Realm Cascade

ApiService.java

package com.shakdwipeea.realmcascade;

import com.shakdwipeea.realmcascade.model.ModelA;

import retrofit2.Call;
import retrofit2.http.GET;

/**
 * Created by ashak on 18-09-2016.
 */
public interface ApiService {
    @GET("/")
    Call<ModelA> getData();
}

BaseRealmObject.java

package com.shakdwipeea.realmcascade;

/**
 * Created by ashak on 18-09-2016.
 */
public interface BaseRealmObject {
    void delete();
}

data.js

router.get('/', function(req, res, next) {
	res.json({
		message: "Modela message",
		modelBs: [
			{
				message: "Model B message",
				modelCs: [
					{ message: "Model C message" },
					{ message: "Model C message 2"}
				]
			},
			{
				message: "Model B message 2",
				modelCs: [
					{ message: "Model C message 2.1" },
					{ message: "Model C message 2.2"}
				]
			}
		]
	})
});

MainActivity.java

package com.shakdwipeea.realmcascade;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.shakdwipeea.realmcascade.model.ModelA;
import com.shakdwipeea.realmcascade.model.ModelB;
import com.shakdwipeea.realmcascade.model.ModelC;

import io.realm.Realm;
import io.realm.RealmConfiguration;
import io.realm.RealmResults;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class MainActivity extends AppCompatActivity implements Callback<ModelA>, View.OnClickListener {

    private TextView dataBefore;
    private Realm realm;
    private Button deleteButton;
    private Button clearDB;
    private Button getData;

    ApiService service;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        dataBefore = (TextView) findViewById(R.id.data_before);
        deleteButton = (Button) findViewById(R.id.delete);
        clearDB = (Button) findViewById(R.id.delete_all);
        getData = (Button) findViewById(R.id.get_data);


        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://192.168.0.110:3000")
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        RealmConfiguration realmConfig = new RealmConfiguration.Builder(this)
                .deleteRealmIfMigrationNeeded()
                .build();
        Realm.setDefaultConfiguration(realmConfig);

        realm = Realm.getDefaultInstance();

        service = retrofit.create(ApiService.class);
        getData();

        deleteButton.setOnClickListener(this);
        clearDB.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clearRealm();
            }
        });
        getData.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getData();
            }
        });
    }

    public void getData() {
        service.getData().enqueue(this);
    }

    @Override
    public void onResponse(Call<ModelA> call, final Response<ModelA> response) {
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.copyToRealm(response.body());
            }
        });

        printDb();
    }

    public void printDb() {
        ModelA first = realm.where(ModelA.class)
                .findFirst();

        System.out.println("model a " + (first != null ? first.getMessage() : "Empty"));

        RealmResults<ModelB> modelBs = realm.where(ModelB.class)
                .findAll();

        for (ModelB m: modelBs) {
            System.out.println("Model B 0" + m.getMessage());
        }

        RealmResults<ModelC> all = realm.where(ModelC.class).findAll();

        for (ModelC c : all) {
            System.out.println("Modelc " + c.getMessage());
        }

        if (first != null)
            dataBefore.setText(first.getMessage() + first.getModelBs().toString());
    }

    @Override
    public void onFailure(Call<ModelA> call, Throwable t) {
        dataBefore.setText(t.getMessage());
        t.printStackTrace();
    }

    @Override
    public void onClick(View v) {
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                ModelA modelA = realm.where(ModelA.class)
                        .findFirst();

                if (modelA != null)
                    modelA.delete();
                else
                    dataBefore.setText("No mdoela A[resent");
            }
        });

        printDb();
    }

    public void clearRealm() {
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.where(ModelA.class).findAll().deleteAllFromRealm();
                realm.where(ModelB.class).findAll().deleteAllFromRealm();
                realm.where(ModelC.class).findAll().deleteAllFromRealm();
            }
        });

        printDb();
    }
}

model_ModelA.java

package com.shakdwipeea.realmcascade.model;

import com.google.gson.Gson;
import com.shakdwipeea.realmcascade.BaseRealmObject;

import java.util.List;

import io.realm.RealmList;
import io.realm.RealmObject;

/**
 * Created by ashak on 18-09-2016.
 */
public class ModelA extends RealmObject implements BaseRealmObject {
    private String message;
    private RealmList<ModelB> modelBs;

    public ModelA() {
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public List<ModelB> getModelBs() {
        return modelBs;
    }

    public void setModelBs(RealmList<ModelB> modelBs) {
        this.modelBs = modelBs;
    }

    @Override
    public String toString() {
        return new Gson().toJson(this);
    }

    @Override
    public void delete() {
        RealmUtil.deleteManagedList(modelBs);
        deleteFromRealm();
    }
}

model_ModelB.java

package com.shakdwipeea.realmcascade.model;

import com.google.gson.Gson;
import com.shakdwipeea.realmcascade.BaseRealmObject;

import java.util.List;

import io.realm.RealmList;
import io.realm.RealmObject;

/**
 * Created by ashak on 18-09-2016.
 */
public class ModelB extends RealmObject implements BaseRealmObject {
    private String message;
    private RealmList<ModelC> modelCs;

    public ModelB() {
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public List<ModelC> getModelCs() {
        return modelCs;
    }

    public void setModelCs(RealmList<ModelC> modelCs) {
        this.modelCs = modelCs;
    }

    @Override
    public String toString() {
        return new Gson().toJson(this);
    }

    @Override
    public void delete() {
        modelCs.deleteAllFromRealm();
        deleteFromRealm();
    }
}

model_ModelC.java

package com.shakdwipeea.realmcascade.model;

import com.google.gson.Gson;
import com.shakdwipeea.realmcascade.BaseRealmObject;

import io.realm.RealmObject;

/**
 * Created by ashak on 18-09-2016.
 */
public class ModelC extends RealmObject implements BaseRealmObject {
    private String message;

    public ModelC(String message) {
        this.message = message;
    }

    public ModelC() {
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return new Gson().toJson(this);
    }

    @Override
    public void delete() {
        this.deleteFromRealm();
    }
}

RealmUtil.java

package com.shakdwipeea.realmcascade;

import io.realm.RealmList;

/**
 * Created by ashak on 19-09-2016.
 */
public class RealmUtil {
    public static void deleteNestedList(RealmList<? extends BaseRealmObject> list) {
        int length = list.size();
        for (int i = 0; i < length; i++) {
            // since we are dealing with live objects
            list.get(0).delete();
        }
    }
}