Simplify and fix win32 Region.java

- Fix toString() missing closing brace (output was malformed)
- Use computeIfAbsent() in getRegionHandle() instead of manual
  containsKey/put/get
- Move RECT allocation inside isEmpty() lambda where it belongs
- Replace getBounds() block lambda with expression lambda
- Eliminate duplicate create/combine/delete patterns in
  OperationWithRectangle (3 methods -> combineWithRectInPixels)
  and OperationWithArray (2 methods -> combineWithPolyInPixels)
- Convert OperationWithRegion block lambdas to expression lambdas
- Remove redundant public modifiers on constructors of private
  inner classes OperationWithArray and OperationWithPoint

Author: HeikoKlare

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Region.java

@@ -288,9 +288,8 @@ public boolean equals (Object object) {
  */
 public Rectangle getBounds () {
 	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
-	return applyUsingAnyHandle(regionHandle -> {
-		return Win32DPIUtils.pixelToPoint(getBoundsInPixels(regionHandle.handle()), regionHandle.zoom());
-	});
+	return applyUsingAnyHandle(regionHandle ->
+		Win32DPIUtils.pixelToPoint(getBoundsInPixels(regionHandle.handle()), regionHandle.zoom()));
 }
 
 private Rectangle getBoundsInPixels(long handle) {
@@ -470,8 +469,8 @@ public boolean isDisposed() {
  */
 public boolean isEmpty () {
 	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
-	RECT rect = new RECT ();
 	return applyUsingAnyHandle(regionHandle -> {
+		RECT rect = new RECT();
 		int result = OS.GetRgnBox(regionHandle.handle(), rect);
 		if (result == OS.NULLREGION) return true;
 		return ((rect.right - rect.left) <= 0) || ((rect.bottom - rect.top) <= 0);
@@ -664,11 +663,7 @@ private static RegionHandle newRegionHandle(int zoom, List<Operation> operations
 }
 
 private RegionHandle getRegionHandle(int zoom) {
-	if (!zoomToHandle.containsKey(zoom)) {
-		RegionHandle regionHandle = newRegionHandle(zoom, operations);
-		zoomToHandle.put(zoom, regionHandle);
-	}
-	return zoomToHandle.get(zoom);
+	return zoomToHandle.computeIfAbsent(zoom, z -> newRegionHandle(z, operations));
 }
 
 Region copy() {
@@ -708,7 +703,7 @@ public static long win32_getHandle(Region region, int zoom) {
 @Override
 public String toString () {
 	if (isDisposed()) return "Region {*DISPOSED*}";
-	return "Region {" + zoomToHandle.entrySet().stream().map(entry -> entry.getValue() + "(zoom:" + entry.getKey() + ")").collect(Collectors.joining(","));
+	return "Region {" + zoomToHandle.entrySet().stream().map(entry -> entry.getValue() + "(zoom:" + entry.getKey() + ")").collect(Collectors.joining(",")) + "}";
 }
 
 private record RegionHandle(long handle, int zoom) {
@@ -760,45 +755,31 @@ void set(long handle, int zoom) {
 	@Override
 	void add(long handle, int zoom) {
 		Rectangle bounds = getScaledRectangle(zoom);
-		addInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height);
+		combineWithRectInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height, OS.RGN_OR);
 	}
 
 	@Override
 	void subtract(long handle, int zoom) {
 		Rectangle bounds = getScaledRectangle(zoom);
-		subtractInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height);
+		combineWithRectInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height, OS.RGN_DIFF);
 	}
 
 	@Override
 	void intersect(long handle, int zoom) {
 		Rectangle bounds = getScaledRectangle(zoom);
-		intersectInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height);
+		combineWithRectInPixels(handle, bounds.x, bounds.y, bounds.width, bounds.height, OS.RGN_AND);
 	}
 
 	@Override
 	void translate(long handle, int zoom) {
 		throw new UnsupportedOperationException();
 	}
 
