bugfix: fix #94

Author: kezhenxu94

src/main/kotlin/wu/seal/jsontokotlin/KotlinCodeMaker.kt

@@ -113,7 +113,11 @@ class KotlinCodeMaker {
         val classAnnotation = KClassAnnotation.getClassAnnotation(className.toString())
         stringBuilder.append(classAnnotation)
         if (classAnnotation.isNotBlank()) stringBuilder.append("\n")
-        stringBuilder.append("data class ").append(className).append("(\n")
+        if (inputElement?.isJsonNull == true || (inputElement as? JsonObject)?.entrySet()?.isEmpty() == true) {
+            stringBuilder.append("class ").append(className).append("(\n")
+        } else {
+            stringBuilder.append("data class ").append(className).append("(\n")
+        }
     }
 
 

src/test/kotlin/wu/seal/jsontokotlin/regression/Issue094Test.kt

@@ -0,0 +1,36 @@
+package wu.seal.jsontokotlin.regression
+
+import com.winterbe.expekt.should
+import org.junit.Before
+import org.junit.Test
+import wu.seal.jsontokotlin.KotlinCodeMaker
+import wu.seal.jsontokotlin.test.TestConfig
+
+/**
+ * Created by kezhenxu at 2018/12/30 11:45
+ *
+ * @author kezhenxu (kezhenxu94 at 163 dot com)
+ */
+class Issue094Test {
+    private val testJson = """
+    { "test": {} }
+    """.trimIndent()
+    private val expected = """
+data class A(
+    @SerializedName("test") val test: Test = Test()
+) {
+    
+    class Test(
+    )
+}"""
+
+    @Before
+    fun setUp() {
+        TestConfig.setToTestInitState()
+    }
+
+    @Test
+    fun testIssue087() {
+        KotlinCodeMaker("A", testJson).makeKotlinData().should.be.equal(expected)
+    }
+}