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openapi schema object to json object

I am working on an endpoint implementation that wraps multiple endpoints.
There is an endpoint /entity1 implemented in a dependency with its own openapi spec generated in maven plugin to a certain package. And there is an endpoint /entity2 which comes from another dependency.
I am trying to generate a spec for /batch gets an array of entity1 and an array of entity2, like this schema:
paths:
/batch:
post:
description: Batch ingest data
operationId: batchCreate
requestBody:
content:
application/json:
schema:
$ref: '#/components/schemas/Batch'
description: ...
components:
schemas:
Batch:
type: object
properties:
entity1list:
type: array
items:
type: object
entity2list:
type: array
items:
type: object
I currently have the model generated with java plain Object.
Questions:
Is it possible to point the openapi to a different spec loaded in a different package? That would be ideal. Keep in mind I can't import the spec and regenerate the code since it won't do it on different packages.
If not, can I convert the plain Object to Entity1/Entity2?

Solved using the post #Cristian referred to. While generating, it is possible to map certain references. Documentation here
<plugin>
<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>${openapi-generator-maven-plugin.version}</version>
<configuration>
... excluded for simplicity
<importMappings>
<importMapping>SignatureNotification=path.to.your.SignatureNotification</importMapping>
</importMappings>
</configuration>
</plugin>

Generating POJOs using OpenAPI generator with Lombok Annotations

I am using OpenAPI generator maven plugin like one below for generating Java client code for models .
<plugin>
<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>4.3.1</version>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
<configuration>
<inputSpec>${project.basedir}/src/main/resources/api.yaml</inputSpec>
<generatorName>java</generatorName>
<configOptions>
<sourceFolder>src/gen/java/main</sourceFolder>
</configOptions>
</configuration>
</execution>
</executions>
</plugin>
When , I generate the model classes, they get generated with usual POJO field declarations and getters and setters. But what I want to do is, instead of generating getters and setters, I want my classes to get automatically generated with Lombok annotations for Java pojos like #Getter, #Setter, #Data, etc. Is there a way to customize model generator to fit above use case requirement?
I tried to find out if there is a way. I found this discussion, where the very last comment talks about a PR, where the issue of generating models using Lombok annotations has been addressed. But I do not see any clear indication of usage or any documentation of this feature in the OpenAPI generator open source project that it has been implemented yet. So, is there any way of generating models with Lombok annotations instead of regular getters and setters today?

To complete this very old thread: Now it does support Lombok annotations.
Example taken from here
<configOptions>
<additionalModelTypeAnnotations>#lombok.Builder #lombok.NoArgsConstructor #lombok.AllArgsConstructor</additionalModelTypeAnnotations>
</configOptions>

EDIT: This answer is deprecated. See the post by #Laess3r. I'll leave this, since it is applicable for older versions of openapi generator.
openapi-generator does not yet support Lombok annotations. If you want to generate code with Lombok annotations, you need to create a custom template in mustache, as described in https://openapi-generator.tech/docs/templating/.
If you've never worked with mustache, be aware that it's somewhat hard to read, so try to keep the templates as simple as possible and make sure to add unit tests to validate the generated output. The template will look something like this:
/**
* {{#description}}{{description}}{{/description}}
*/
#Data
public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}} {
{{#vars}}
/**
* {{#description}}{{description}}{{/description}}
*/
#JsonProperty("{{#lambda.lowercase}}{{nameInSnakeCase}}{{/lambda.lowercase}}")
private {{{datatypeWithEnum}}} {{name}};
{{/vars}}

I've been able to get this working out-of-the-box using a space
separated list of annotations on models:
#lombok.experimental.SuperBuilder #lombok.external.Jacksonized
If models have readOnly set to "true" the Builder becomes the only way to make the object and #Jacksonized allows it to be serialized/deserialized. There are some limitations with inheritance (turning off requiring all required parameters in the configOptions).

