[all] Support for Free-Form Objects (#849)

Consider "additionalProperties: true"

Fixes #796

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

@@ -75,7 +75,6 @@ import java.util.TreeSet;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 public class DefaultCodegen implements CodegenConfig {
     private static final Logger LOGGER = LoggerFactory.getLogger(DefaultCodegen.class);
@@ -1094,7 +1093,7 @@ public class DefaultCodegen implements CodegenConfig {
      */
     public String toInstantiationType(Schema schema) {
         if (ModelUtils.isMapSchema(schema)) {
-            Schema additionalProperties = (Schema) schema.getAdditionalProperties();
+            Schema additionalProperties = ModelUtils.getAdditionalProperties(schema);
             String type = additionalProperties.getType();
             if (null == type) {
                 LOGGER.error("No Type defined for Additional Property " + additionalProperties + "\n" //
@@ -1998,7 +1997,7 @@ public class DefaultCodegen implements CodegenConfig {
             property.maxItems = p.getMaxProperties();
 
             // handle inner property
-            CodegenProperty cp = fromProperty("inner", (Schema) p.getAdditionalProperties());
+            CodegenProperty cp = fromProperty("inner", ModelUtils.getAdditionalProperties(p));
             updatePropertyForMap(property, cp);
         } else { // model
             // TODO revise the logic below
@@ -2288,7 +2287,7 @@ public class DefaultCodegen implements CodegenConfig {
                         CodegenProperty innerProperty = fromProperty("response", as.getItems());
                         op.returnBaseType = innerProperty.baseType;
                     } else if (ModelUtils.isMapSchema(responseSchema)) {
-                        CodegenProperty innerProperty = fromProperty("response", (Schema) responseSchema.getAdditionalProperties());
+                        CodegenProperty innerProperty = fromProperty("response", ModelUtils.getAdditionalProperties(responseSchema));
                         op.returnBaseType = innerProperty.baseType;
                     } else {
                         if (cm.complexType != null) {
@@ -2674,7 +2673,7 @@ public class DefaultCodegen implements CodegenConfig {
                 }
 
             } else if (ModelUtils.isMapSchema(parameterSchema)) { // for map parameter
-                CodegenProperty codegenProperty = fromProperty("inner", (Schema) parameterSchema.getAdditionalProperties());
+                CodegenProperty codegenProperty = fromProperty("inner", ModelUtils.getAdditionalProperties(parameterSchema));
                 codegenParameter.items = codegenProperty;
                 codegenParameter.mostInnerItems = codegenProperty.mostInnerItems;
                 codegenParameter.baseType = codegenProperty.dataType;
@@ -4381,7 +4380,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         if (ModelUtils.isMapSchema(schema)) {
-            Schema inner = (Schema) schema.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(schema);
             if (inner == null) {
                 inner = new StringSchema().description("//TODO automatically added by openapi-generator");
                 schema.setAdditionalProperties(inner);
@@ -4469,7 +4468,7 @@ public class DefaultCodegen implements CodegenConfig {
                 imports.add(codegenParameter.baseType);
             } else {
                 CodegenProperty codegenProperty = fromProperty("property", schema);
-                if (schema.getAdditionalProperties() != null) {// http body is map
+                if (ModelUtils.getAdditionalProperties(schema) != null) {// http body is map
                     LOGGER.error("Map should be supported. Please report to openapi-generator github repo about the issue.");
                 } else if (codegenProperty != null) {
                     String codegenModelName, codegenModelDescription;

