[BUG] AsyncAPI generator for Java doesn't generate class correctly when there's reference to itself

[xespirit]

Describe the bug.

Modelina Async generator fails to generate Java class correctly in certain scenario: there's self-refence. Example:

{
  "asyncapi": "2.6.0",
  "info": {
    "title": "Case",
    "version": "1.0.0",
    "description": "AsyncAPI schema definition for Case"
  },
  "channels": {},
  "components": {
    "schemas": {
      "CaseSchema": {
        "$id": "CaseSchema",
        "type": "object",
        "properties": {
          "name": {
            "type": "string"
          },
          "label": {
            "type": "string"
          },
          "exceptForCase": {
            "type": "array",
            "items": {
              "type": "object",
              "$ref": "./Case.json#/components/schemas/CaseSchema"
            }
          }
        }
      }
    }
  }
}

Expected behavior

Generated Java class should have
private List<CaseSchema> exceptForCase;

instead it generates array of Map<String, Object>:

private List<Map<String, Object>> exceptForCase;

Screenshots

Example:

Generated class:

How to Reproduce

See screeshots above

🥦 Browser

None

👀 Have you checked for similar open issues?

• I checked and didn't find similar issue

🏢 Have you read the Contributing Guidelines?

• I have read the Contributing Guidelines

Are you willing to work on this issue ?

No, someone else can work on it

[github-actions]

Welcome to AsyncAPI. Thanks a lot for reporting your first issue. Please check out our contributors guide and the instructions about a basic recommended setup useful for opening a pull request.
Keep in mind there are also other channels you can use to interact with AsyncAPI community. For more details check out this issue.

[jonaslagoni]

Hey @xespirit, which version are you using?

I am pretty sure this is an old bug from Modelina v2

[jonaslagoni]

In v3 I get the following (https://modelina.org/playground?language=java):

{
  "asyncapi":"2.5.0",
  "info":{
     "title":"Streetlights API",
     "version":"1.0.0",
     "description":"The Smartylighting Streetlights API allows you\nto remotely manage the city lights.\n",
     "license":{
        "name":"Apache 2.0",
        "url":"https://www.apache.org/licenses/LICENSE-2.0"
     }
  },
  "servers":{
     "mosquitto":{
        "url":"mqtt://test.mosquitto.org",
        "protocol":"mqtt"
     }
  },
  "channels":{
     "lightmeasured":{
        "publish":{
           "summary":"Inform about environmental lighting conditions for a particular streetlight.",
           "operationId":"onLightMeasured",
           "message":{
              "name":"LightMeasured",
              "payload":{
                 "$id": "CaseSchema",
                 "type":"object",
                 "properties":{
                    "name":{
                       "type":"string"
                    },
                    "label":{
                       "type":"string"
                    },
                    "exceptForCase":{
                       "type":"array",
                       "items":{
                          "$ref":"#/channels/lightmeasured/publish/message/payload"
                       }
                    }
                 }
              }
           }
        }
     }
  }
}

package asyncapi.models;

import java.util.Map;
public class CaseSchema {
  private String name;
  private String label;
  private CaseSchema[] exceptForCase;
  private Map<String, Object> additionalProperties;

  public String getName() { return this.name; }
  public void setName(String name) { this.name = name; }

  public String getLabel() { return this.label; }
  public void setLabel(String label) { this.label = label; }

  public CaseSchema[] getExceptForCase() { return this.exceptForCase; }
  public void setExceptForCase(CaseSchema[] exceptForCase) { this.exceptForCase = exceptForCase; }

  public Map<String, Object> getAdditionalProperties() { return this.additionalProperties; }
  public void setAdditionalProperties(Map<String, Object> additionalProperties) { this.additionalProperties = additionalProperties; }
}

[xespirit]

Hey @xespirit, which version are you using?

