Use singleton pattern

Author: roozbehp

unicodetools/src/main/java/org/unicode/text/UCD/GenerateConfusables.java

@@ -592,7 +592,7 @@ static void generateDecompFile() throws IOException {
             out.println("");
             for (final UnicodeSetIterator usi = new UnicodeSetIterator(s); usi.next(); ) {
                 final String source = usi.getString();
-                final String target = getModifiedNFKD(source);
+                final String target = ModifiedNFKD.normalize(source);
                 writeSourceTargetLine(out, source, "N", target, value, ARROW);
             }
             // bf.showSetNames(out, s);
@@ -724,12 +724,12 @@ private static UnicodeSet getSkipNFKD() {
                 }
                 final String source = UTF16.valueOf(cp);
                 final String mapped = NFKD.normalize(cp);
-                String kmapped = getModifiedNFKD(source);
+                String kmapped = ModifiedNFKD.normalize(source);
                 if (!kmapped.equals(source) && !kmapped.equals(nfc)) {
                     if (kmapped.startsWith(" ") || kmapped.startsWith("\u0640")) {
                         if (DEBUG) System.out.println("?? " + DEFAULT_UCD.getCodeAndName(cp));
                         if (DEBUG) System.out.println("\t" + DEFAULT_UCD.getCodeAndName(kmapped));
-                        kmapped = getModifiedNFKD(source); // for debugging
+                        kmapped = ModifiedNFKD.normalize(source); // for debugging
                     }
                     nfkdMap.put(cp, kmapped);
                 }
@@ -2637,24 +2637,15 @@ private static String getReasonFromFilename(String type) {
         return type.substring(dash + 1, period);
     }
 
-    private static Normalizer modNFKD;
-
-    static String getModifiedNFKD(String cf) {
-        if (modNFKD == null) {
-            modNFKD = new Normalizer(UCD_Types.NFKD, Default.ucdVersion());
-            modNFKD.setSpacingSubstitute();
-        }
-        return modNFKD.normalize(cf);
-    }
-
-    private static Normalizer modNFKC;
-
-    static String getModifiedNFKC(String cf) {
-        if (modNFKC == null) {
-            modNFKC = new Normalizer(UCD_Types.NFKC, Default.ucdVersion());
-            modNFKC.setSpacingSubstitute();
+    private static final class ModifiedNFKD {
+        private static Normalizer INSTANCE;
+        static String normalize(String cf) {
+            if (INSTANCE == null) {
+                INSTANCE = new Normalizer(UCD_Types.NFKD, Default.ucdVersion());
+                INSTANCE.setSpacingSubstitute();
+            }
+            return ModifiedNFKD.INSTANCE.normalize(cf);
         }
-        return modNFKC.normalize(cf);
     }
 
     static PrintWriter openAndWriteHeader(String dir, String filename, String title)

unicodetools/src/main/java/org/unicode/text/UCD/IdentifierInfo.java

@@ -138,6 +138,17 @@ public static void main(String[] args) throws IOException {
         info.printIDNStuff();
     }
 
+    private static final class ModifiedNFKC {
+        private static Normalizer INSTANCE;
+        static String normalize(String cf) {
+            if (INSTANCE == null) {
+                INSTANCE = new Normalizer(UCD_Types.NFKC, Default.ucdVersion());
+                INSTANCE.setSpacingSubstitute();
+            }
+            return ModifiedNFKC.INSTANCE.normalize(cf);
+        }
+    }
+
     private IdentifierInfo() throws IOException {
         isCaseFolded = new UnicodeSet();
         for (int cp = 0; cp <= 0x10FFFF; ++cp) {
@@ -189,9 +200,9 @@ private IdentifierInfo() throws IOException {
         // the output set
         for (final UnicodeSetIterator usi = new UnicodeSetIterator(remainingInputSet1);
                 usi.next(); ) {
-            final String nss = GenerateConfusables.getModifiedNFKC(usi.getString());
+            final String nss = ModifiedNFKC.normalize(usi.getString());
             final String cf = DEFAULT_UCD.getCase(nss, UCD_Types.FULL, UCD_Types.FOLD);
-            final String cf2 = GenerateConfusables.getModifiedNFKC(cf);
+            final String cf2 = ModifiedNFKC.normalize(cf);
             if (remainingOutputSet.containsAll(cf2)) {
                 remainingInputSet.add(usi.codepoint);
             } else {
@@ -203,7 +214,7 @@ private IdentifierInfo() throws IOException {
         for (final UnicodeSetIterator usi = new UnicodeSetIterator(remainingInputSet);
                 usi.next(); ) {
             final String ss = usi.getString();
-            final String nss = GenerateConfusables.getModifiedNFKC(ss);
+            final String nss = ModifiedNFKC.normalize(ss);
             final String cf = DEFAULT_UCD.getCase(ss, UCD_Types.FULL, UCD_Types.FOLD);
             if (DEBUG && (usi.codepoint == 0x2126 || usi.codepoint == 0x212B)) {
                 System.out.println("check");