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

@@ -238,7 +238,7 @@ public class InlineModelResolver {
                                     }
                                 } else if (property instanceof MapSchema) {
                                     MapSchema mp = (MapSchema) property;
-                                    Schema innerProperty = (Schema) mp.getAdditionalProperties();
+                                    Schema innerProperty = ModelUtils.getAdditionalProperties(mp);
                                     if (innerProperty instanceof ObjectSchema) {
                                         ObjectSchema op = (ObjectSchema) innerProperty;
                                         if (op.getProperties() != null && op.getProperties().size() > 0) {
@@ -431,7 +431,7 @@ public class InlineModelResolver {
                 }
             }
             if (ModelUtils.isMapSchema(property)) {
-                Schema inner = (Schema) property.getAdditionalProperties();
+                Schema inner = ModelUtils.getAdditionalProperties(property);
                 if (inner instanceof ObjectSchema) {
                     ObjectSchema op = (ObjectSchema) inner;
                     if (op.getProperties() != null && op.getProperties().size() > 0) {
@@ -519,7 +519,7 @@ public class InlineModelResolver {
         model.setDescription(description);
         model.setName(object.getName());
         model.setExample(example);
-        model.setItems((Schema) object.getAdditionalProperties());
+        model.setItems(ModelUtils.getAdditionalProperties(object));
         return model;
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java

@@ -236,10 +236,10 @@ public class ExampleGenerator {
             Map<String, Object> mp = new HashMap<String, Object>();
             if (property.getName() != null) {
                 mp.put(property.getName(),
-                        resolvePropertyToExample(propertyName, mediaType, (Schema) property.getAdditionalProperties(), processedModels));
+                        resolvePropertyToExample(propertyName, mediaType, ModelUtils.getAdditionalProperties(property), processedModels));
             } else {
                 mp.put("key",
-                        resolvePropertyToExample(propertyName, mediaType, (Schema) property.getAdditionalProperties(), processedModels));
+                        resolvePropertyToExample(propertyName, mediaType, ModelUtils.getAdditionalProperties(property), processedModels));
             }
             return mp;
         } else if (ModelUtils.isUUIDSchema(property)) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractAdaCodegen.java

@@ -329,7 +329,7 @@ abstract public class AbstractAdaCodegen extends DefaultCodegen implements Codeg
             return getTypeDeclaration(inner) + "_Vectors.Vector";
         }
         if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             String name = getTypeDeclaration(inner) + "_Map";
             if (name.startsWith("Swagger.")) {
                 return name;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java

@@ -18,12 +18,12 @@
 package org.openapitools.codegen.languages;
 
 import java.util.*;
-import org.apache.commons.lang3.StringUtils;
 import com.google.common.base.Strings;
+import org.apache.commons.lang3.StringUtils;
+import org.openapitools.codegen.CodegenConfig;
+import org.openapitools.codegen.CodegenModel;
 import org.openapitools.codegen.CodegenOperation;
 import org.openapitools.codegen.CodegenParameter;
-import org.openapitools.codegen.CodegenModel;
-import org.openapitools.codegen.CodegenConfig;
 import org.openapitools.codegen.CodegenProperty;
 import org.openapitools.codegen.CodegenType;
 import org.openapitools.codegen.DefaultCodegen;
@@ -196,7 +196,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
             }
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             if (inner == null) {
                 LOGGER.warn(p.getName() + "(map property) does not have a proper inner type defined");
@@ -229,11 +229,11 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
         } else if (ModelUtils.isMapSchema(p)) {
             final MapSchema ap = (MapSchema) p;
             final String pattern = "new HashMap<%s>()";
-            if (ap.getAdditionalProperties() == null) {
+            if (ModelUtils.getAdditionalProperties(ap) == null) {
                 return null;
             }
 
-            return String.format(pattern, String.format("String, %s", getTypeDeclaration((Schema) ap.getAdditionalProperties())));
+            return String.format(pattern, String.format("String, %s", getTypeDeclaration(ModelUtils.getAdditionalProperties(ap))));
         } else if (ModelUtils.isLongSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString() + "l";
@@ -366,7 +366,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
         } else if (ModelUtils.isLongSchema(p)) {
             example = example.isEmpty() ? "123456789L" : example + "L";
         } else if (ModelUtils.isMapSchema(p)) {
-            example = "new " + getTypeDeclaration(p) + "{'key'=>" + toExampleValue((Schema) p.getAdditionalProperties()) + "}";
+            example = "new " + getTypeDeclaration(p) + "{'key'=>" + toExampleValue(ModelUtils.getAdditionalProperties(p)) + "}";
 