I am pretty sure this is an old bug from Modelina v2

I use 4.0.0-next.16 version of modelina:

"dependencies": {
    "@asyncapi/modelina": "^4.0.0-next.16",
    "ts-node": "^10.9.2",
    "typescript": "4.9.5"
  },

[jonaslagoni]

Ehh. Let me take a look with next 🤔

[jonaslagoni]

@xespirit even with next when I use the following AsyncAPI document it works fine (https://65f02a20166dac9eadcc846e--modelina.netlify.app/playground?language=java):

{
  "asyncapi":"2.5.0",
  "info":{
     "title":"Streetlights API",
     "version":"1.0.0",
     "description":"The Smartylighting Streetlights API allows you\nto remotely manage the city lights.\n",
     "license":{
        "name":"Apache 2.0",
        "url":"https://www.apache.org/licenses/LICENSE-2.0"
     }
  },
  "servers":{
     "mosquitto":{
        "url":"mqtt://test.mosquitto.org",
        "protocol":"mqtt"
     }
  },
  "channels":{
     "lightmeasured":{
        "publish":{
           "summary":"Inform about environmental lighting conditions for a particular streetlight.",
           "operationId":"onLightMeasured",
           "message":{
              "name":"LightMeasured",
              "payload":{
                 "$id": "CaseSchema",
                 "type":"object",
                 "properties":{
                    "name":{
                       "type":"string"
                    },
                    "label":{
                       "type":"string"
                    },
                    "exceptForCase":{
                       "type":"array",
                       "items":{
                          "$ref":"#/channels/lightmeasured/publish/message/payload"
                       }
                    }
                 }
              }
           }
        }
     }
  }
}

Might have something to do with your $ref pointing to the file itself 🤔 Is there a more complex setup in place that might cause this?

[xespirit]

@xespirit even with next when I use the following AsyncAPI document it works fine (https://65f02a20166dac9eadcc846e--modelina.netlify.app/playground?language=java):

{
  "asyncapi":"2.5.0",
  "info":{
     "title":"Streetlights API",
     "version":"1.0.0",
     "description":"The Smartylighting Streetlights API allows you\nto remotely manage the city lights.\n",
     "license":{
        "name":"Apache 2.0",
        "url":"https://www.apache.org/licenses/LICENSE-2.0"
     }
  },
  "servers":{
     "mosquitto":{
        "url":"mqtt://test.mosquitto.org",
        "protocol":"mqtt"
     }
  },
  "channels":{
     "lightmeasured":{
        "publish":{
           "summary":"Inform about environmental lighting conditions for a particular streetlight.",
           "operationId":"onLightMeasured",
           "message":{
              "name":"LightMeasured",
              "payload":{
                 "$id": "CaseSchema",
                 "type":"object",
                 "properties":{
                    "name":{
                       "type":"string"
                    },
                    "label":{
                       "type":"string"
                    },
                    "exceptForCase":{
                       "type":"array",
                       "items":{
                          "$ref":"#/channels/lightmeasured/publish/message/payload"
                       }
                    }
                 }
              }
           }
        }
     }
  }
}

Might have something to do with your $ref pointing to the file itself 🤔 Is there a more complex setup in place that might cause this?

Yes, it has something to do with $ref pointing to itself. There's no any complex setup. I have tried Modelina generator with different json schemas, with different complexity. Everything works well except for case I mentioned above.

Is there any default behaviour of generator so It gneerates Map<String, Object> witjhout even including Java import for Map. My guess it happens when the generator gets confused so it somehow generates the map instead of correct object type.

[jonaslagoni]

Damn, yea thats a bug!

modelina/src/generators/java/JavaConstrainer.ts

Line 238 in 1239c9a

return `Map<${constrainedModel.key.type}, ${constrainedModel.value.type}>`;

We need to add the dependency import like we do for Python here:

modelina/src/generators/python/PythonConstrainer.ts

Line 20 in 1239c9a

dependencyManager.addDependency('from typing import Any');

Do you mind helping to fix this?

[xespirit]

Damn, yea thats a bug!

modelina/src/generators/java/JavaConstrainer.ts

Line 238 in 1239c9a

return `Map<${constrainedModel.key.type}, ${constrainedModel.value.type}>`;

We need to add the dependency import like we do for Python here:

modelina/src/generators/python/PythonConstrainer.ts

Line 20 in 1239c9a

dependencyManager.addDependency('from typing import Any');

Do you mind helping to fix this?

