[Java] codegen with parcelableMode fails to build if using arrays in swagger

[morriscodes]

Description

Java codegen with parcelableMode enabled causing build errors if the swagger file has arrays.

Swagger-codegen version

snapshot 2.2.2

Swagger declaration file content or url

This is an example of how I create the array:

    {
    "WeatherValueTypes": {
        "type": "array",
        "items": {
        "type": "string",
         "enum": [
              "airTemp"
          ]
       }
    }

Command line used for generation

java -jar swagger-codegen-cli.jar generate -i swagger.json -l java -c config.json -o data

{
"artifactId": "Data",
  "artifactVersion": "1.0.0",
  "library": "retrofit2",
  "parcelableModel": true,
  "hideGenerationTimestamp": true
}

Steps to reproduce

command line generation works fine. It fails when you try to build from gradle.

Error Output

/git/swagger/data/src/main/java/com/test/data/model/WeatherValueTypes.java:66: error: cannot find symbol
     super.writeToParcel(out, flags);    }
          ^
  symbol: method writeToParcel(Parcel,int)
/git/swagger/data/src/main/java/com/test/data/model/WeatherValueTypes.java:73: error: no suitable constructor found for ArrayList(Parcel)
     super(in); 
     ^
    constructor ArrayList.ArrayList(int) is not applicable
      (argument mismatch; Parcel cannot be converted to int)
    constructor ArrayList.ArrayList(Collection<? extends String>) is not applicable
      (argument mismatch; Parcel cannot be converted to Collection<? extends String>)

Related issues

Suggest a Fix

This is the PR that added parcelable support:

https://github.com/swagger-api/swagger-codegen/pull/3320/files

{{#parent}} super(in); {{/parent}} and {{#parent}} super.writeToParcel(out, flags); {{/parent}} seem to be the primary issues when dealing with arrays.

[wing328]

@morriscodes thanks for reporting the issue.

What would be the correct code looks like for handling array of string?

[morriscodes]

The implementation of Parcelable needs to be further thought out. My example above is easily reproducible but the problem applies to any arrays.

Example:

"Wallet": {
    "type": "array",
    "items": {
        "$ref": "#\/definitions\/Money"
    }
 }

Swagger generates objects like this as extends ArrayList<Money> but when the Parcelable code is generated it checks for a parent, and if exists delegate the parcelable work up {{#parent}} super(in); {{/parent}}. This would work if the object extended Money and Money implements Parcelable but it doesn't, it extends ArrayList. ArrayList doesn't implement parcelable so your build fails.

Here is a stackoverflow example for handling parcelable on objects that extend ArrayList:
http://stackoverflow.com/questions/10953121/android-arraylistmyobject-pass-as-parcelable

As for the specific example of implementing parcelable on an object that extends ArrayList<String>.. as far as I can tell, you shouldn't. Parcelable has specific methods for handling String Lists. So if an object contains a property that is an ArrayList<String> you would implement that with writeStringList(List<String> val) and readStringList(List<String> list).

I'm no parcelable expert, the above is just what I discovered reading the docs this morning. Hopefully there are some stronger Mustache guys around that understand the correct way to implement something like this for swagger.

[wing328]

@morriscodes thanks for sharing more with me.

Just to confirm, is WeatherValueTypes a model/object or property of a model/object?

[morriscodes]

@wing328 Swagger generates it as its own model.

[wing328]

To define an array of model, you can define something like https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/test/resources/2_0/petstore.yaml#L112-L117

Would that help?

In other words, I want to avoid defining something like the following:

"Wallet": {
    "type": "array",
    "items": {
        "$ref": "#\/definitions\/Money"
    }
 }

[morriscodes]

@wing328 That would produce a better structure. I don't have access to change my swagger file but I will see if I can get my server team to update. Are there docs on creating arrays in this way that I can point them to?

[wing328]

@morriscodes the official OpenAPI 2.0 spec can be found in https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md

petstore.yaml is also a good starting point to understand how array of properties or models is defined.