Welcome to G3CodeGenerator

The source repository for the code generator project developed as part of video this youtube video series.

It contains the Annotations and Processor for generating the data-layer code which persist the data in a local file.

How to use this library?

Locally checkout this git repository on your machine and run the following commands from the root folder of the repository.

mvn package

mvn install

Once you run the above commands, a jar file will be generated and put in your local maven repository.

Now, create a new maven project where you would like to use this library and add the following dependency in your pom file.

<dependency>
      <groupId>com.gogettergeeks</groupId>
      <artifactId>G3CodeGenerator</artifactId>
      <version>1.0.0</version>
      <scope>provided</scope>
    </dependency>

And thats it! In your project, you can start using the annotations and all you need to do is build your project to generate the data-layer and start using it!

Available Annotations

1. FileDBGenerated: Use this annotation at any model class for which you want to generate the data-layer. 2. Persisted: Use this annotations on the fields (within your model class) you want to persist in file based DB. 3. UniqueKey: Use this annotation on primary key or unique key field which identifies the record uniquely.

Example Usage

Consider the below Student model class.

import com.gogettergeeks.annotation.FileDBGenerated;
import com.gogettergeeks.annotation.Persisted;
import com.gogettergeeks.annotation.UniqueKey;

@FileDBGenerated
public class Student {
    @Persisted
    private String name;

    @Persisted
    @UniqueKey
    private int rollNumber;

    private double percentage;

    public String getName() {
        return name;
    }

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

    public int getRollNumber() {
        return rollNumber;
    }

    public void setRollNumber(int rollNumber) {
        this.rollNumber = rollNumber;
    }
}

Here, we have three fields: (1) Name, (2) RollNumber, and (3) Percentage. Percentage field is not annotated with @Persisted or @UniqueKey and hence this field won't be persisted in file.

Now simply build the project and you'll see 5 files getting generated.

1. StudentDao
2. StudentDaoImpl
3. StudentDtoGenerated
4. StudentRequestException
5. StudentServiceException

You can now use the generated files, a sample usage can be found below

public class Main 
{
    public static void main( String[] args ) throws Exception
    {
        System.out.println("====================== START ===========================");
        StudentDao dao = new StudentDaoImpl();
        List<Student> students = dao.getAll();
        for (Student s : students) {
            System.out.println("Name: " + s.getName() + " | RollNumber: " + s.getRollNumber());
        }
        
        System.out.println("==================== ADD =======================");
        Student s1 = new Student();
        s1.setName("John");
        s1.setRollNumber(1);

        Student s2 = new Student();
        s2.setName("Tom");
        s2.setRollNumber(2);

        Student s3 = new Student();
        s3.setName("Pop");
        s3.setRollNumber(3);

        Student s4 = new Student();
        s4.setName("Baburao");
        s4.setRollNumber(4);

        dao.add(s1);
        dao.add(s2);
        dao.add(s3);
        dao.add(s4);

        students = dao.getAll();

        for (Student s : students) {
            System.out.println("Name: " + s.getName() + " | RollNumber: " + s.getRollNumber());
        }
        
        System.out.println("=================== UPDATE =============================");
        s1.setName("Sam");
        dao.update(s1);

        students = dao.getAll();
        for (Student s : students) {
            System.out.println("Name: " + s.getName() + " | RollNumber: " + s.getRollNumber());
        }
        
        System.out.println("==================== DELETE ==========================");
        dao.delete(s1);

        students = dao.getAll();
        for (Student s : students) {
            System.out.println("Name: " + s.getName() + " | RollNumber: " + s.getRollNumber());
        }
        System.out.println("==================== END ==========================");
    }
}