[Java] Return NULL_VAL enum value for a unknown version rather than null so it can be used in a switch. PR #584.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/java/JavaGenerator.java

@@ -1722,19 +1722,24 @@ private static CharSequence generateStringNotPresentCondition(final int sinceVer
     }
 
     private static CharSequence generatePropertyNotPresentCondition(
-        final boolean inComposite, final CodecType codecType, final int sinceVersion, final String indent)
+        final boolean inComposite,
+        final CodecType codecType,
+        final Token propertyToken,
+        final String enumName,
+        final String indent)
     {
-        if (inComposite || codecType == ENCODER || 0 == sinceVersion)
+        if (inComposite || codecType == ENCODER || 0 == propertyToken.version())
         {
             return "";
         }
 
         return String.format(
             indent + "        if (parentMessage.actingVersion < %d)\n" +
             indent + "        {\n" +
-            indent + "            return null;\n" +
+            indent + "            return %s;\n" +
             indent + "        }\n\n",
-            sinceVersion);
+            propertyToken.version(),
+            enumName == null ? "null" : (enumName + ".NULL_VAL"));
     }
 
     private CharSequence generatePrimitiveArrayPropertyDecode(
@@ -2452,15 +2457,15 @@ private static void generateFieldMetaAttributeMethod(final StringBuilder sb, fin
 
     private CharSequence generateEnumDecoder(
         final boolean inComposite,
-        final Token signalToken,
+        final Token fieldToken,
         final String propertyName,
-        final Token token,
+        final Token typeToken,
         final String indent)
     {
-        final String enumName = formatClassName(token.applicableTypeName());
-        final Encoding encoding = token.encoding();
+        final String enumName = formatClassName(typeToken.applicableTypeName());
+        final Encoding encoding = typeToken.encoding();
 
-        if (token.isConstantEncoding())
+        if (typeToken.isConstantEncoding())
         {
             return String.format(
                 "\n" +
@@ -2470,7 +2475,7 @@ private CharSequence generateEnumDecoder(
                 indent + "    }\n\n",
                 enumName,
                 propertyName,
-                signalToken.encoding().constValue().toString());
+                fieldToken.encoding().constValue().toString());
         }
         else
         {
@@ -2483,9 +2488,9 @@ private CharSequence generateEnumDecoder(
                 indent + "    }\n\n",
                 enumName,
                 propertyName,
-                generatePropertyNotPresentCondition(inComposite, DECODER, signalToken.version(), indent),
+                generatePropertyNotPresentCondition(inComposite, DECODER, fieldToken, enumName, indent),
                 enumName,
-                generateGet(encoding.primitiveType(), "offset + " + token.offset(), byteOrderString(encoding)));
+                generateGet(encoding.primitiveType(), "offset + " + typeToken.offset(), byteOrderString(encoding)));
         }
     }
 
@@ -2541,7 +2546,7 @@ private CharSequence generateBitSetProperty(
             generateFlyweightPropertyJavadoc(indent + INDENT, propertyToken, bitSetName),
             bitSetName,
             propertyName,
-            generatePropertyNotPresentCondition(inComposite, codecType, propertyToken.version(), indent),
+            generatePropertyNotPresentCondition(inComposite, codecType, propertyToken, null, indent),
             propertyName,
             bitsetToken.offset(),
             propertyName));
@@ -2577,7 +2582,7 @@ private CharSequence generateCompositeProperty(
             generateFlyweightPropertyJavadoc(indent + INDENT, propertyToken, compositeName),
             compositeName,
             propertyName,
-            generatePropertyNotPresentCondition(inComposite, codecType, propertyToken.version(), indent),
+            generatePropertyNotPresentCondition(inComposite, codecType, propertyToken, null, indent),
             propertyName,
             compositeToken.offset(),
             propertyName));

sbe-tool/src/test/java/uk/co/real_logic/sbe/generation/java/SchemaExtensionTest.java

@@ -30,6 +30,7 @@
 
 import java.util.Map;
 
+import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.*;
 import static uk.co.real_logic.sbe.generation.java.ReflectionUtil.get;
 import static uk.co.real_logic.sbe.generation.java.ReflectionUtil.set;
@@ -87,7 +88,7 @@ public void testMessage1() throws Exception
             assertEquals(100, get(decoderVersion0, "tag1"));
             assertEquals(Integer.MIN_VALUE, get(decoderVersion0, "tag2"));
             assertNull(get(decoderVersion0, "tag3"));
-            assertNull(get(decoderVersion0, "tag4"));
+            assertThat(get(decoderVersion0, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion0, "tag5"));
 
             assertEquals(0, decoderVersion0.getClass().getMethod("tag1SinceVersion").invoke(null));
@@ -102,7 +103,7 @@ public void testMessage1() throws Exception
             assertEquals(100, get(decoderVersion1, "tag1"));
             assertEquals(200, get(decoderVersion1, "tag2"));
             assertNull(get(decoderVersion1, "tag3"));
-            assertNull(get(decoderVersion1, "tag4"));
+            assertThat(get(decoderVersion1, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion1, "tag5"));
         }
 
@@ -113,7 +114,7 @@ public void testMessage1() throws Exception
             final Object compositeDecoder2 = get(decoderVersion2, "tag3");
             assertNotNull(compositeDecoder2);
             assertEquals(300, get(compositeDecoder2, "value"));
-            assertNull(get(decoderVersion2, "tag4"));
+            assertThat(get(decoderVersion2, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion2, "tag5"));
         }
 
@@ -172,7 +173,7 @@ public void testMessage2() throws Exception
             assertEquals(100, get(decoderVersion0, "tag1"));
             assertEquals(Integer.MIN_VALUE, get(decoderVersion0, "tag2"));
             assertNull(get(decoderVersion0, "tag3"));
-            assertNull(get(decoderVersion0, "tag4"));
+            assertThat(get(decoderVersion0, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion0, "tag5"));
 
             assertEquals(0, decoderVersion0.getClass().getMethod("tag1SinceVersion").invoke(null));
@@ -189,7 +190,7 @@ public void testMessage2() throws Exception
             final Object compositeDecoder2 = get(decoderVersion1, "tag3");
             assertNotNull(compositeDecoder2);
             assertEquals(300, get(compositeDecoder2, "value"));
-            assertNull(get(decoderVersion1, "tag4"));
+            assertThat(get(decoderVersion1, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion1, "tag5"));
         }
 
@@ -200,7 +201,7 @@ public void testMessage2() throws Exception
             final Object compositeDecoder2 = get(decoderVersion2, "tag3");
             assertNotNull(compositeDecoder2);
             assertEquals(300, get(compositeDecoder2, "value"));
-            assertNull(get(decoderVersion2, "tag4"));
+            assertThat(get(decoderVersion2, "tag4").toString(), is("NULL_VAL"));
             assertNull(get(decoderVersion2, "tag5"));
         }
 
@@ -211,7 +212,7 @@ public void testMessage2() throws Exception
             final Object compositeDecoder3 = get(decoderVersion3, "tag3");
             assertNotNull(compositeDecoder3);
             assertEquals(300, get(compositeDecoder3, "value"));
-            assertNull(get(decoderVersion3, "tag4"));
+            assertThat(get(decoderVersion3, "tag4").toString(), is("NULL_VAL"));
             final Object setDecoder = get(decoderVersion3, "tag5");
             assertNotNull(setDecoder);
             assertEquals(false, get(setDecoder, "firstChoice"));