JCodeModel: Attributes and Lists with special class-types

Question

I started to work with the JCodeModel today. I want to add Attributes with other types than int, String, boolean etc. to my JDefinedClass. The final Java Code built by the JCodeModel should look like:

public Class Team {
    private int teamID;
    private String teamName;
    private Coach coach;
}

How can I add the Field coach with the class type "Coach" with the JCodeModel?

jClass.field(JMod.PRIVATE, *???*, coach);

The second question is: How do I add e.g.

ArrayList<Coach> coachList;

to my attribute List? Thanks

Answer 1

You can simply generate the Coach class, and pass it as a parameter to the field(...) method. Note that this method accepts a JType as the second parameter, and JClass as well as JDefinedClass are both inheriting from JType.

For the ArrayList, you can define the type parameter by calling narrow on the defined class, passing in another JType. (This even works for type parameters - that is, you can even call c.narrow(cm.ref("T")) to give it a type parameter called T).

Here is an example:

import java.io.File;
import java.util.ArrayList;

import com.sun.codemodel.JClass;
import com.sun.codemodel.JCodeModel;
import com.sun.codemodel.JDefinedClass;
import com.sun.codemodel.JMod;


public class CodeModelTest
{
    public static void main(String[] args) throws Exception
    {
        JCodeModel codeModel = new JCodeModel();


        JDefinedClass teamClass = codeModel._class("Team");
        JDefinedClass coachClass = codeModel._class("Coach");
        teamClass.field(JMod.PRIVATE, coachClass, "coach");

        JClass arrayListClass = codeModel.ref(ArrayList.class);
        JClass arrayListOfCoachClass = arrayListClass.narrow(coachClass);
        teamClass.field(JMod.PRIVATE, arrayListOfCoachClass, "coaches");

        codeModel.build(new File("."));
    }

}

It generates the (empty) class Coach, and the class Team as

import java.util.ArrayList;

public class Team {

    private Coach coach;
    private ArrayList<Coach> coaches;

}

(I hope this answer is sufficient. And although the links might die in the future: I found these tutorials very helpful to get a first grip on the CodeModel _{Edit: Links updated, see below} : CodeModel Basics, CodeModel Inheritance)

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EDIT: Indeed, the links died. They should only be considered as "supplemental", or as a pointer for further reading. The main information (regarding the original question) should be contained in this answer. I don't have a recommendation for other tutorials (except for what everybody may find with basic websearches), but for now, I replaced the links with their latest snapshots from the web archive.