Java: fix unsigned default value code generation and add 'L' suffix for long default value (#4051)

* Java: emit "signed" equivalent of unsigned default value in generated code and add "L" suffix to long default value.

* Updated generated code

* Only convert ulong to "signed" equivalent. ubyte and ushort don't need specific handling as "user facing" type is int. uint need 'L' suffix as "user facing" type is long.

* Added missing cast to primitive type of default value which is in "user facing" type in builder.add<type>() calls.

* Do not cast default value to actual type in C#.

src/idl_gen_general.cpp

@@ -490,9 +490,21 @@ std::string GenDefaultValue(const Value &value, bool enableLangOverrides) {
       return GenEnumDefaultValue(value);
     }
   }
+
+  auto longSuffix = lang_.language == IDLOptions::kJava ? "L" : "";
   switch (value.type.base_type) {
     case BASE_TYPE_FLOAT: return value.constant + "f";
     case BASE_TYPE_BOOL: return value.constant == "0" ? "false" : "true";
+    case BASE_TYPE_ULONG: 
+    {
+      if (lang_.language != IDLOptions::kJava)
+        return value.constant;
+      // Converts the ulong into its bits signed equivalent
+      uint64_t defaultValue = StringToUInt(value.constant.c_str());
+      return NumToString(static_cast<int64_t>(defaultValue)) + longSuffix;
+    }
+    case BASE_TYPE_UINT:
+    case BASE_TYPE_LONG: return value.constant + longSuffix;
     default: return value.constant;
   }
 }
@@ -1240,7 +1252,10 @@ void GenStruct(StructDef &struct_def, std::string *code_ptr) {
           lang_.language == IDLOptions::kCSharp) {
         code += ".Value";
       }
-      code += ", " + GenDefaultValue(field.value, false);
+      code += ", ";
+      if (lang_.language == IDLOptions::kJava)
+        code += SourceCastBasic( field.value.type );
+      code += GenDefaultValue(field.value, false);
       code += "); }\n";
       if (field.value.type.base_type == BASE_TYPE_VECTOR) {
         auto vector_type = field.value.type.VectorType();