How to generate Swagger codegen Java models as JPA Entities

I am using Swagger codegen to create Java models to be used in a Spring REST server, and would like to know how to get Swagger to declare each model as a JPA entity.
I generate the code with the swagger-codegen-maven-plugin as follows:
<plugin>
<groupId>io.swagger</groupId>
<artifactId>swagger-codegen-maven-plugin</artifactId>
<version>2.4.0</version>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
<configuration>
<inputSpec>${project.basedir}/src/main/openApi/Rack.json</inputSpec>
<language>spring</language>
<groupId>com.me</groupId>
<artifactId>rest-server</artifactId>
<apiPackage>com.me.rest.api</apiPackage>
<modelPackage>com.me.rest.model</modelPackage>
<invokerPackage>com.me.rest.invoker</invokerPackage>
<configOptions>
<sourceFolder>src/gen/java/main</sourceFolder>
<java8>true</java8>
<dateLibrary>java8</dateLibrary>
</configOptions>
</configuration>
</execution>
</executions>
</plugin>
As I have it now, this is the abbreviated java code that gets generated:
#Validated
#javax.annotation.Generated(value = "io.swagger.codegen.languages.SpringCodegen", date = "...")
public class Rack {
#JsonProperty("id")
private Long id = null;
#JsonProperty("name")
private String name = null;
...
}
How do I get Swagger to add the #Entity and #Id JPA annotations, as follows?
import javax.persistence.Entity;
import javax.persistence.Id;
#Entity
#Validated
#javax.annotation.Generated(value = "io.swagger.codegen.languages.SpringCodegen", date = "...")
public class Rack {
#Id
#JsonProperty("id")
private Long id = null;
#JsonProperty("name")
private String name = null;
...
}
This way, all I would have to do to get Spring to automatically expose these generated classes as REST APIs, would be to add the following to my pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
Then I could create the JPA repositories with Spring-Data, as follows:
public interface RackRepository extends CrudRepository<Rack, Long> {
}

A PR has recently been merged fixing your issue : https://github.com/OpenAPITools/openapi-generator/pull/11775
You need to upgrade your Maven plugin to use the latest version (currently unreleased, only snapshot is available)
<plugin>
<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>6.0.0-SNAPSHOT</version>
...
</plugin>
The configuration might be slightly different.
Then you need to add x-class-extra-annotation and x-field-extra-annotation in your spec.
For instance for the Pet Clinic:
schemas:
Pet:
type: object
x-class-extra-annotation: "#javax.persistence.Entity"
required:
- id
- name
properties:
id:
type: integer
format: int64
x-field-extra-annotation: "#javax.persistence.Id"
name:
type: string
tag:
type: string

While the right way to solve this surely is an extension of swagger-codegen (probably with the introduction of some kind of include/exclude config), I got away with a fairly simply post-processing of the generated files.
In contrast to the OP I use Gradle instead of Maven and leveraged its extended filtering functionality. For Maven it is probably necessary to run a Groovy-script by way of the Groovy-Maven-Plugin, since Maven only supports placeholder substitution (as does Ant, so using the AntRun-Plugin would also not work).
I used a simple heuristic to only include entities with an id - the logic is as follows:
for all Java-files containing an ID-field
include import statement for javax.persistence.* after the package declaration
add the #Entity-annotation before the class definition
for the ID-field, add the annotations #Id and #GeneratedValue
(based on field names, other annotations - #OneToMany etc. - may be added as well)
Gradle-users may find the following task useful as a start:
task generateJpaAnnotations(type: Copy) {
from "${swaggerSources.<modelName>.code.outputDir}/src/main/java"
into "<output dir>
include '**/*.java'
eachFile {
if (it.file.text.contains("private Long id")) {
filter { line -> line.contains('package') ? "$line\nimport javax.persistence.*;" : line }
filter { line -> line.contains('public class') ? "#Entity\n$line" : line }
filter { line -> line.contains('private Long id') ? "#Id\n#GeneratedValue(strategy=GenerationType.AUTO)\n$line" : line } }
}
}

So I'm actually asking myself the same question.
I found an example but the guy is simply re-defining his POJOs and providing a way to adapt the generated ones to the handwritten ones. Tedious and not evolutive.
Globally this could be hard because I'm not sure there is a way in your swagger to decide which POJO will be JPA enabled and maybe you don't want them all in your DB (?) Also, how to you tag the id in swagger?
If you know of such a way, you can always modify the mustache (pojo.mustache I guess) to give you the annotations you're missing.

Olingo - Create strongly typed POJOs for client library of OData service

I'm using Apache Olingo as an OData client for a Java SDK that I will provide for a RESTful OData API. In the SDK I want to be able to have strongly typed classes to represent the OData entities. I'm having trouble implementing this easily and thus feel like I'm missing a different strategy here.
The Olingo way seems to be to get an ODataClient object which provides the user with a bunch of useful methods for interacting with the API. The ODataClient is using a bunch of factory methods to build my request. For instance, this is the code I used to get the Customers from the Northwind sample OData service. client is an an instance of the necessary ODataClient class.
String serviceRoot = "http://services.odata.org/V4/Northwind/Northwind.svc";
URI customersUri = client.newURIBuilder(serviceRoot)
.appendEntitySetSegment("Customers").build();
ODataRetrieveResponse<ODataEntitySetIterator<ODataEntitySet, ODataEntity>> response =
client.getRetrieveRequestFactory().getEntitySetIteratorRequest(customersUri).execute();
if (response.getStatusCode() >= 400) {
log("Error");
return;
}
ODataEntitySetIterator<ODataEntitySet, ODataEntity> iterator = response.getBody();
while (iterator.hasNext()) {
ODataEntity customer = iterator.next();
log(customer.getId().toString());
}
I'd like to end up with a strongly typed entity from the iterator (i.e. Customer customer = iterator.next()). However, I'm not sure how to actually do that.
If I create a Customer class that extends ODataEntity and attempt to perform a cast such as Customer customer = (Customer) iterator.next() then I get a ClassCastException since the objects in the iterator are just ODataEntity objects and know nothing about the Customer subclass.
My next thought was to introduce generics but doing so will require what seems like a good amount of modification to the Olingo library which leads me to think that there is a better way to do this.
I'm using the development version of Apache Olingo 4 since the OData service must use OData 4.
What am I missing?

