covid_10012023_covid-reports/src/Main.java

import data.dtos.QueryDTO;
import data.enums.CustomPreparedStatementsRead;
import data.repos.QueryResultsRepository;
import services.AppConfigService;
import services.DatabaseService;
import services.ReportGenerationService;

import java.sql.SQLException;

/**
 * Entry point of the application
 */
public class Main {
    public static void main(String[] args) {
        final App app = new App();
        app.run();
    }
}

/**
 * Responsible for the overall flow of the application. It creates and manages instances Services.
 */
class App {
    public App() {
        databaseService = new DatabaseService();
        appConfigService = new AppConfigService();
        reportGenerationService = new ReportGenerationService();
    }

    final private DatabaseService databaseService;
    final private AppConfigService appConfigService;
    final private ReportGenerationService reportGenerationService;

    /**
     * Endpoints mentioned under the `Report` section
     */
    private static final CustomPreparedStatementsRead[] reportEndpoints = {
            CustomPreparedStatementsRead.HighestAndLowest10Vaccination,
            CustomPreparedStatementsRead.HighestInfectionsPer100K,
            CustomPreparedStatementsRead.CountriesLaggingBehind,
    };

    /**
     * Endpoints mentioned under the `Query` section
     */
    private static final CustomPreparedStatementsRead[] queryEndpoints = {
            CustomPreparedStatementsRead.DailyInfectionsAndDeathAggregate,
    };

    /**
     * Responsible for the overall flow of the application.
     * It retrieves data from the database using the `DatabaseService` class,
     * generates reports using the `ReportGenerationService` class, and prompts the user for input using the `AppConfigService` class.
     */
    public void run() {
        executeNoInteractionEndpointPipeline(reportEndpoints);
        executeInteractiveEndpointPipeline(queryEndpoints);
    }

    /**
     * This method is responsible for executing a pipeline of read-only queries, using a provided set of
     * {@link CustomPreparedStatementsRead} queryEndpoints, without any user interaction.
     * The method will iterate over the provided queryEndpoints, and for each query it will:
     * Execute the read query using {@link DatabaseService#getReadReportsEndpoint(QueryDTO)}
     * Store the results in a new {@link QueryResultsRepository}
     * Generate a report for the stored results using {@link ReportGenerationService#reportBaseResults(QueryResultsRepository)}
     * @param queryEndpoints an array of {@link CustomPreparedStatementsRead} containing the queries to be executed.
     * @throws RuntimeException when there is a SQLException thrown by {@link DatabaseService#getReadReportsEndpoint(QueryDTO)}
     */
    private void executeNoInteractionEndpointPipeline(CustomPreparedStatementsRead[] queryEndpoints) {
        QueryResultsRepository resultsRepository;
        for (final CustomPreparedStatementsRead query : queryEndpoints) {
            try {
                resultsRepository = databaseService.getReadReportsEndpoint(new QueryDTO(query));
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
            reportGenerationService.reportBaseResults(resultsRepository);
        }
    }

    /**
     * Executes a series of read queries specified in the {@code queryEndpoints} parameter, and prompts the user for input of country name and date.
     * The results of the queries are passed to reportGenerationService to be reported.
     * @param queryEndpoints the endpoints to execute in the pipeline
     * @throws RuntimeException if a SQLException occurs when getting the read reports endpoint
     */
    private void executeInteractiveEndpointPipeline(CustomPreparedStatementsRead[] queryEndpoints) {
        QueryResultsRepository resultsRepository;
        try {
            for(final CustomPreparedStatementsRead query: queryEndpoints) {
                appConfigService.promptAndSetUserArguments();
                resultsRepository = databaseService.getReadReportsEndpoint(new QueryDTO(query, new Object[]{appConfigService.getCountryName(), appConfigService.getDate(),}));
                reportGenerationService.reportBaseResults(resultsRepository);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}