ModelUtils: isMap only if additionalProperties is a Schema (#410)

Fix for issue #409

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java

@@ -304,7 +304,7 @@ public static boolean isMapSchema(Schema schema) {
         if (schema instanceof MapSchema) {
             return true;
         }
-        if (schema.getAdditionalProperties() != null) {
+        if (schema.getAdditionalProperties() instanceof Schema) {
             return true;
         }
         return false;

modules/openapi-generator/src/test/java/org/openapitools/codegen/html/StaticHtmlGeneratorTest.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
+ * Copyright 2018 SmartBear Software
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.openapitools.codegen.html;
+
+import io.swagger.v3.oas.models.media.IntegerSchema;
+import io.swagger.v3.oas.models.media.ObjectSchema;
+import io.swagger.v3.oas.models.media.Schema;
+import io.swagger.v3.oas.models.media.StringSchema;
+
+import org.openapitools.codegen.CodegenModel;
+import org.openapitools.codegen.languages.StaticHtmlGenerator;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.util.Collections;
+
+public class StaticHtmlGeneratorTest {
+
+    @Test
+    public void testAdditionalPropertiesFalse() {
+        final StaticHtmlGenerator codegen = new StaticHtmlGenerator();
+
+        Schema schema = new ObjectSchema()
+                .additionalProperties(false)
+                .addProperties("id", new IntegerSchema())
+                .addProperties("name", new StringSchema());
+        CodegenModel cm = codegen.fromModel("test", schema, Collections.emptyMap());
+        Assert.assertNotNull(cm);
+    }
+
+}