-	private void addInPixels (long handle, int x, int y, int width, int height) {
-		if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
-		long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
-		OS.CombineRgn (handle, handle, rectRgn, OS.RGN_OR);
-		OS.DeleteObject (rectRgn);
-	}
-
-	private void subtractInPixels (long handle, int x, int y, int width, int height) {
+	private static void combineWithRectInPixels(long handle, int x, int y, int width, int height, int mode) {
 		if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
-		long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
-		OS.CombineRgn (handle, handle, rectRgn, OS.RGN_DIFF);
-		OS.DeleteObject (rectRgn);
-	}
-
-	private void intersectInPixels (long handle, int x, int y, int width, int height) {
-		if (width < 0 || height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
-		long rectRgn = OS.CreateRectRgn (x, y, x + width, y + height);
-		OS.CombineRgn (handle, handle, rectRgn, OS.RGN_AND);
-		OS.DeleteObject (rectRgn);
+		long rectRgn = OS.CreateRectRgn(x, y, x + width, y + height);
+		OS.CombineRgn(handle, handle, rectRgn, mode);
+		OS.DeleteObject(rectRgn);
 	}
 
 	private Rectangle getScaledRectangle(int zoom) {
@@ -810,7 +791,7 @@ private Rectangle getScaledRectangle(int zoom) {
 private static class OperationWithArray extends Operation {
 	private final int[] data;
 
-	public OperationWithArray(OperationStrategy operationStrategy, int[] data) {
+	OperationWithArray(OperationStrategy operationStrategy, int[] data) {
 		super(operationStrategy);
 		this.data = data;
 	}
@@ -822,14 +803,12 @@ void set(long handle, int zoom) {
 
 	@Override
 	void add(long handle, int zoom) {
-		int[] points = getScaledPoints(zoom);
-		addInPixels(handle, points);
+		combineWithPolyInPixels(handle, getScaledPoints(zoom), OS.RGN_OR);
 	}
 
 	@Override
 	void subtract(long handle, int zoom) {
-		int[] pointArray = getScaledPoints(zoom);
-		subtractInPixels(handle, pointArray);
+		combineWithPolyInPixels(handle, getScaledPoints(zoom), OS.RGN_DIFF);
 	}
 
 	@Override
@@ -842,16 +821,10 @@ void translate(long handle, int zoom) {
 		throw new UnsupportedOperationException();
 	}
 
-	private void addInPixels (long handle, int[] pointArray) {
-		long polyRgn = OS.CreatePolygonRgn(pointArray, pointArray.length / 2, OS.ALTERNATE);
-		OS.CombineRgn (handle, handle, polyRgn, OS.RGN_OR);
-		OS.DeleteObject (polyRgn);
-	}
-
-	private void subtractInPixels (long handle, int[] pointArray) {
+	private static void combineWithPolyInPixels(long handle, int[] pointArray, int mode) {
 		long polyRgn = OS.CreatePolygonRgn(pointArray, pointArray.length / 2, OS.ALTERNATE);
-		OS.CombineRgn (handle, handle, polyRgn, OS.RGN_DIFF);
-		OS.DeleteObject (polyRgn);
+		OS.CombineRgn(handle, handle, polyRgn, mode);
+		OS.DeleteObject(polyRgn);
 	}
 
 	private int[] getScaledPoints(int zoom) {
@@ -862,7 +835,7 @@ private int[] getScaledPoints(int zoom) {
 private static class OperationWithPoint extends Operation {
 	private final Point data;
 
-	public OperationWithPoint(OperationStrategy operationStrategy, Point data) {
+	OperationWithPoint(OperationStrategy operationStrategy, Point data) {
 		super(operationStrategy);
 		this.data = data;
 	}
@@ -910,23 +883,20 @@ void set(long handle, int zoom) {
 
 	@Override
 	void add(long handle, int zoom) {
-		applyUsingTemporaryHandle(zoom, operations, regionHandle -> {
-			return OS.CombineRgn (handle, handle, regionHandle.handle(), OS.RGN_OR);
-		});
+		applyUsingTemporaryHandle(zoom, operations, regionHandle ->
+			OS.CombineRgn(handle, handle, regionHandle.handle(), OS.RGN_OR));
 	}
 
 	@Override
 	void subtract(long handle, int zoom) {
-		applyUsingTemporaryHandle(zoom, operations, regionHandle -> {
-			return OS.CombineRgn (handle, handle, regionHandle.handle(), OS.RGN_DIFF);
-		});
+		applyUsingTemporaryHandle(zoom, operations, regionHandle ->
+			OS.CombineRgn(handle, handle, regionHandle.handle(), OS.RGN_DIFF));
 	}
 
 	@Override
 	void intersect(long handle, int zoom) {
-		applyUsingTemporaryHandle(zoom, operations, regionHandle -> {
-			return OS.CombineRgn (handle, handle, regionHandle.handle(), OS.RGN_AND);
-		});
+		applyUsingTemporaryHandle(zoom, operations, regionHandle ->
+			OS.CombineRgn(handle, handle, regionHandle.handle(), OS.RGN_AND));
 	}
 
 	@Override