[CODEC-249] Fix Incorrect transform of CH digraph according Metaphone basic rules (#423)

* [CODEC-249] Fix Incorrect transform of CH digraph according Metaphone basic rules

* [CODEC-249] Add. test for Metaphone CH character translation with max code length of 5

* Remove blank lines.

---------

Co-authored-by: Gary Gregory <garydgregory@users.noreply.github.com>

Author: Shalujha0907

src/main/java/org/apache/commons/codec/language/Metaphone.java

@@ -246,23 +246,19 @@ public String metaphone(final String txt) {
                     if (isPreviousChar(local, n, 'S') && !isLastChar(wdsz, n) && FRONTV.indexOf(local.charAt(n + 1)) >= 0) {
                         break;
                     }
-                    if (regionMatch(local, n, "CIA")) { // "CIA" -> X
+                    if (isPreviousChar(local, n, 'S') && isNextChar(local, n, 'H')) { // SCH->sk
+                        code.append('K');
+                        break;
+                    }
+                    if (regionMatch(local, n, "CIA") || isNextChar(local, n, 'H')) { // "CIA" -> X or CH -> X
                         code.append('X');
                         break;
                     }
                     if (!isLastChar(wdsz, n) && FRONTV.indexOf(local.charAt(n + 1)) >= 0) {
                         code.append('S');
                         break; // CI,CE,CY -> S
                     }
-                    if (isPreviousChar(local, n, 'S') && isNextChar(local, n, 'H')) { // SCH->sk
-                        code.append('K');
-                        break;
-                    }
-                    if (!isNextChar(local, n, 'H') || n == 0 && wdsz >= 3 && isVowel(local, 2)) { // CH consonant -> K consonant
-                        code.append('K');
-                    } else {
-                        code.append('X'); // CHvowel -> X
-                    }
+                    code.append('K'); // default C -> K
                     break;
                 case 'D':
                     if (!isLastChar(wdsz, n + 1) && isNextChar(local, n, 'G') && FRONTV.indexOf(local.charAt(n + 2)) >= 0) { // DGE DGI DGY -> J

src/test/java/org/apache/commons/codec/language/MetaphoneTest.java

@@ -272,11 +272,28 @@ void testTIOAndTIAToX() {
 
     @Test
     void testTranslateOfSCHAndCH() {
+        assertEquals("SNS", getStringEncoder().metaphone("SCIENCE"));
+        assertEquals("SN", getStringEncoder().metaphone("SCENE"));
+        assertEquals("S", getStringEncoder().metaphone("SCY"));
         assertEquals("SKTL", getStringEncoder().metaphone("SCHEDULE"));
         assertEquals("SKMT", getStringEncoder().metaphone("SCHEMATIC"));
-
-        assertEquals("KRKT", getStringEncoder().metaphone("CHARACTER"));
+        assertEquals("TSKR", getStringEncoder().metaphone("DISCHARGE"));
+        assertEquals("EX", getStringEncoder().metaphone("ECHO"));
         assertEquals("TX", getStringEncoder().metaphone("TEACH"));
+        assertEquals("XR", getStringEncoder().metaphone("CHERI"));
+        assertEquals("XP", getStringEncoder().metaphone("CHIP"));
+        assertEquals("XRST", getStringEncoder().metaphone("CHRIST"));
+        assertEquals("X", getStringEncoder().metaphone("CIAO"));
+        assertEquals("ST", getStringEncoder().metaphone("CITY"));
+        assertEquals("KT", getStringEncoder().metaphone("CAT"));
+
+    }
+
+    @Test
+    void testTranslateOfCHCharacterWithMaxCodeLenFive() {
+        final Metaphone metaphone = new Metaphone();
+        metaphone.setMaxCodeLen(5);
+        assertEquals("XRKTR", metaphone.metaphone("CHARACTER"));
     }
 
     @Test