[count-upper-lower] extract the impl. from the test methods

core-java-modules/core-java-string-operations-8/README.md

@@ -1,2 +1 @@
 ### Relevant Articles:
->>>>>>> be317465c ([count-upper-lower] count upper/lowercase letters)

core-java-modules/core-java-string-operations-8/src/test/java/com/baeldung/countupperandlowercasechars/CountUpperAndLowercaseCharsUnitTest.java

@@ -9,50 +9,26 @@ public class CountUpperAndLowercaseCharsUnitTest {
     private static final String MY_STRING = "Hi, Welcome to Baeldung! Let's count letters!";
 
     @Test
-    void whenIteratingCharArrayCompareAndCount_thenGetExpectedResult() {
+    void whenUsingCountByCharacterRange_thenGetExpectedResult() {
-        int upperCount = 0;
+        LetterCount result = LetterCount.countByCharacterRange(MY_STRING);
-        int lowerCount = 0;
-        for (char c : MY_STRING.toCharArray()) {
-            if (c >= 'A' && c <= 'Z') {
-                upperCount++;
-            }
-            if (c >= 'a' && c <= 'z') {
-                lowerCount++;
-            }
-        }
-        LetterCount result = new LetterCount(upperCount, lowerCount);
         assertEquals(4, result.getUppercaseCount());
         assertEquals(31, result.getLowercaseCount());
     }
 
     @Test
-    void whenUsingCharacterIsLowerOrUpperCase_thenGetExpectedResult() {
+    void whenUsingCountByCharacterIsLowerOrUpperCase_thenGetExpectedResult() {
-        int upperCount = 0;
+        LetterCount result = LetterCount.countByCharacterIsUpperLower(MY_STRING);
-        int lowerCount = 0;
-        for (char c : MY_STRING.toCharArray()) {
-            if (Character.isUpperCase(c)) {
-                upperCount++;
-            }
-            if (Character.isLowerCase(c)) {
-                lowerCount++;
-            }
-        }
-        LetterCount result = new LetterCount(upperCount, lowerCount);
         assertEquals(4, result.getUppercaseCount());
         assertEquals(31, result.getLowercaseCount());
     }
 
     @Test
-    void whenUsingStreamFilterAndCount_thenGetExpectedResult() {
+    void whenUsingCountByStreamApi_thenGetExpectedResult() {
-        LetterCount result = new LetterCount(
+        LetterCount result = LetterCount.countByStreamAPI(MY_STRING);
-            (int) MY_STRING.chars().filter(Character::isUpperCase).count(),
-            (int) MY_STRING.chars().filter(Character::isLowerCase).count()
-        );
         assertEquals(4, result.getUppercaseCount());
         assertEquals(31, result.getLowercaseCount());
     }
 
-
     @Test
     void whenUsingIsUpperCaseAndIsLowerCase_thenUnicodeCharactersCanBeChecked() {
         assertTrue(Character.isLowerCase('ä'));
@@ -64,11 +40,46 @@ class LetterCount {
     private int uppercaseCount;
     private int lowercaseCount;
 
-    public LetterCount(int uppercaseCount, int lowercaseCount) {
+    private LetterCount(int uppercaseCount, int lowercaseCount) {
         this.uppercaseCount = uppercaseCount;
         this.lowercaseCount = lowercaseCount;
     }
 
+    public static LetterCount countByCharacterRange(String input) {
+        int upperCount = 0;
+        int lowerCount = 0;
+        for (char c : input.toCharArray()) {
+            if (c >= 'A' && c <= 'Z') {
+                upperCount++;
+            }
+            if (c >= 'a' && c <= 'z') {
+                lowerCount++;
+            }
+        }
+        return new LetterCount(upperCount, lowerCount);
+    }
+
+    public static LetterCount countByCharacterIsUpperLower(String input) {
+        int upperCount = 0;
+        int lowerCount = 0;
+        for (char c : input.toCharArray()) {
+            if (Character.isUpperCase(c)) {
+                upperCount++;
+            }
+            if (Character.isLowerCase(c)) {
+                lowerCount++;
+            }
+        }
+        return new LetterCount(upperCount, lowerCount);
+    }
+
+    public static LetterCount countByStreamAPI(String input) {
+        return new LetterCount(
+            (int) input.chars().filter(Character::isUpperCase).count(),
+            (int) input.chars().filter(Character::isLowerCase).count()
+        );
+    }
+
     public int getUppercaseCount() {
         return uppercaseCount;
     }