         } else if (ModelUtils.isPasswordSchema(p)) {
             example = example.isEmpty() ? "password123" : escapeText(example);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java

@@ -811,7 +811,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
             return getArrayTypeDeclaration((ArraySchema) p);
         } else if (ModelUtils.isMapSchema(p)) {
             // Should we also support maps of maps?
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<string, " + getTypeDeclaration(inner) + ">";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractEiffelCodegen.java

@@ -290,7 +290,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
             Schema inner = ap.getItems();
             return "LIST [" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         }
@@ -557,7 +557,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            Schema additionalProperties2 = (Schema) p.getAdditionalProperties();
+            Schema additionalProperties2 = ModelUtils.getAdditionalProperties(p);
             String type = additionalProperties2.getType();
             if (null == type) {
                 LOGGER.error("No Type defined for Additional Schema " + additionalProperties2 + "\n" //

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java

@@ -258,7 +258,7 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
             Schema inner = ap.getItems();
             return "[]" + getTypeDeclaration(inner);
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[string]" + getTypeDeclaration(inner);
         }
         //return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -679,7 +679,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             }
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             if (inner == null) {
                 LOGGER.warn(p.getName() + "(map property) does not have a proper inner type defined. Default to string");
                 inner = new StringSchema().description("TODO default missing array inner type to string");
@@ -728,11 +728,11 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             } else {
                 pattern = "new HashMap<%s>()";
             }
-            if (p.getAdditionalProperties() == null) {
+            if (ModelUtils.getAdditionalProperties(p) == null) {
                 return null;
             }
 
-            String typeDeclaration = String.format("String, %s", getTypeDeclaration((Schema) p.getAdditionalProperties()));
+            String typeDeclaration = String.format("String, %s", getTypeDeclaration(ModelUtils.getAdditionalProperties(p)));
             Object java8obj = additionalProperties.get("java8");
             if (java8obj != null) {
                 Boolean java8 = Boolean.valueOf(java8obj.toString());

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java

@@ -282,7 +282,7 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
         if (ModelUtils.isArraySchema(p)) {
             return getArrayTypeDeclaration((ArraySchema) p);
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             // Maps will be keyed only by primitive Kotlin string
             return getSchemaType(p) + "<kotlin.String, " + getTypeDeclaration(inner) + ">";

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java

@@ -332,7 +332,7 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner) + "[]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[string," + getTypeDeclaration(inner) + "]";
         } else if (StringUtils.isNotBlank(p.get$ref())) { // model
             String type = super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java

@@ -88,7 +88,7 @@ abstract class AbstractRubyCodegen extends DefaultCodegen implements CodegenConf
             Schema inner = ((ArraySchema) schema).getItems();
             return getSchemaType(schema) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(schema)) {
-            Schema inner = (Schema) schema.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(schema);
             return getSchemaType(schema) + "<String, " + getTypeDeclaration(inner) + ">";
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java

@@ -181,7 +181,7 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
@@ -206,7 +206,7 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return instantiationTypes.get("map") + "[String, " + inner + "]";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
@@ -235,7 +235,7 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
         } else if (ModelUtils.isIntegerSchema(p)) {
             return null;
         } else if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "new HashMap[String, " + inner + "]() ";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java

@@ -227,7 +227,7 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "{ [key: string]: " + getTypeDeclaration(inner) + "; }";
         } else if (ModelUtils.isFileSchema(p)) {
             return "any";
@@ -246,7 +246,7 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
             inner = mp1.getItems();
             return this.getSchemaType(p) + "<" + this.getParameterDataType(parameter, inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            inner = (Schema) p.getAdditionalProperties();
+            inner = ModelUtils.getAdditionalProperties(p);
             return "{ [key: string]: " + this.getParameterDataType(parameter, inner) + "; }";
         } else if (ModelUtils.isStringSchema(p)) {
             // Handle string enums

