Authentication Intercepter

AuthInterceptor.java

package com.taxiqq.driver.network;

import android.content.Context;
import android.content.SharedPreferences;

import java.io.IOException;

import okhttp3.Credentials;
import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;

public class AuthInterceptor implements Interceptor {

    private String credentials;
    private static AuthInterceptor instance;

    private AuthInterceptor() {}

    public static AuthInterceptor getInstance() {
        if (instance == null) instance = new AuthInterceptor();
        return instance;
    }

    public void setCredentials(Context context, String user, String password) {
        this.credentials = Credentials.basic(user, password);
        save(context);
    }

    public void logout(Context context) {
        SharedPreferences preferences = context.getSharedPreferences("myPreferences",Context.MODE_PRIVATE);
        preferences.edit().putString("authCredentials",null).apply();
    }

    private void save(Context context) {
        SharedPreferences preferences = context.getSharedPreferences("myPreferences",Context.MODE_PRIVATE);
        preferences.edit().putString("authCredentials",credentials).apply();
    }

    public Boolean retrieveAuth(Context context) {
        SharedPreferences preferences = context.getSharedPreferences("myPreferences", Context.MODE_PRIVATE);
        String credentials = preferences.getString("authCredentials", null);

        if (credentials != null && credentials.length() > 4) {
            this.credentials = credentials;
            return true;
        }
        return false;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Request authenticatedRequest = request.newBuilder()
                .header("Authorization", credentials).build();
        return chain.proceed(authenticatedRequest);
    }

    public String getCredentials() {
        return credentials;
    }
}

BaseAPI.java

package ai.saal.saalmilitary.base

import com.taxiqq.driver.BuildConfig
import com.taxiqq.driver.network.AuthInterceptor
import com.taxiqq.driver.network.APIService
import okhttp3.OkHttpClient
import okhttp3.logging.HttpLoggingInterceptor
import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import java.util.concurrent.TimeUnit

open class BaseAPI {

    private val timeout = BuildConfig.Timeout.toLong()
    private var retrofit : Retrofit

    init {
        val okHttpClient = OkHttpClient.Builder()
                .addInterceptor(AuthInterceptor.getInstance())//.addInterceptor(ThreatAnalysisMockClient( MyApplication.instance.applicationContext as Context))
                .addInterceptor(HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BODY))
                .readTimeout(timeout, TimeUnit.SECONDS)
                .connectTimeout(timeout, TimeUnit.SECONDS)
                .build()
        retrofit =  Retrofit.Builder()
                .baseUrl(getBaseURL())
                .addConverterFactory(GsonConverterFactory.create())
                .client(okHttpClient)
                .build()
    }

    open fun getBaseURL() : String {return ""}
    open fun getRetrofit() : APIService {
        return retrofit.create(APIService::class.java)
    }
}