It is not really advertised, but there is nowadays a POJO generator in Olingo, in the source tree at ext / pojogen-maven-plugin. Unfortunately for using the POJOs another layer with a different programming model is added, which holds entities cached in memory and syncs with OData service on a flush operation. I would be really interested in adapting it to a more conventional request/response model based on Olingos Request Factories.
However, you could try it out. In your pom include pojogen-maven-plugin and odata-client-proxy.
The POJO generation can be triggered in the pom with
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.8</version>
<executions>
<execution>
<phase>process-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.olingo</groupId>
<artifactId>pojogen-maven-plugin</artifactId>
<version>4.2.0-SNAPSHOT</version>
<configuration>
<outputDirectory>${project.build.directory}/generated-sources</outputDirectory>
<localEdm>${basedir}/src/main/resources/metadata.xml</localEdm>
<basePackage>odata.test.pojo</basePackage>
</configuration>
<executions>
<execution>
<id>v4pojoGen</id>
<phase>generate-sources</phase>
<goals>
<goal>v4pojoGen</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
For the experiment I stored the EDM Metadataof the Olingo Car example service at src/main/resources/metadata.xml. Somehow the plugin wants to create an inbetween ojc-plugin folder and I just moved the generated Java code at the proper place manually.
At that point you have a Service.java and Java interfaces for each entity or complex type in the EDM model.
You can make use of it to read some entities like this
Service<EdmEnabledODataClient> service = odata.test.pojo.Service.getV4("http://localhost:9080/odata-server-sample/cars.svc");
Container container = service.getEntityContainer(Container.class);
for (Manufacturer m : container.getManufacturers()) {
System.out.println(m.getName());
}

How to use JPA Criteria API when joining many tables

This is the further question to this:
How to use JPA Criteria API in JOIN
CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Company> criteria = criteriaBuilder.createQuery( Company.class );
Root<Company> companyRoot = criteria.from( Company.class );
Join<Company,Product> products = companyRoot.join("dentist");
Join<Company, City> cityJoin = companyRoot.join("address.city");//Company->Address->City-city
criteria.where(criteriaBuilder.equal(products.get("category"), "dentist"),      criteriaBuilder.equal(cityJoin.get("city"),"Leeds"));
A company has an address, inside the address there is City-pojo and Country-Pojo. How can I use it in JOIN? I tried to reference it with address.city but I got the error message:
The attribute [address.city] from the managed type
[EntityTypeImpl#1692700229:Company [ javaType: class
com.test.domain.Company descriptor:
RelationalDescriptor(com.test.domain.Company -->
[DatabaseTable(COMPANY)]), mappings: 16]] is not present.

If you use canonical Metamodel, you'll avoid this kind of errors.
In your code you have misused the "dentist" keyword, that's probably the cause of your error, because "dentist" is not a field in Company entity.
However, looking at how you defined your class in the other question, the way to define that join using Metamodel is this:
SetJoin<Company,Product> products = companyRoot.join(Company_.products);
As you can see, Metamodel avoids the use of strings, and so avoids a lot of runtime errors. If anyway you don't use Metamodel, try this:
SetJoin<Company,Product> products = companyRoot.join("products");
If you now want to add a predicate, i.e. something after the where, you'll write something like:
Predicate predicate = criteriaBuilder.equal(products.get(Product_.category), "dentist");
criteria.where(predicate);
If you want to add a join for the City entity:
Join<Company, City> city = companyRoot.join(Company_.city);
predicate = criteriaBuilder.and(predicate, criteriaBuilder.equal(city.get(City_.cityName), "Leeds");
criteria.where(predicate);
(supposing that the field cityName is the correct field name for your city).

Agree with #perissf.
I can't comment but the symbol "Company_" is the metadata class file which contains all the attribute name of the model class.
I strongly suggest to use metadata classes, you can autogenerate metadata classes using the maven processor plugin using org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor as processor in your configuration.
This example pom plugin xml should work it out :
<plugin>
<groupId>org.bsc.maven</groupId>
<artifactId>maven-processor-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>process</goal>
</goals>
<phase>generate-sources</phase>
<configuration>
<processors>
<processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
</processors>
</configuration>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.hibernate.orm</groupId>
<artifactId>hibernate-jpamodelgen</artifactId>
<version>${version.hibernate-jpamodelgen}</version>
</dependency>
</dependencies>
</plugin>