[Java] Extend arbitrary varData encodings.

We now explore more of the "schema space", as we generate lengths of
different encodings.

It surfaces an issue, reported in aeron-io#955, which was fixed in another
outstanding PR's commit: 3885a63.

Author: ZachBray

sbe-tool/src/propertyTest/java/uk/co/real_logic/sbe/properties/arbitraries/SbeArbitraries.java

@@ -150,10 +150,18 @@ private static Arbitrary<EnumTypeSchema> enumTypeSchema()
     private static Arbitrary<SetSchema> setTypeSchema()
     {
         return Arbitraries.oneOf(
-            Arbitraries.integers().between(0, 7).set().map(choices -> new SetSchema("uint8", choices)),
-            Arbitraries.integers().between(0, 15).set().map(choices -> new SetSchema("uint16", choices)),
-            Arbitraries.integers().between(0, 31).set().map(choices -> new SetSchema("uint32", choices)),
-            Arbitraries.integers().between(0, 63).set().map(choices -> new SetSchema("uint64", choices))
+            Arbitraries.integers().between(0, 7).set()
+                .ofMaxSize(8)
+                .map(choices -> new SetSchema("uint8", choices)),
+            Arbitraries.integers().between(0, 15).set()
+                .ofMaxSize(16)
+                .map(choices -> new SetSchema("uint16", choices)),
+            Arbitraries.integers().between(0, 31).set()
+                .ofMaxSize(32)
+                .map(choices -> new SetSchema("uint32", choices)),
+            Arbitraries.integers().between(0, 63).set()
+                .ofMaxSize(64)
+                .map(choices -> new SetSchema("uint64", choices))
         );
     }
 
@@ -213,14 +221,19 @@ private static Arbitrary<Encoding.Presence> presence()
 
     private static Arbitrary<VarDataSchema> varDataSchema()
     {
-        return Arbitraries.of(VarDataSchema.Encoding.values())
-            .map(VarDataSchema::new);
+        return Combinators.combine(
+            Arbitraries.of(VarDataSchema.Encoding.values()),
+            Arbitraries.of(
+                PrimitiveType.UINT8,
+                PrimitiveType.UINT16,
+                PrimitiveType.UINT32
+            )
+        ).as(VarDataSchema::new);
     }
 
     public static Arbitrary<MessageSchema> messageSchema()
     {
         return Combinators.combine(
-
             withDuplicates(
                 3,
                 Combinators.combine(

sbe-tool/src/propertyTest/java/uk/co/real_logic/sbe/properties/schema/TestXmlSchemaWriter.java

@@ -20,6 +20,7 @@
 import org.agrona.collections.MutableInteger;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
+import org.w3c.dom.Node;
 
 import java.io.File;
 import java.io.StringWriter;
@@ -74,7 +75,7 @@ private static void writeTo(
             final Element topLevelTypes = createTypesElement(document);
             root.appendChild(topLevelTypes);
 
-            final HashMap<TypeSchema, String> typeToName = new HashMap<>();
+            final HashMap<Object, String> typeToName = new HashMap<>();
 
             final TypeSchemaConverter typeSchemaConverter = new TypeSchemaConverter(
                 document,
@@ -88,7 +89,8 @@ private static void writeTo(
                 topLevelTypes,
                 typeSchemaConverter,
                 schema.blockFields().stream().map(FieldSchema::type).collect(Collectors.toList()),
-                schema.groups());
+                schema.groups(),
+                schema.varData());
 
             final Element message = document.createElement("sbe:message");
             message.setAttribute("name", "TestMessage");
@@ -129,7 +131,7 @@ private static void writeTo(
 
     private static void appendMembers(
         final Document document,
-        final HashMap<TypeSchema, String> typeToName,
+        final HashMap<Object, String> typeToName,
         final List<FieldSchema> blockFields,
         final List<GroupSchema> groups,
         final List<VarDataSchema> varData,
@@ -174,21 +176,10 @@ private static void appendMembers(
         for (final VarDataSchema data : varData)
         {
             final int id = nextMemberId.getAndIncrement();
-
             final Element element = document.createElement("data");
             element.setAttribute("id", Integer.toString(id));
             element.setAttribute("name", "member" + id);
-            switch (data.encoding())
-            {
-                case ASCII:
-                    element.setAttribute("type", "varStringEncoding");
-                    break;
-                case BYTES:
-                    element.setAttribute("type", "varDataEncoding");
-                    break;
-                default:
-                    throw new IllegalStateException("Unknown encoding: " + data.encoding());
-            }
+            element.setAttribute("type", requireNonNull(typeToName.get(data)));
             parent.appendChild(element);
         }
     }
@@ -213,27 +204,6 @@ private static Element createTypesElement(final Document document)
             createTypeElement(document, "numInGroup", "uint16")
         ));
 
