1==null || s2==null) return null;
-		if (s1.getWidth()!=s2.getWidth() || s1.getHeight()!=s2.getHeight()) return null;
+		if (s1==null || s2==null) 
+			throw new NullPointerException();
+		if (s1.getWidth()!=s2.getWidth() || s1.getHeight()!=s2.getHeight()) 
+			throw new IllegalArgumentException();
 
 		// number of boxes
 		int xBoxes = comparex;

src/com/jwetherell/motion_detection/detection/Comparison.java

@@ -18,7 +18,7 @@ public class Comparison {
 	private boolean different = false;
 
 	public Comparison(State s1, State s2, int[][] variance, boolean different) {
-		if (variance==null) throw new NullPointerException();
+		if (variance==null || s1==null || s2==null) throw new NullPointerException();
 
 		this.s1 = s1;
 		this.s2 = s2;
@@ -30,6 +30,8 @@ public Comparison(State s1, State s2, int[][] variance, boolean different) {
 	}
 
 	public void getChangeIndicator(int[] data, int width, int height, Comparer comparer) {
+		if (data==null || comparer==null) throw new NullPointerException();
+
 		int xBoxes = comparer.getCompareX();
 		if (xBoxes > s1.getWidth()) xBoxes = s1.getWidth();
 		int yBoxes = comparer.getCompareY();

src/com/jwetherell/motion_detection/detection/MotionDetection.java

@@ -30,7 +30,9 @@ public static int[] getPrevious() {
 	}
 
 	protected static boolean isDifferentComparingState(int[] first, int width, int height) {
-		if (first==null || mPrevious==null) return false;
+		if (first==null) throw new NullPointerException();
+
+		if (mPrevious==null) return false;
 		if (first.length != mPrevious.length) return true;
 		if (mPreviousWidth != width || mPreviousHeight != height) return true;
 
@@ -56,7 +58,9 @@ protected static boolean isDifferentComparingState(int[] first, int width, int h
 	}
 
 	protected static boolean isDifferentComparingLuminescence(int[] first, int width, int height) {
-		if (first==null || mPrevious==null) return false;
+		if (first==null) throw new NullPointerException();
+
+		if (mPrevious==null) return false;
 		if (first.length != mPrevious.length) return true;
 		if (mPreviousWidth != width || mPreviousHeight != height) return true;
 
@@ -96,7 +100,9 @@ protected static boolean isDifferentComparingLuminescence(int[] first, int width
 	}
 
 	protected static boolean isDifferentComparingRGB(int[] first, int width, int height) {
-		if (first==null || mPrevious==null) return false;
+		if (first==null) throw new NullPointerException();
+
+		if (mPrevious==null) return false;
 		if (first.length != mPrevious.length) return true;
 		if (mPreviousWidth != width || mPreviousHeight != height) return true;
 
@@ -136,7 +142,8 @@ protected static boolean isDifferentComparingRGB(int[] first, int width, int hei
 	}
 
 	public static boolean detect(int[] rgb, int width, int height) {
-		if (rgb==null) return false;
+		if (rgb==null) throw new NullPointerException();
+
 		int[] original = rgb.clone();
 
 		// Create the "mPrevious" picture, the one that will be used to check the next frame against.
@@ -163,4 +170,4 @@ public static boolean detect(int[] rgb, int width, int height) {
 
 		return motionDetected;
 	}
-}
+}

src/com/jwetherell/motion_detection/detection/State.java

@@ -33,7 +33,7 @@ public State(int[] data, int width, int height) {
 		average = 0;
 		for (int y = 0, xy=0; y < this.height; y++) {
 			for (int x = 0; x < this.width; x++, xy++) {
-				average += data[xy];;
+				average += data[xy];
 			}
 		}
 		average = (average / (this.width * this.height));