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AndroidClientCodegen.java

@@ -189,7 +189,7 @@ public class AndroidClientCodegen extends DefaultCodegen implements CodegenConfi
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "<String, " + getTypeDeclaration(inner) + ">";
         }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ApexClientCodegen.java

@@ -227,7 +227,7 @@ public class ApexClientCodegen extends AbstractApexCodegen {
             Long def = (Long) p.getDefault();
             out = def == null ? out : def.toString() + "L";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             String s = inner == null ? "Object" : getTypeDeclaration(inner);
             out = String.format("new Map<String, %s>()", s);
         } else if (ModelUtils.isStringSchema(p)) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/BashClientCodegen.java

@@ -388,7 +388,7 @@ public class BashClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ConfluenceWikiCodegen.java

@@ -99,7 +99,7 @@ public class ConfluenceWikiCodegen extends DefaultCodegen implements CodegenConf
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppPistacheServerCodegen.java

@@ -305,7 +305,7 @@ public class CppPistacheServerCodegen extends AbstractCppCodegen {
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         }
         if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<std::string, " + getTypeDeclaration(inner) + ">";
         }
         else if (ModelUtils.isByteArraySchema(p)) {
@@ -343,7 +343,7 @@ public class CppPistacheServerCodegen extends AbstractCppCodegen {
         else if (ModelUtils.isByteArraySchema(p)) {
             return "\"\"";
         } else if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "std::map<std::string, " + inner + ">()";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5ClientCodegen.java

@@ -294,7 +294,7 @@ public class CppQt5ClientCodegen extends AbstractCppCodegen implements CodegenCo
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">*";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<QString, " + getTypeDeclaration(inner) + ">*";
         }
         if (foundationClasses.contains(openAPIType)) {
@@ -325,7 +325,7 @@ public class CppQt5ClientCodegen extends AbstractCppCodegen implements CodegenCo
             }
             return "0";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "new QMap<QString, " + getTypeDeclaration(inner) + ">()";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5QHttpEngineServerCodegen.java

@@ -323,7 +323,7 @@ public class CppQt5QHttpEngineServerCodegen extends AbstractCppCodegen implement
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<QString, " + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isBinarySchema(p)) {
             return getSchemaType(p) + "*";
@@ -359,7 +359,7 @@ public class CppQt5QHttpEngineServerCodegen extends AbstractCppCodegen implement
             }
             return "0";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "QMap<QString, " + getTypeDeclaration(inner) + ">()";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java

@@ -308,7 +308,7 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<utility::string_t, " + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isStringSchema(p)
                 || ModelUtils.isDateSchema(p) || ModelUtils.isDateTimeSchema(p)
@@ -339,7 +339,7 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
             }
             return "0";
         } else if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "std::map<utility::string_t, " + inner + ">()";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestbedServerCodegen.java

@@ -270,7 +270,7 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "<std::string, " + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isByteArraySchema(p)) {
             return "std::string";
@@ -307,7 +307,7 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
         } else if (ModelUtils.isByteArraySchema(p)) {
             return "\"\"";
         } else if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "std::map<std::string, " + inner + ">()";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartClientCodegen.java

@@ -307,7 +307,7 @@ public class DartClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "<String, " + getTypeDeclaration(inner) + ">";
         }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java

@@ -447,7 +447,7 @@ public class ElixirClientCodegen extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "%{optional(String.t) => " + getTypeDeclaration(inner) + "}";
         } else if (ModelUtils.isPasswordSchema(p)) {
             return "String.t";

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java

@@ -486,7 +486,7 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/FinchServerCodegen.java

@@ -239,7 +239,7 @@ public class FinchServerCodegen extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java

