Add style and explode (#4042)

* Add parameter

* Set default value as Parameter.explode could be null

* Fix typo

* Add a link to the spec

* Add tests

* Delete unused import

* Rename: shouldExplode -> isExplode

* Include the new property

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

@@ -26,9 +26,9 @@ import java.util.Objects;
 public class CodegenParameter {
     public boolean isFormParam, isQueryParam, isPathParam, isHeaderParam,
             isCookieParam, isBodyParam, hasMore, isContainer,
-            secondaryParam, isCollectionFormatMulti, isPrimitiveType, isModel;
+            secondaryParam, isCollectionFormatMulti, isPrimitiveType, isModel, isExplode;
     public String baseName, paramName, dataType, datatypeWithEnum, dataFormat,
-            collectionFormat, description, unescapedDescription, baseType, defaultValue, enumName;
+            collectionFormat, description, unescapedDescription, baseType, defaultValue, enumName, style;
 
     public String example; // example value (x-example)
     public String jsonSchema;
@@ -173,6 +173,7 @@ public class CodegenParameter {
         output.isFreeFormObject = this.isFreeFormObject;
         output.isListContainer = this.isListContainer;
         output.isMapContainer = this.isMapContainer;
+        output.isExplode = this.isExplode;
 
         return output;
     }
@@ -247,7 +248,8 @@ public class CodegenParameter {
             Objects.equals(maxItems, that.maxItems) &&
             Objects.equals(minItems, that.minItems) &&
             Objects.equals(uniqueItems, that.uniqueItems) &&
-            Objects.equals(multipleOf, that.multipleOf);
+            Objects.equals(multipleOf, that.multipleOf) &&
+            Objects.equals(isExplode, that.isExplode);
     }
 
     @Override
@@ -316,7 +318,8 @@ public class CodegenParameter {
             maxItems,
             minItems,
             uniqueItems,
-            multipleOf);
+            multipleOf,
+            isExplode);
     }
 
     @java.lang.Override
@@ -386,6 +389,7 @@ public class CodegenParameter {
                 ", minItems=" + minItems +
                 ", uniqueItems=" + uniqueItems +
                 ", multipleOf=" + multipleOf +
+                ", isExplode=" + isExplode +
                 '}';
     }
 }

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

@@ -17,7 +17,6 @@
 
 package org.openapitools.codegen;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
 import com.google.common.base.CaseFormat;
 import com.google.common.collect.ImmutableMap;
 import com.samskivert.mustache.Mustache;
@@ -3099,7 +3098,15 @@ public class DefaultCodegen implements CodegenConfig {
             // set default value
             codegenParameter.defaultValue = toDefaultValue(parameterSchema);
 
-            // TDOO revise collectionFormat
+            if (parameter.getStyle() != null) {
+                codegenParameter.style = parameter.getStyle().toString();
+            }
+
+            // the default value is false
+            // https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#user-content-parameterexplode
+            codegenParameter.isExplode = parameter.getExplode() == null ? false : parameter.getExplode();
+
+            // TODO revise collectionFormat
             String collectionFormat = null;
             if (ModelUtils.isArraySchema(parameterSchema)) { // for array parameter
                 final ArraySchema arraySchema = (ArraySchema) parameterSchema;

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

@@ -27,7 +27,6 @@ import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.headers.Header;
 import io.swagger.v3.oas.models.media.*;
-import io.swagger.v3.oas.models.parameters.Parameter;
 import io.swagger.v3.oas.models.parameters.QueryParameter;
 import io.swagger.v3.oas.models.parameters.RequestBody;
 import io.swagger.v3.oas.models.responses.ApiResponse;
@@ -43,13 +42,11 @@ import org.openapitools.codegen.utils.ModelUtils;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
-import static org.testng.Assert.assertEquals;
-import static org.testng.Assert.assertNotNull;
-import static org.testng.Assert.assertTrue;
-
 import java.util.*;
 import java.util.stream.Collectors;
 
+import static org.testng.Assert.*;
+
 
 public class DefaultCodegenTest {
 
@@ -1003,4 +1000,35 @@ public class DefaultCodegenTest {
         assertEquals(codegen.toApiName(""), "DefaultApi");
     }
 
+    public static class FromParameter {
+        private CodegenParameter codegenParameter(String path) {
+            final OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/fromParameter.yaml");
+            new InlineModelResolver().flatten(openAPI);
+            final DefaultCodegen codegen = new DefaultCodegen();
+            codegen.setOpenAPI(openAPI);
+
+            return codegen
+                    .fromParameter(
+                            openAPI
+                                    .getPaths()
+                                    .get(path)
+                                    .getGet()
+                                    .getParameters()
+                                    .get(0),
+                            new HashSet<>()
+                    );
+        }
+
+        @Test
+        public void setStyle() {
+            CodegenParameter parameter = codegenParameter("/set_style");
+            assertEquals("form", parameter.style);
+        }
+
+        @Test
+        public void setShouldExplode() {
+            CodegenParameter parameter = codegenParameter("/set_should_explode");
+            assertTrue(parameter.isExplode);
+        }
+    }
 }

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

@@ -0,0 +1,35 @@
+openapi: 3.0.0
+servers:
+  - url: 'localhost:8080'
+info:
+  version: 1.0.0
+  title: OpenAPI Petstore
+  license:
+    name: Apache-2.0
+    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
+paths:
+  /set_style:
+    get:
+      operationId: setStyle
+      parameters:
+        - in: query
+          name: setStyleQuery
+          style: form
+          schema:
+            type: object
+            properties:
+              setStyleQueryParam:
+                type: string
+  /set_should_explode:
+    get:
+      operationId: setShouldExplode
+      parameters:
+        - in: query
+          name: setShouldExplodeQuery
+          style: form
+          explode: true
+          schema:
+            type: object
+            properties:
+              setShouldExplodeQueryParam:
+                type: string