ICU-10268 Create private ImmutableNumberFormat wrapper so that developers don't have...

X-SVN-Rev: 34794

diff --git a/icu4j/main/classes/core/src/com/ibm/icu/text/MeasureFormat.java b/icu4j/main/classes/core/src/com/ibm/icu/text/MeasureFormat.java
index 0a7c3e20a2eaffe5fd7d9b7feadd29ca2db50c8c..39cfd1c52a0cce68b5c452e259f0aa5b1dca63e8 100644 (file)
--- a/icu4j/main/classes/core/src/com/ibm/icu/text/MeasureFormat.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/text/MeasureFormat.java
@@ -95,9 +95,7 @@ public class MeasureFormat extends UFormat {
     // Generated by serialver from JDK 1.4.1_01
     static final long serialVersionUID = -7182021401701778240L;
     
-    // NumberFormat is known to lack thread-safety, all access to this
-    // field must be synchronized.
-    private final transient NumberFormat numberFormat;
+    private final transient ImmutableNumberFormat numberFormat;
     
     private final transient FormatWidth length;
     
@@ -190,7 +188,8 @@ public class MeasureFormat extends UFormat {
             unitToStyleToCountToFormat = loadLocaleData(locale, rules);
             localeToUnitToStyleToCountToFormat.put(locale, unitToStyleToCountToFormat);
         }
-        return new MeasureFormat(locale, width, format, rules, unitToStyleToCountToFormat);
+        return new MeasureFormat(
+                locale, width, new ImmutableNumberFormat(format), rules, unitToStyleToCountToFormat);
     }
     
     /**
@@ -421,9 +420,7 @@ public class MeasureFormat extends UFormat {
      * @provisional
      */
     public NumberFormat getNumberFormat() {
-        synchronized (numberFormat) {
-            return (NumberFormat) numberFormat.clone();
-        }
+        return numberFormat.get();
     }
 
     /**
@@ -456,7 +453,7 @@ public class MeasureFormat extends UFormat {
         return new MeasureFormat(
                 getLocale(),
                 this.length,
-                (NumberFormat) format.clone(),
+                new ImmutableNumberFormat(format),
                 this.rules,
                 this.unitToStyleToCountToFormat);
     }
@@ -464,7 +461,7 @@ public class MeasureFormat extends UFormat {
     private MeasureFormat(
             ULocale locale,
             FormatWidth width,
-            NumberFormat format,
+            ImmutableNumberFormat format,
             PluralRules rules,
             Map<MeasureUnit, EnumMap<FormatWidth, Map<String, PatternData>>> unitToStyleToCountToFormat) {
         setLocale(locale, locale);
@@ -588,22 +585,17 @@ public class MeasureFormat extends UFormat {
 
     }
     
-    private static boolean objEquals(Object lhs, Object rhs) {
-        return lhs == null ? rhs == null : lhs.equals(rhs);
-        
-    }
-    
     Object toTimeUnitProxy() {
-        return new MeasureProxy(getLocale(), length, numberFormat, TIME_UNIT_FORMAT);
+        return new MeasureProxy(getLocale(), length, numberFormat.get(), TIME_UNIT_FORMAT);
     }
     
     Object toCurrencyProxy() {
-        return new MeasureProxy(getLocale(), length, numberFormat, CURRENCY_FORMAT);
+        return new MeasureProxy(getLocale(), length, numberFormat.get(), CURRENCY_FORMAT);
     }
     
     private Object writeReplace() throws ObjectStreamException {
         return new MeasureProxy(
-                getLocale(), length, numberFormat, MEASURE_FORMAT);
+                getLocale(), length, numberFormat.get(), MEASURE_FORMAT);
     }
     
     static class MeasureProxy implements Externalizable {
@@ -712,4 +704,22 @@ public class MeasureFormat extends UFormat {
             throw new IllegalStateException("Unable to serialize Format Width " + fw);
         }
     }
+    
+    // Wrapper around NumberFormat that provides immutability and thread-safety.
+    private static final class ImmutableNumberFormat {
+        private NumberFormat nf;
+        
+        public ImmutableNumberFormat(NumberFormat nf) {
+            this.nf = (NumberFormat) nf.clone();
+        }
+        
+        public synchronized NumberFormat get() {
+            return (NumberFormat) nf.clone();
+        }
+        
+        public synchronized StringBuffer format(
+                Number n, StringBuffer buffer, FieldPosition pos) {
+            return nf.format(n, buffer, pos);
+        }
+    }
 }