@@ -548,7 +548,7 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "(Map.Map String " + getTypeDeclaration(inner) + ")";
         }
         return super.getTypeDeclaration(p);
@@ -570,7 +570,7 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            Schema additionalProperties2 = (Schema) p.getAdditionalProperties();
+            Schema additionalProperties2 = ModelUtils.getAdditionalProperties(p);
             String type = additionalProperties2.getType();
             if (null == type) {
                 LOGGER.error("No Type defined for Additional Schema " + additionalProperties2 + "\n" //

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java

@@ -293,7 +293,7 @@ public class HaskellServantCodegen extends DefaultCodegen implements CodegenConf
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "Map.Map String " + getTypeDeclaration(inner);
         }
         return fixModelChars(super.getTypeDeclaration(p));
@@ -328,7 +328,7 @@ public class HaskellServantCodegen extends DefaultCodegen implements CodegenConf
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            Schema additionalProperties2 = (Schema) p.getAdditionalProperties();
+            Schema additionalProperties2 = ModelUtils.getAdditionalProperties(p);
             String type = additionalProperties2.getType();
             if (null == type) {
                 LOGGER.error("No Type defined for Additional Property " + additionalProperties2 + "\n" //

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JMeterClientCodegen.java

@@ -174,7 +174,7 @@ public class JMeterClientCodegen extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClientCodegen.java

@@ -601,7 +601,7 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "{String: " + getTypeDeclaration(inner) + "}";
         }
         return super.getTypeDeclaration(p);
@@ -863,9 +863,9 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
                 codegenModel.getVendorExtensions().put("x-itemType", getSchemaType(am.getItems()));
             }
         } else if (ModelUtils.isMapSchema(model)) {
-            if (model.getAdditionalProperties() != null) {
+            if (ModelUtils.getAdditionalProperties(model) != null) {
                 codegenModel.getVendorExtensions().put("x-isMap", true);
-                codegenModel.getVendorExtensions().put("x-itemType", getSchemaType((Schema) model.getAdditionalProperties()));
+                codegenModel.getVendorExtensions().put("x-itemType", getSchemaType(ModelUtils.getAdditionalProperties(model)));
             } else {
                 String type = model.getType();
                 if (isPrimitiveType(type)){

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClosureAngularClientCodegen.java

@@ -236,7 +236,7 @@ public class JavascriptClosureAngularClientCodegen extends DefaultCodegen implem
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<!" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "Object<!string, "+ getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isFileSchema(p)) {
             return "Object";

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptFlowtypedClientCodegen.java

@@ -119,7 +119,7 @@ public class JavascriptFlowtypedClientCodegen extends AbstractTypeScriptClientCo
 
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
-        codegenModel.additionalPropertiesType = getTypeDeclaration((Schema) schema.getAdditionalProperties());
+        codegenModel.additionalPropertiesType = getTypeDeclaration(ModelUtils.getAdditionalProperties(schema));
         addImport(codegenModel, codegenModel.additionalPropertiesType);
     }
 
@@ -141,7 +141,7 @@ public class JavascriptFlowtypedClientCodegen extends AbstractTypeScriptClientCo
             inner = ((ArraySchema) p).getItems();
             return this.getSchemaType(p) + "<" + this.getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            inner = (Schema) p.getAdditionalProperties();
+            inner = ModelUtils.getAdditionalProperties(p);
             return "{ [key: string]: " + this.getTypeDeclaration(inner) + "; }";
         } else if (ModelUtils.isFileSchema(p)) {
             return "any";

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/LuaClientCodegen.java

@@ -337,7 +337,7 @@ public class LuaClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ObjcClientCodegen.java

@@ -377,7 +377,7 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
                 return getSchemaType(p) + "<" + innerTypeDeclaration + ">*";
             }
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             String innerTypeDeclaration = getTypeDeclaration(inner);
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PerlClientCodegen.java

@@ -220,7 +220,7 @@ public class PerlClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[string," + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java

@@ -163,7 +163,7 @@ public class PhpSilexServerCodegen extends DefaultCodegen implements CodegenConf
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[string," + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java

