Add nullable support

Author: RolandHewage

asyncapi-cli/src/main/java/io/ballerina/asyncapi/codegenerator/usecase/GenerateModuleMemberDeclarationNode.java

@@ -19,6 +19,7 @@
 package io.ballerina.asyncapi.codegenerator.usecase;
 
 import com.fasterxml.jackson.databind.node.TextNode;
+import io.apicurio.datamodels.core.models.Extension;
 import io.ballerina.asyncapi.codegenerator.configuration.BallerinaAsyncApiException;
 import io.ballerina.asyncapi.codegenerator.configuration.Constants;
 import io.ballerina.asyncapi.codegenerator.entity.Schema;
@@ -177,12 +178,14 @@ private void addRecordField(List<String> required, List<Node> recordFieldList, M
     private TypeDescriptorNode getTypeDescriptorNode(Schema schema)
             throws BallerinaAsyncApiException {
         if (schema.getType() != null || schema.getSchemaProperties() != null) {
-            return getTypeDescriptorNodeForObjects(schema);
+            TypeDescriptorNode originalTypeDesc = getTypeDescriptorNodeForObjects(schema);
+            return addNullableType(schema, originalTypeDesc);
         } else if (schema.getRef() != null) {
             String type = codegenUtils.extractReferenceType(schema.getRef());
             type = codegenUtils.getValidName(type, true);
             Token typeName = AbstractNodeFactory.createIdentifierToken(type);
-            return createBuiltinSimpleNameReferenceNode(null, typeName);
+            TypeDescriptorNode originalTypeDesc = createBuiltinSimpleNameReferenceNode(null, typeName);
+            return addNullableType(schema, originalTypeDesc);
         } else {
             // This contains a fallback to Ballerina common type `anydata` if the Async Api specification type is not
             // defined.
@@ -329,4 +332,13 @@ public TypeDescriptorNode getTypeDescriptorNodeForArraySchema(Schema schema) thr
         }
     }
 
+    private TypeDescriptorNode addNullableType(Schema schema, TypeDescriptorNode originalTypeDesc) {
+        if (schema.getExtension("x-nullable") != null) {
+            Extension identifier = (Extension) schema.getExtension("x-nullable");
+            if (identifier.value.equals(true)) {
+                return createOptionalTypeDescriptorNode(originalTypeDesc, createToken(QUESTION_MARK_TOKEN));
+            }
+        }
+        return originalTypeDesc;
+    }
 }

asyncapi-cli/src/test/java/io/ballerina/asyncapi/codegenerator/usecase/GenerateModuleMemberDeclarationNodeTest.java

