Initial commit

common/unsafe/src/main/java/org/apache/spark/sql/catalyst/util/CollationAwareUTF8String.java

@@ -342,7 +342,7 @@ public static UTF8String toUpperCase(final UTF8String target) {
     return UTF8String.fromString(toUpperCase(target.toString()));
   }
 
-  public static String toUpperCase(final String target) {
+  private static String toUpperCase(final String target) {
     return UCharacter.toUpperCase(target);
   }
 
@@ -356,7 +356,7 @@ public static UTF8String toUpperCase(final UTF8String target, final int collatio
     return UTF8String.fromString(toUpperCase(target.toString(), collationId));
   }
 
-  public static String toUpperCase(final String target, final int collationId) {
+  private static String toUpperCase(final String target, final int collationId) {
     ULocale locale = CollationFactory.fetchCollation(collationId)
       .collator.getLocale(ULocale.ACTUAL_LOCALE);
     return UCharacter.toUpperCase(locale, target);
@@ -371,7 +371,7 @@ public static String toUpperCase(final String target, final int collationId) {
   public static UTF8String toLowerCase(final UTF8String target) {
     return UTF8String.fromString(toLowerCase(target.toString()));
   }
-  public static String toLowerCase(final String target) {
+  private static String toLowerCase(final String target) {
     return UCharacter.toLowerCase(target);
   }
 
@@ -384,7 +384,7 @@ public static String toLowerCase(final String target) {
   public static UTF8String toLowerCase(final UTF8String target, final int collationId) {
     return UTF8String.fromString(toLowerCase(target.toString(), collationId));
   }
-  public static String toLowerCase(final String target, final int collationId) {
+  private static String toLowerCase(final String target, final int collationId) {
     ULocale locale = CollationFactory.fetchCollation(collationId)
       .collator.getLocale(ULocale.ACTUAL_LOCALE);
     return UCharacter.toLowerCase(locale, target);
@@ -424,7 +424,11 @@ else if (codePoint == 0x03C2) {
    * @param target The target string to convert to lowercase.
    * @return The string converted to lowercase in a context-unaware manner.
    */
-  public static String lowerCaseCodePoints(final String target) {
+  public static UTF8String lowerCaseCodePoints(final UTF8String target) {
+    return UTF8String.fromString(lowerCaseCodePoints(target.toString()));
+  }
+
+  private static String lowerCaseCodePoints(final String target) {
     StringBuilder sb = new StringBuilder();
     for (int i = 0; i < target.length(); ++i) {
       lowercaseCodePoint(target.codePointAt(i), sb);
@@ -439,7 +443,7 @@ public static UTF8String toTitleCase(final UTF8String target) {
     return UTF8String.fromString(toTitleCase(target.toString()));
   }
 
-  public static String toTitleCase(final String target) {
+  private static String toTitleCase(final String target) {
     return UCharacter.toTitleCase(target, BreakIterator.getWordInstance());
   }
 
@@ -450,7 +454,7 @@ public static UTF8String toTitleCase(final UTF8String target, final int collatio
     return UTF8String.fromString(toTitleCase(target.toString(), collationId));
   }
 
-  public static String toTitleCase(final String target, final int collationId) {
+  private static String toTitleCase(final String target, final int collationId) {
     ULocale locale = CollationFactory.fetchCollation(collationId)
       .collator.getLocale(ULocale.ACTUAL_LOCALE);
     return UCharacter.toTitleCase(locale, target, BreakIterator.getWordInstance(locale));

common/unsafe/src/main/java/org/apache/spark/sql/catalyst/util/CollationFactory.java

@@ -414,7 +414,7 @@ protected Collation buildCollation() {
             null,
             CollationAwareUTF8String::compareLowerCase,
             "1.0",
-            s -> (long) CollationAwareUTF8String.lowerCaseCodePoints(s.toString()).hashCode(),
+            s -> (long) CollationAwareUTF8String.lowerCaseCodePoints(s).hashCode(),
             /* supportsBinaryEquality = */ false,
             /* supportsBinaryOrdering = */ false,
             /* supportsLowercaseEquality = */ true);

common/unsafe/src/test/java/org/apache/spark/unsafe/types/CollationSupportSuite.java

@@ -135,7 +135,7 @@ private void assertLowerCaseCodePoints(UTF8String target, UTF8String expected,
       Boolean useCodePoints) {
     if (useCodePoints) {
       assertEquals(expected.toString(),
-        CollationAwareUTF8String.lowerCaseCodePoints(target.toString()));
+        CollationAwareUTF8String.lowerCaseCodePoints(target));
     } else {
       assertEquals(expected, target.toLowerCase());
     }