@@ -497,7 +497,7 @@ public class PhpSymfonyServerCodegen extends AbstractPhpCodegen implements Codeg
         }
 
         if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java

@@ -383,7 +383,7 @@ public class PowerShellClientCodegen extends DefaultCodegen implements CodegenCo
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner) + "[]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             // TODO not sure if the following map/hash declaration is correct
             return "{String, " + getTypeDeclaration(inner) + "}";
         } else if (!languageSpecificPrimitives.contains(getSchemaType(p))) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java

@@ -404,7 +404,7 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
 
             return getSchemaType(p) + "(str, " + getTypeDeclaration(inner) + ")";
         }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonFlaskConnexionServerCodegen.java

@@ -289,7 +289,7 @@ public class PythonFlaskConnexionServerCodegen extends DefaultCodegen implements
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[str, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java

@@ -286,7 +286,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java

@@ -288,7 +288,7 @@ public class RustClientCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return "Vec<" + getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "::std::collections::HashMap<String, " + getTypeDeclaration(inner) + ">";
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java

@@ -730,7 +730,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
             typeDeclaration.append(innerType).append(">");
             return typeDeclaration.toString();
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             String innerType = getTypeDeclaration(inner);
             StringBuilder typeDeclaration = new StringBuilder(typeMapping.get("map")).append("<").append(typeMapping.get("string")).append(", ");
             typeDeclaration.append(innerType).append(">");
@@ -797,7 +797,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return instantiationTypes.get("array") + "<" + getSchemaType(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return instantiationTypes.get("map") + "<" + typeMapping.get("string") + ", " + getSchemaType(inner) + ">";
         } else {
             return null;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaAkkaClientCodegen.java

@@ -276,7 +276,7 @@ public class ScalaAkkaClientCodegen extends AbstractScalaCodegen implements Code
         } else if (ModelUtils.isIntegerSchema(p)) {
             return null;
         } else if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "Map[String, " + inner + "].empty ";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaGatlingCodegen.java

@@ -347,7 +347,7 @@ public class ScalaGatlingCodegen extends AbstractScalaCodegen implements Codegen
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtml2Generator.java

@@ -131,7 +131,7 @@ public class StaticHtml2Generator extends DefaultCodegen implements CodegenConfi
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtmlGenerator.java

@@ -118,7 +118,7 @@ public class StaticHtmlGenerator extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift3Codegen.java

@@ -230,7 +230,7 @@ public class Swift3Codegen extends DefaultCodegen implements CodegenConfig {
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
 
-        final Schema additionalProperties = (Schema) schema.getAdditionalProperties();
+        final Schema additionalProperties = ModelUtils.getAdditionalProperties(schema);
 
         if (additionalProperties != null) {
             codegenModel.additionalPropertiesType = getSchemaType(additionalProperties);
@@ -333,7 +333,7 @@ public class Swift3Codegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "[String:" + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);
@@ -422,7 +422,7 @@ public class Swift3Codegen extends DefaultCodegen implements CodegenConfig {
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            return getSchemaType((Schema) p.getAdditionalProperties());
+            return getSchemaType(ModelUtils.getAdditionalProperties(p));
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift4Codegen.java

@@ -284,7 +284,7 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel,
                                                        Schema schema) {
 
-        final Schema additionalProperties = (Schema) schema.getAdditionalProperties();
+        final Schema additionalProperties = ModelUtils.getAdditionalProperties(schema);
 
         if (additionalProperties != null) {
             codegenModel.additionalPropertiesType = getSchemaType(additionalProperties);
@@ -420,7 +420,7 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "[String:" + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);
@@ -524,7 +524,7 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            return getSchemaType((Schema) p.getAdditionalProperties());
+            return getSchemaType(ModelUtils.getAdditionalProperties(p));
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SwiftClientCodegen.java

