service.java

import pl.jrj.db.IDbManager;

import javax.ejb.EJBException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * @author Michał Winnicki
 * @version 1.0
 */
@Path(value = "/")
public class CService {

    private static String name;
    private static final SimpleDateFormat FORMAT =
            new SimpleDateFormat("yyyyMMdd");
    private EntityManager entityManager;

    /**
     *
     * @return number of valid insurances today
     */
    @Path(value = "/valid")
    @GET
    @Produces(value = MediaType.TEXT_PLAIN)
    public Long getTodayValidInsurances() {
        if (registerSuccessful()) {
            return getAllValidInsurancesAtDate(today());
        } else {
            return -1L;
        }
    }

    /**
     *
     * @param param - path param defining either date or number of days
     * @return number of valid insurances at given date or
     * number of valid insurances n days after today
     */
    @Path(value = "/valid/{param}")
    @GET
    @Produces(value = MediaType.TEXT_PLAIN)
    public Long getInsurancesAfterDateOrNDays(@PathParam("param")
                                                      String param) {
        if (registerSuccessful()) {
            try {
                Date date = FORMAT.parse(param);
                return getAllValidInsurancesAtDate(date);
            } catch (ParseException e) {
                return getValidInsurancesNDaysAfterDate(param);
            }
        } else {
            return -1L;
        }
    }

    /**
     *
     * @param dateParam - path param representing date
     * @param daysParam - path param representing number of days
     * @return - number of valid insurances n days after given date
     */
    @Path(value = "/valid/{dateParam}/{daysParam}")
    @GET
    @Produces(value = MediaType.TEXT_PLAIN)
    public Long getValidInsurancesNDaysAfterDate(@PathParam("dateParam")
                                                         String dateParam,
                                                 @PathParam("daysParam")
                                                         String daysParam) {
        if (registerSuccessful()) {
            try {
                Date date = FORMAT.parse(dateParam);
                return getValidInsurancesNDaysAfterDate(daysParam, date);
            } catch (ParseException e) {
                return getAllValidInsurancesAtDate(today());
            }
        } else {
            return -1L;
        }
    }

    private Long getValidInsurancesNDaysAfterDate(String param) {
        try {
            return getValidInsurancesNDaysAfterDate(param,
                    today());
        } catch (NumberFormatException e2) {
            return getAllValidInsurancesAtDate(today());
        }
    }

    private boolean registerSuccessful() {
        try {
            name = "java:global/ejb-project/DbManager!pl.jrj.db.IDbManager";
            IDbManager d = (IDbManager) new InitialContext().lookup(name);
            return d.register(7, "108225");
        } catch (EJBException | NamingException e) {
            return false;
        }
    }

    private Long getValidInsurancesNDaysAfterDate(String days, Date date) {
        Integer daysAfterDate = Integer.valueOf(days);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DATE, daysAfterDate);
        return getAllValidInsurancesAtDate(calendar.getTime());
    }

    private Long getAllValidInsurancesAtDate(final Date date) {
        return getEntityManager().createQuery(
                "SELECT count(i) from TbInsurance i " +
                        "where i.dateFrom <= :date AND " +
                        "i.dateTo >= :date", Long.class)
                                 .setParameter("date", date)
                                 .getSingleResult();
    }

    private EntityManager getEntityManager() {
        if (entityManager == null) {
            entityManager = Persistence
                    .createEntityManagerFactory("persistence108225")
                    .createEntityManager();
        }
        return entityManager;
    }

    private Date today() {
        return new Date();
    }
}