fix: generic null field (#340)

Author: YongwuHe

arex-instrumentation-api/src/main/java/io/arex/inst/runtime/util/TypeUtil.java

@@ -134,10 +134,8 @@ private static String genericTypeToString(Object result) {
             if (isCollection(field.getType().getName())) {
                 genericType = filterRawGenericType(genericType);
             }
-
-            if (StringUtil.isNotEmpty(genericType)) {
-                builder.append(genericType);
-            }
+            genericType = StringUtil.isEmpty(genericType) ? DEFAULT_CLASS_NAME : genericType;
+            builder.append(genericType);
             if (i == typeParameters.length - 1) {
                return builder.toString();
             }

arex-instrumentation-api/src/test/java/io/arex/inst/runtime/util/TypeUtilTest.java

@@ -176,11 +176,15 @@ void testDoubleGenericType() {
 
         final Pair pairNull = Pair.of(System.currentTimeMillis(), null);
         final String genericNull = TypeUtil.getName(pairNull);
-        assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.Long,", genericNull);
+        assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.Long,java.lang.String", genericNull);
 
         final Pair pairList = Pair.of(System.currentTimeMillis(), Arrays.asList("mock"));
         final String genericList = TypeUtil.getName(pairList);
         assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.Long,java.util.Arrays$ArrayList-java.lang.String", genericList);
+
+        final Pair pairFirstNull = Pair.of(null, System.currentTimeMillis());
+        final String genericFirstNull = TypeUtil.getName(pairFirstNull);
+        assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.String,java.lang.Long", genericFirstNull);
     }
 
     @Test
@@ -369,7 +373,7 @@ void testGenericFieldInFather() {
         final ArrayList<Object> list = new ArrayList<>();
         childClass.setValue(list);
         String name = TypeUtil.getName(childClass);
-        assertEquals("io.arex.inst.runtime.util.TypeUtilTest$ChildClass-", name);
+        assertEquals("io.arex.inst.runtime.util.TypeUtilTest$ChildClass-java.lang.String", name);
         list.add("test");
         childClass.setValue(list);
         name = TypeUtil.getName(childClass);

arex-instrumentation-foundation/src/test/java/io/arex/foundation/serializer/GsonSerializerTest.java

@@ -5,9 +5,12 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import com.google.gson.internal.LinkedTreeMap;
+import io.arex.agent.bootstrap.internal.Pair;
 import io.arex.inst.runtime.util.TypeUtil;
 import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
 import it.unimi.dsi.fastutil.ints.IntSet;
+
+import java.lang.reflect.Type;
 import java.sql.Time;
 import java.time.LocalDateTime;
 import java.util.Map;
@@ -146,4 +149,26 @@ void testFastUtil() throws Throwable {
         assert deserialize != null;
         assertEquals(hashSet, deserialize);
     }
-}
+
+    @Test
+    void testNullField() {
+        final Pair<LocalDateTime, Long> pairFirstNull = Pair.of(null, System.currentTimeMillis());
+        final String genericFirstNull = TypeUtil.getName(pairFirstNull);
+        assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.String,java.lang.Long", genericFirstNull);
+        String json = GsonSerializer.INSTANCE.serialize(pairFirstNull);
+        System.out.println(json);
+        Type type1 = TypeUtil.forName(genericFirstNull);
+        Pair firstNulldeserialize = GsonSerializer.INSTANCE.deserialize(json, type1);
+        assertNull(firstNulldeserialize.getFirst());
+
+        final Pair pairNull = Pair.of(System.currentTimeMillis(), null);
+        final String genericNull = TypeUtil.getName(pairNull);
+        assertEquals("io.arex.agent.bootstrap.internal.Pair-java.lang.Long,java.lang.String", genericNull);
+        json = GsonSerializer.INSTANCE.serialize(pairNull);
+        System.out.println(json);
+        Type type2 = TypeUtil.forName(genericNull);
+        firstNulldeserialize = GsonSerializer.INSTANCE.deserialize(json, type2);
+        assertNull(firstNulldeserialize.getSecond());
+    }
+
+}