@@ -270,7 +270,7 @@ public class SwiftClientCodegen extends DefaultCodegen implements CodegenConfig
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = (Schema) p.getAdditionalProperties();
+            Schema inner = ModelUtils.getAdditionalProperties(p);
             return "[String:" + getTypeDeclaration(inner) + "]";
         }
         return super.getTypeDeclaration(p);
@@ -359,7 +359,7 @@ public class SwiftClientCodegen extends DefaultCodegen implements CodegenConfig
     @Override
     public String toInstantiationType(Schema p) {
         if (ModelUtils.isMapSchema(p)) {
-            String inner = getSchemaType((Schema) p.getAdditionalProperties());
+            String inner = getSchemaType(ModelUtils.getAdditionalProperties(p));
             return "[String:" + inner + "]";
         } else if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java

@@ -98,7 +98,7 @@ public class TypeScriptAngularClientCodegen extends AbstractTypeScriptClientCode
 
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
-        codegenModel.additionalPropertiesType = getTypeDeclaration((Schema) schema.getAdditionalProperties());
+        codegenModel.additionalPropertiesType = getTypeDeclaration(ModelUtils.getAdditionalProperties(schema));
         addImport(codegenModel, codegenModel.additionalPropertiesType);
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java

@@ -114,7 +114,7 @@ public class TypeScriptFetchClientCodegen extends AbstractTypeScriptClientCodege
             inner = ((ArraySchema) p).getItems();
             return this.getSchemaType(p) + "<" + this.getTypeDeclaration(inner) + ">";
         } else if (ModelUtils.isMapSchema(p)) {
-            inner = (Schema) p.getAdditionalProperties();
+            inner = ModelUtils.getAdditionalProperties(p);
             return "{ [key: string]: " + this.getTypeDeclaration(inner) + "; }";
         } else if (ModelUtils.isFileSchema(p)) {
             return "any";
@@ -127,7 +127,7 @@ public class TypeScriptFetchClientCodegen extends AbstractTypeScriptClientCodege
 
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
-        codegenModel.additionalPropertiesType = getTypeDeclaration((Schema) schema.getAdditionalProperties());
+        codegenModel.additionalPropertiesType = getTypeDeclaration(ModelUtils.getAdditionalProperties(schema));
         addImport(codegenModel, codegenModel.additionalPropertiesType);
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptInversifyClientCodegen.java

@@ -22,6 +22,7 @@ import io.swagger.v3.oas.models.media.FileSchema;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.parser.util.SchemaTypeUtil;
 import org.openapitools.codegen.*;
+import org.openapitools.codegen.utils.ModelUtils;
 
 import java.io.File;
 import java.text.SimpleDateFormat;
@@ -77,7 +78,7 @@ public class TypeScriptInversifyClientCodegen extends AbstractTypeScriptClientCo
 
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
-        codegenModel.additionalPropertiesType = getTypeDeclaration((Schema) schema.getAdditionalProperties());
+        codegenModel.additionalPropertiesType = getTypeDeclaration(ModelUtils.getAdditionalProperties(schema));
         addImport(codegenModel, codegenModel.additionalPropertiesType);
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptJqueryClientCodegen.java

@@ -136,7 +136,7 @@ public class TypeScriptJqueryClientCodegen extends AbstractTypeScriptClientCodeg
 
     @Override
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
-        codegenModel.additionalPropertiesType = getSchemaType((Schema) schema.getAdditionalProperties());
+        codegenModel.additionalPropertiesType = getSchemaType(ModelUtils.getAdditionalProperties(schema));
         addImport(codegenModel, codegenModel.additionalPropertiesType);
     }
 

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

@@ -307,6 +307,9 @@ public class ModelUtils {
         if (schema.getAdditionalProperties() instanceof Schema) {
             return true;
         }
+        if (schema.getAdditionalProperties() instanceof Boolean && (Boolean)schema.getAdditionalProperties()) {
+            return true;
+        }
         return false;
     }
 
@@ -657,4 +660,14 @@ public class ModelUtils {
         return schema;
     }
 
+    public static Schema getAdditionalProperties(Schema schema) {
+        if(schema.getAdditionalProperties() instanceof Schema) {
+            return (Schema) schema.getAdditionalProperties();
+        }
+        if(schema.getAdditionalProperties() instanceof Boolean && (Boolean)schema.getAdditionalProperties()) {
+            return new ObjectSchema();
+        }
+        return null;
+    }
+
 }