@@ -171,4 +171,62 @@ public void testGenerateWithInvalidNumberFormat() throws BallerinaAsyncApiExcept
         Generator generateRecordNode = new GenerateModuleMemberDeclarationNode(entry);
         generateRecordNode.generate();
     }
+
+    @Test(description = "Test the functionality of the generate function " +
+            "when there are nullable fields in the schema")
+    public void testGenerateWithNullables() throws BallerinaAsyncApiException {
+        String asyncApiSpecStr = fileRepository
+                .getFileContentFromResources("specs/spec-single-schema-with-x-nullable.yml");
+        String asyncApiSpecJson = fileRepository.convertYamlToJson(asyncApiSpecStr);
+        AaiDocument asyncApiSpec = (Aai20Document) Library.readDocumentFromJSONString(asyncApiSpecJson);
+        Extractor extractSchemasFromSpec = new ExtractSchemasFromSpec(asyncApiSpec);
+        Map<String, Schema> schemas = extractSchemasFromSpec.extract();
+
+        Iterator<Map.Entry<String, Schema>> iterator = schemas.entrySet().iterator();
+        Map.Entry<String, Schema> firstEntry = iterator.next();
+        Generator generateRecordNode1 = new GenerateModuleMemberDeclarationNode(firstEntry);
+        TypeDefinitionNode typeDefinitionNode1 = generateRecordNode1.generate();
+        Assert.assertEquals(typeDefinitionNode1.typeName().text(), "TotalPriceSet");
+
+        Map.Entry<String, Schema> secondEntry = iterator.next();
+        Generator generateRecordNode2 = new GenerateModuleMemberDeclarationNode(secondEntry);
+        TypeDefinitionNode typeDefinitionNode2 = generateRecordNode2.generate();
+        Assert.assertEquals(typeDefinitionNode2.typeName().text(), "Price");
+
+        Map.Entry<String, Schema> thirdEntry = iterator.next();
+        Generator generateRecordNode3 = new GenerateModuleMemberDeclarationNode(thirdEntry);
+        TypeDefinitionNode typeDefinitionNode3 = generateRecordNode3.generate();
+        Assert.assertEquals(typeDefinitionNode3.typeName().text(), "OrderEvent");
+
+        Map.Entry<String, Schema> forthEntry = iterator.next();
+        Generator generateRecordNode4 = new GenerateModuleMemberDeclarationNode(forthEntry);
+        TypeDefinitionNode typeDefinitionNode4 = generateRecordNode4.generate();
+        Assert.assertEquals(typeDefinitionNode4.typeName().text(), "TaxLine");
+
+        Assert.assertTrue(typeDefinitionNode3.typeDescriptor() instanceof RecordTypeDescriptorNode);
+        RecordTypeDescriptorNode recordTypeDescriptorNode3 =
+                (RecordTypeDescriptorNode) typeDefinitionNode3.typeDescriptor();
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(0)).typeName().toSourceCode(),
+                "TotalPriceSet?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(1)).typeName().toSourceCode(),
+                "TaxLine[]?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(2)).typeName().toSourceCode(),
+                "decimal?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(3)).typeName().toSourceCode(),
+                "record { Priceshop_money?;Price?presentment_money?;} ?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(4)).typeName().toSourceCode(),
+                "int?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(5)).typeName().toSourceCode(),
+                "boolean?");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode3.fields().get(6)).typeName().toSourceCode(),
+                "string?");
+
+        Assert.assertTrue(typeDefinitionNode4.typeDescriptor() instanceof RecordTypeDescriptorNode);
+        RecordTypeDescriptorNode recordTypeDescriptorNode4 =
+                (RecordTypeDescriptorNode) typeDefinitionNode4.typeDescriptor();
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode4.fields().get(2)).typeName().toSourceCode(),
+                "string");
+        Assert.assertEquals(((RecordFieldNode) recordTypeDescriptorNode4.fields().get(3)).typeName().toSourceCode(),
+                "string?");
+    }
 }

asyncapi-cli/src/test/resources/specs/spec-single-schema-with-x-nullable.yml

@@ -0,0 +1,77 @@
+asyncapi: 2.1.0
+components:
+  schemas:
+    OrderEvent:
+      properties:
+        id:
+          type: integer
+          description: The ID of the order, used for API purposes. This is different from the order_number property, which is the ID used by the shop owner and customer.
+          x-nullable: true
+        email:
+          type: string
+          description: The customer's email address.
+          x-nullable: true
+        confirmed:
+          type: boolean
+          description: Confirmation status
+          x-nullable: true
+        rate:
+          type: number
+          description: The rate of tax to be applied.
+          x-nullable: true
+        tax_lines:
+          type: array
+          items:
+            $ref: '#/components/schemas/TaxLine'
+          description: An array of tax line objects, each of which details a tax applicable to the order. When creating an order through the API, tax lines can be specified on the order or the line items but not both. Tax lines specified on the order are split across the taxable line items in the created order.
+          x-nullable: true
+        total_price_set:
+          $ref: '#/components/schemas/TotalPriceSet'
+          x-nullable: true
+        total_tax_set:
+          type: object
+          properties:
+            shop_money:
+              $ref: '#/components/schemas/Price'
+            presentment_money:
+              $ref: '#/components/schemas/Price'
+              x-nullable: true
+          description: The total tax applied to the order in shop and presentment currencies.
+          x-nullable: true
+    TaxLine:
+      type: object
+      properties:
+        price:
+          type: string
+          description: The amount of tax to be charged in the shop currency.
+          x-nullable: false
+        rate:
+          type: number
+          description: The rate of tax to be applied.
+        title:
+          type: string
+          description: The name of the tax.
+          x-nullable: true
+        channel_liable:
+          type: boolean
+          description: Whether the channel that submitted the tax line is liable for remitting. A value of null indicates unknown liability for the tax line.
+      description: Tax line object, which details a tax applicable to the order.
+    TotalPriceSet:
+      type: object
+      properties:
+        shop_money:
+          $ref: '#/components/schemas/Price'
+        presentment_money:
+          $ref: '#/components/schemas/Price'
+      description: The total price of the order in shop and presentment currencies.
+    Price:
+      type: object
+      properties:
+        amount:
+          type: string
+          description: The variant's price or compare-at price in the presentment currency.
+        currency_code:
+          type: string
+          description: The three-letter code (ISO 4217 format) for one of the shop's enabled presentment currencies.
+          x-nullable: true
+      description: The price object