I'm sorry but I'm Java/Kotlin Back-end developer, I don't think I have capacity right now to fix Typescript codebase

[jonaslagoni]

No worries, created a good first issue for it: #1892

Yes, it has something to do with $ref pointing to itself. There's no any complex setup. I have tried Modelina generator with different json schemas, with different complexity. Everything works well except for case I mentioned above.

Regarding this problem, I simply cant reproduce your problem, unfortunately... Cause the example you gave generates the correct models.

Can you reproduce it yourself on the playground and post the example? https://65f02a20166dac9eadcc846e--modelina.netlify.app/playground?language=java

[AKACHI-4]

Hey @jonaslagoni I would love to work on it.

However, Same stands for me as well; I am also unable to generate this problem in playground, I am still wondering why that

---

If the Change is this only, then why only this specific case isn't importing map. It's weird.

{
  "asyncapi": "2.6.0",
  "info": {
    "title": "Case",
    "version": "1.0.0",
    "description": "AsyncAPI schema definition for Case"
  },
  "channels": {},
  "components": {
    "schemas": {
      "CaseSchema": {
        "$id": "CaseSchema",
        "type": "object",
        "properties": {
          "name": {
            "type": "string"
          },
          "label": {
            "type": "string"
          },
          "exceptForCase": {
            "type": "array",
            "items": {
              "type": "object",
              "$ref": "#/components/schemas/CaseSchema"
            }
          }
        }
      }
    }
  }
}

[jonaslagoni]

If the Change is this only, then why only this specific case isn't importing map. It's weird.

It's for every case, where there is a dictionary model 🙂

[xespirit]

@xespirit even with next when I use the following AsyncAPI document it works fine (https://65f02a20166dac9eadcc846e--modelina.netlify.app/playground?language=java):

{
  "asyncapi":"2.5.0",
  "info":{
     "title":"Streetlights API",
     "version":"1.0.0",
     "description":"The Smartylighting Streetlights API allows you\nto remotely manage the city lights.\n",
     "license":{
        "name":"Apache 2.0",
        "url":"https://www.apache.org/licenses/LICENSE-2.0"
     }
  },
  "servers":{
     "mosquitto":{
        "url":"mqtt://test.mosquitto.org",
        "protocol":"mqtt"
     }
  },
  "channels":{
     "lightmeasured":{
        "publish":{
           "summary":"Inform about environmental lighting conditions for a particular streetlight.",
           "operationId":"onLightMeasured",
           "message":{
              "name":"LightMeasured",
              "payload":{
                 "$id": "CaseSchema",
                 "type":"object",
                 "properties":{
                    "name":{
                       "type":"string"
                    },
                    "label":{
                       "type":"string"
                    },
                    "exceptForCase":{
                       "type":"array",
                       "items":{
                          "$ref":"#/channels/lightmeasured/publish/message/payload"
                       }
                    }
                 }
              }
           }
        }
     }
  }
}

Might have something to do with your $ref pointing to the file itself 🤔 Is there a more complex setup in place that might cause this?

I'm providing full sets of files to reproduce the issue:

Case.json
DirectPolicy.json
Insurance.json
Policy.json
Schemas.json

The generator is being called from Maven plug-in:

generate
./node_modules/.bin/ts-node ./generate.ts com.test.asyncapi.model model/Schemas.json target/generated-sources/asyncapi/com/test/asyncapi/model

I've attached pictures of generated files, representing the issue below:

@jonaslagoni could you try to reproduce the bug?

As you can see Modelina generator thinks all files are generated successfuly (without exiting with error). But in fact we have:

@JsonProperty("exceptForCase")
@JsonInclude(JsonInclude.Include.NON_NULL)
private List<Map<String, Object>> exceptForCase;

and exceptForCase shouldn't be a list of Map<String, Object>. Expected result is a

private List<CaseSchema> exceptForCase;

[jonaslagoni]

Just pinging that I have not forgotten about this, but have to work on some other fixes that I think will fix this along side it.