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

@@ -37,8 +37,6 @@ import io.swagger.v3.parser.util.SchemaTypeUtil;
 import org.openapitools.codegen.ClientOptInput;
 import org.openapitools.codegen.CodegenConstants;
 import org.openapitools.codegen.CodegenModel;
-import org.openapitools.codegen.CodegenModelFactory;
-import org.openapitools.codegen.CodegenModelType;
 import org.openapitools.codegen.CodegenOperation;
 import org.openapitools.codegen.CodegenParameter;
 import org.openapitools.codegen.CodegenProperty;
@@ -307,6 +305,35 @@ public class JavaClientCodegenTest {
         output.deleteOnExit();
     }
 
+    @Test
+    public void testFreeFormObjects() {
+        final OpenAPI openAPI = new OpenAPIParser().readLocation("src/test/resources/3_0/issue796.yaml", null, new ParseOptions()).getOpenAPI();
+        JavaClientCodegen codegen = new JavaClientCodegen();
+
+        Schema test1 = openAPI.getComponents().getSchemas().get("MapTest1");
+        CodegenModel cm1 = codegen.fromModel("MapTest1", test1, openAPI.getComponents().getSchemas());
+        Assert.assertEquals(cm1.getDataType(), "Map");
+        Assert.assertEquals(cm1.getParent(), "HashMap<String, Object>");
+        Assert.assertEquals(cm1.getClassname(), "MapTest1");
+
+        Schema test2 = openAPI.getComponents().getSchemas().get("MapTest2");
+        CodegenModel cm2 = codegen.fromModel("MapTest2", test2, openAPI.getComponents().getSchemas());
+        Assert.assertEquals(cm2.getDataType(), "Map");
+        Assert.assertEquals(cm2.getParent(), "HashMap<String, Object>");
+        Assert.assertEquals(cm2.getClassname(), "MapTest2");
+
+        Schema test3 = openAPI.getComponents().getSchemas().get("MapTest3");
+        CodegenModel cm3 = codegen.fromModel("MapTest3", test3, openAPI.getComponents().getSchemas());
+        Assert.assertEquals(cm3.getDataType(), "Map");
+        Assert.assertEquals(cm3.getParent(), "HashMap<String, Object>");
+        Assert.assertEquals(cm3.getClassname(), "MapTest3");
+
+        Schema other = openAPI.getComponents().getSchemas().get("OtherObj");
+        CodegenModel cm = codegen.fromModel("OtherObj", other, openAPI.getComponents().getSchemas());
+        Assert.assertEquals(cm.getDataType(), "Object");
+        Assert.assertEquals(cm.getClassname(), "OtherObj");
+    }
+
     private void ensureContainsFile(Map<String, String> generatedFiles, File root, String filename) {
         File file = new File(root, filename);
         String absoluteFilename = file.getAbsolutePath().replace("\\", "/");

modules/openapi-generator/src/test/resources/3_0/issue796.yaml

@@ -0,0 +1,37 @@
+openapi: 3.0.1
+info:
+  title: Issue 796
+  license:
+    name: Apache-2.0
+    url: http://www.apache.org/licenses/LICENSE-2.0.html
+  version: 1.0.0
+servers:
+- url: http://localhost:123/api
+paths:
+  /test:
+    get:
+      tags:
+      - test
+      responses:
+        201:
+          description: Successful response
+components:
+  schemas:
+    MapTest1:
+      type: object
+      description: This type example 1
+      additionalProperties: {}
+    MapTest2:
+      type: object
+      description: This type example 2
+      additionalProperties: true
+    MapTest3:
+      type: object
+      description: This type example 3
+      additionalProperties:
+        type: object
+    OtherObj:
+      type: object
+      description: This type example 4
+      additionalProperties: false
+