-        final Element varString = createTypeElement(document, "varData", "uint8");
-        varString.setAttribute("length", "0");
-        varString.setAttribute("characterEncoding", "US-ASCII");
-        types.appendChild(createCompositeElement(
-            document,
-            "varStringEncoding",
-            createTypeElement(document, "length", "uint16"),
-            varString
-        ));
-
-        final Element varData = createTypeElement(document, "varData", "uint8");
-        final Element varDataLength = createTypeElement(document, "length", "uint32");
-        varDataLength.setAttribute("maxValue", "1000000");
-        varData.setAttribute("length", "0");
-        types.appendChild(createCompositeElement(
-            document,
-            "varDataEncoding",
-            varDataLength,
-            varData
-        ));
-
         return types;
     }
 
@@ -359,7 +329,8 @@ private static void appendTypes(
         final Element topLevelTypes,
         final TypeSchemaConverter typeSchemaConverter,
         final List<TypeSchema> blockFields,
-        final List<GroupSchema> groups)
+        final List<GroupSchema> groups,
+        final List<VarDataSchema> varDataFields)
     {
         for (final TypeSchema field : blockFields)
         {
@@ -376,23 +347,29 @@ private static void appendTypes(
                 topLevelTypes,
                 typeSchemaConverter,
                 group.blockFields().stream().map(FieldSchema::type).collect(Collectors.toList()),
-                group.groups()
-            );
+                group.groups(),
+                group.varData());
+        }
+
+        for (final VarDataSchema varData : varDataFields)
+        {
+            topLevelTypes.appendChild(typeSchemaConverter.convert(varData));
         }
     }
 
+    @SuppressWarnings("EnhancedSwitchMigration")
     private static final class TypeSchemaConverter implements TypeSchemaVisitor
     {
         private final Document document;
         private final Element topLevelTypes;
-        private final Map<TypeSchema, String> typeToName;
-        private final Function<TypeSchema, String> nextName;
+        private final Map<Object, String> typeToName;
+        private final Function<Object, String> nextName;
         private Element result;
 
         private TypeSchemaConverter(
             final Document document,
             final Element topLevelTypes,
-            final Map<TypeSchema, String> typeToName)
+            final Map<Object, String> typeToName)
         {
             this.document = document;
             this.topLevelTypes = topLevelTypes;
@@ -481,5 +458,31 @@ public Element convert(final TypeSchema type)
             type.accept(this);
             return requireNonNull(result);
         }
+
+        public Node convert(final VarDataSchema varData)
+        {
+            final Element lengthElement = createTypeElement(document, "length",
+                varData.lengthEncoding().primitiveName());
+
+            if (varData.lengthEncoding().size() >= 4)
+            {
+                lengthElement.setAttribute("maxValue", Integer.toString(1_000_000));
+            }
+
+            final Element varDataElement = createTypeElement(document, "varData", "uint8");
+            varDataElement.setAttribute("length", "0");
+
+            if (varData.dataEncoding().equals(VarDataSchema.Encoding.ASCII))
+            {
+                varDataElement.setAttribute("characterEncoding", "US-ASCII");
+            }
+
+            return createCompositeElement(
+                document,
+                typeToName.computeIfAbsent(varData, nextName),
+                lengthElement,
+                varDataElement
+            );
+        }
     }
 }

sbe-tool/src/propertyTest/java/uk/co/real_logic/sbe/properties/schema/VarDataSchema.java

@@ -16,18 +16,29 @@
 
 package uk.co.real_logic.sbe.properties.schema;
 
+import uk.co.real_logic.sbe.PrimitiveType;
+
 public final class VarDataSchema
 {
-    private final Encoding encoding;
+    private final Encoding dataEncoding;
+    private final PrimitiveType lengthEncoding;
+
+    public VarDataSchema(
+        final Encoding dataEncoding,
+        final PrimitiveType lengthEncoding)
+    {
+        this.dataEncoding = dataEncoding;
+        this.lengthEncoding = lengthEncoding;
+    }
 
-    public VarDataSchema(final Encoding encoding)
+    public Encoding dataEncoding()
     {
-        this.encoding = encoding;
+        return dataEncoding;
     }
 
-    public Encoding encoding()
+    public PrimitiveType lengthEncoding()
     {
-        return encoding;
+        return lengthEncoding;
     }
 
     public enum Encoding