Merge pull request #10170 from abdallahsawan/BAEL-4161

The Value of 0xFF Number and Its Uses With & Operation in Java Ar…

java-numbers-4/src/main/java/com/baeldung/number_0xff/Number0xff.java

@@ -0,0 +1,20 @@
+package com.baeldung.number_0xff;
+
+public class Number0xff {
+
+    public static int getRedColor(int rgba) {
+        return rgba >> 24 & 0xff;
+    }
+
+    public static int getGreenColor(int rgba) {
+        return rgba >> 16 & 0xff;
+    }
+
+    public static int getBlueColor(int rgba) {
+        return rgba >> 8 & 0xff;
+    }
+
+    public static int getAlfa(int rgba) {
+        return rgba & 0xff;
+    }
+}

java-numbers-4/src/test/java/com/baeldung/number_0xff/Number0xffUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.number_0xff;
+
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+public class Number0xffUnitTest {
+
+    @Test
+    public void test0xFFAssignedToInteger() {
+        int x = 0xff;
+        int expectedValue = 255;
+        assertEquals(expectedValue, x);
+    }
+
+    @Test
+    public void test0xFFAssignedToByte() {
+        byte y = (byte) 0xff;
+        int expectedValue = -1;
+        assertEquals(expectedValue, y);
+    }
+
+    @Test
+    public void givenColor_whenGetRedColor_thenExtractRedColor() {
+        int rgba = 272214023;
+        int expectedValue = 16;
+        assertEquals(expectedValue, Number0xff.getRedColor(rgba));
+    }
+
+    @Test
+    public void givenColor_whenGetGreenColor_thenExtractGreenColor() {
+        int rgba = 272214023;
+        int expectedValue = 57;
+        assertEquals(expectedValue, Number0xff.getGreenColor(rgba));
+    }
+
+    @Test
+    public void givenColor_whenGetBlueColor_thenExtractBlueColor() {
+        int rgba = 272214023;
+        int expectedValue = 168;
+        assertEquals(expectedValue, Number0xff.getBlueColor(rgba));
+    }
+
+    @Test
+    public void givenColor_whenGetAlfa_thenExtractAlfa() {
+        int rgba = 272214023;
+        int expectedValue = 7;
+        assertEquals(expectedValue, Number0xff.getAlfa(rgba));
+    }
+}