tests/MyGame/Example/Monster.java

@@ -61,19 +61,19 @@ public final class Monster extends Table {
   public boolean mutateTestbool(boolean testbool) { int o = __offset(34); if (o != 0) { bb.put(o + bb_pos, (byte)(testbool ? 1 : 0)); return true; } else { return false; } }
   public int testhashs32Fnv1() { int o = __offset(36); return o != 0 ? bb.getInt(o + bb_pos) : 0; }
   public boolean mutateTesthashs32Fnv1(int testhashs32_fnv1) { int o = __offset(36); if (o != 0) { bb.putInt(o + bb_pos, testhashs32_fnv1); return true; } else { return false; } }
-  public long testhashu32Fnv1() { int o = __offset(38); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0; }
+  public long testhashu32Fnv1() { int o = __offset(38); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0L; }
   public boolean mutateTesthashu32Fnv1(long testhashu32_fnv1) { int o = __offset(38); if (o != 0) { bb.putInt(o + bb_pos, (int)testhashu32_fnv1); return true; } else { return false; } }
-  public long testhashs64Fnv1() { int o = __offset(40); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public long testhashs64Fnv1() { int o = __offset(40); return o != 0 ? bb.getLong(o + bb_pos) : 0L; }
   public boolean mutateTesthashs64Fnv1(long testhashs64_fnv1) { int o = __offset(40); if (o != 0) { bb.putLong(o + bb_pos, testhashs64_fnv1); return true; } else { return false; } }
-  public long testhashu64Fnv1() { int o = __offset(42); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public long testhashu64Fnv1() { int o = __offset(42); return o != 0 ? bb.getLong(o + bb_pos) : 0L; }
   public boolean mutateTesthashu64Fnv1(long testhashu64_fnv1) { int o = __offset(42); if (o != 0) { bb.putLong(o + bb_pos, testhashu64_fnv1); return true; } else { return false; } }
   public int testhashs32Fnv1a() { int o = __offset(44); return o != 0 ? bb.getInt(o + bb_pos) : 0; }
   public boolean mutateTesthashs32Fnv1a(int testhashs32_fnv1a) { int o = __offset(44); if (o != 0) { bb.putInt(o + bb_pos, testhashs32_fnv1a); return true; } else { return false; } }
-  public long testhashu32Fnv1a() { int o = __offset(46); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0; }
+  public long testhashu32Fnv1a() { int o = __offset(46); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0L; }
   public boolean mutateTesthashu32Fnv1a(long testhashu32_fnv1a) { int o = __offset(46); if (o != 0) { bb.putInt(o + bb_pos, (int)testhashu32_fnv1a); return true; } else { return false; } }
-  public long testhashs64Fnv1a() { int o = __offset(48); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public long testhashs64Fnv1a() { int o = __offset(48); return o != 0 ? bb.getLong(o + bb_pos) : 0L; }
   public boolean mutateTesthashs64Fnv1a(long testhashs64_fnv1a) { int o = __offset(48); if (o != 0) { bb.putLong(o + bb_pos, testhashs64_fnv1a); return true; } else { return false; } }
-  public long testhashu64Fnv1a() { int o = __offset(50); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public long testhashu64Fnv1a() { int o = __offset(50); return o != 0 ? bb.getLong(o + bb_pos) : 0L; }
   public boolean mutateTesthashu64Fnv1a(long testhashu64_fnv1a) { int o = __offset(50); if (o != 0) { bb.putLong(o + bb_pos, testhashu64_fnv1a); return true; } else { return false; } }
   public boolean testarrayofbools(int j) { int o = __offset(52); return o != 0 ? 0!=bb.get(__vector(o) + j * 1) : false; }
   public int testarrayofboolsLength() { int o = __offset(52); return o != 0 ? __vector_len(o) : 0; }
@@ -114,13 +114,13 @@ public final class Monster extends Table {
   public static void addTestempty(FlatBufferBuilder builder, int testemptyOffset) { builder.addOffset(14, testemptyOffset, 0); }
   public static void addTestbool(FlatBufferBuilder builder, boolean testbool) { builder.addBoolean(15, testbool, false); }
   public static void addTesthashs32Fnv1(FlatBufferBuilder builder, int testhashs32Fnv1) { builder.addInt(16, testhashs32Fnv1, 0); }
-  public static void addTesthashu32Fnv1(FlatBufferBuilder builder, long testhashu32Fnv1) { builder.addInt(17, (int)testhashu32Fnv1, 0); }
-  public static void addTesthashs64Fnv1(FlatBufferBuilder builder, long testhashs64Fnv1) { builder.addLong(18, testhashs64Fnv1, 0); }
-  public static void addTesthashu64Fnv1(FlatBufferBuilder builder, long testhashu64Fnv1) { builder.addLong(19, testhashu64Fnv1, 0); }
+  public static void addTesthashu32Fnv1(FlatBufferBuilder builder, long testhashu32Fnv1) { builder.addInt(17, (int)testhashu32Fnv1, (int)0L); }
+  public static void addTesthashs64Fnv1(FlatBufferBuilder builder, long testhashs64Fnv1) { builder.addLong(18, testhashs64Fnv1, 0L); }
+  public static void addTesthashu64Fnv1(FlatBufferBuilder builder, long testhashu64Fnv1) { builder.addLong(19, testhashu64Fnv1, 0L); }
   public static void addTesthashs32Fnv1a(FlatBufferBuilder builder, int testhashs32Fnv1a) { builder.addInt(20, testhashs32Fnv1a, 0); }
-  public static void addTesthashu32Fnv1a(FlatBufferBuilder builder, long testhashu32Fnv1a) { builder.addInt(21, (int)testhashu32Fnv1a, 0); }
-  public static void addTesthashs64Fnv1a(FlatBufferBuilder builder, long testhashs64Fnv1a) { builder.addLong(22, testhashs64Fnv1a, 0); }
-  public static void addTesthashu64Fnv1a(FlatBufferBuilder builder, long testhashu64Fnv1a) { builder.addLong(23, testhashu64Fnv1a, 0); }
+  public static void addTesthashu32Fnv1a(FlatBufferBuilder builder, long testhashu32Fnv1a) { builder.addInt(21, (int)testhashu32Fnv1a, (int)0L); }
+  public static void addTesthashs64Fnv1a(FlatBufferBuilder builder, long testhashs64Fnv1a) { builder.addLong(22, testhashs64Fnv1a, 0L); }
+  public static void addTesthashu64Fnv1a(FlatBufferBuilder builder, long testhashu64Fnv1a) { builder.addLong(23, testhashu64Fnv1a, 0L); }
   public static void addTestarrayofbools(FlatBufferBuilder builder, int testarrayofboolsOffset) { builder.addOffset(24, testarrayofboolsOffset, 0); }
   public static int createTestarrayofboolsVector(FlatBufferBuilder builder, boolean[] data) { builder.startVector(1, data.length, 1); for (int i = data.length - 1; i >= 0; i--) builder.addBoolean(data[i]); return builder.endVector(); }
   public static void startTestarrayofboolsVector(FlatBufferBuilder builder, int numElems) { builder.startVector(1, numElems, 1); }

tests/MyGame/Example/Stat.java

@@ -16,7 +16,7 @@ public final class Stat extends Table {
 
   public String id() { int o = __offset(4); return o != 0 ? __string(o + bb_pos) : null; }
   public ByteBuffer idAsByteBuffer() { return __vector_as_bytebuffer(4, 1); }
-  public long val() { int o = __offset(6); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public long val() { int o = __offset(6); return o != 0 ? bb.getLong(o + bb_pos) : 0L; }
   public boolean mutateVal(long val) { int o = __offset(6); if (o != 0) { bb.putLong(o + bb_pos, val); return true; } else { return false; } }
   public int count() { int o = __offset(8); return o != 0 ? bb.getShort(o + bb_pos) & 0xFFFF : 0; }
   public boolean mutateCount(int count) { int o = __offset(8); if (o != 0) { bb.putShort(o + bb_pos, (short)count); return true; } else { return false; } }
@@ -34,8 +34,8 @@ public final class Stat extends Table {
 
   public static void startStat(FlatBufferBuilder builder) { builder.startObject(3); }
   public static void addId(FlatBufferBuilder builder, int idOffset) { builder.addOffset(0, idOffset, 0); }
-  public static void addVal(FlatBufferBuilder builder, long val) { builder.addLong(1, val, 0); }
-  public static void addCount(FlatBufferBuilder builder, int count) { builder.addShort(2, (short)count, 0); }
+  public static void addVal(FlatBufferBuilder builder, long val) { builder.addLong(1, val, 0L); }
+  public static void addCount(FlatBufferBuilder builder, int count) { builder.addShort(2, (short)count, (short)0); }
   public static int endStat(FlatBufferBuilder builder) {
     int o = builder.endObject();
     return o;