org.jug.bg.bdd.web.health.BMICalculatorServlet.java Source code

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Here is the source code for org.jug.bg.bdd.web.health.BMICalculatorServlet.java

Source

package org.jug.bg.bdd.web.health;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;
import org.jug.bg.bdd.domain.health.BMICalculator;
import org.jug.bg.bdd.domain.health.BodyMassIndex;
import org.jug.bg.bdd.domain.health.HealthRecord;
import org.jug.bg.bdd.domain.health.WeightClassifier;
import org.jug.bg.bdd.domain.health.impl.ISUHealthRecord;
import org.jug.bg.bdd.domain.health.impl.MetricBMICalculator;
import org.jug.bg.bdd.domain.health.impl.WeightClassifierImpl;

/**
 * Simple servlet which handles the web based version of the BMI calculator.
 * 
 * <p>
 * 2011, Bulgarian Java Users Group<br/>
 * Some rights reserved. This work is licensed under a <a rel="license"
 * http://creativecommons.org/licenses/by/3.0/">CC BY 3.0</a>.
 * </p>
 * 
 * @author Nikolay Vasilev
 */
public class BMICalculatorServlet extends HttpServlet {

    // --- Constants -----------------------------------------------------------

    // bloody eclipse
    private static final long serialVersionUID = 4923255477887606626L;

    // --- Instance Variables --------------------------------------------------

    private BMICalculator bmiCalculator;
    private WeightClassifier weightClasifier;

    // --- Constructors --------------------------------------------------------

    public BMICalculatorServlet() {
        bmiCalculator = new MetricBMICalculator();
        weightClasifier = new WeightClassifierImpl();
    }

    // --- Methods (HttpServlet) -----------------------------------------------

    @Override
    public void doGet(HttpServletRequest aRequest, HttpServletResponse aResponse)
            throws ServletException, IOException {
        doPost(aRequest, aResponse);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String massStr = request.getParameter(WebConstants.PARAM_MASS);
        String heightStr = request.getParameter(WebConstants.PARAM_HEIGHT);
        HealthRecord healthRecord = null;
        BodyMassIndex bmi = null;
        if (StringUtils.isEmpty(massStr) || StringUtils.isEmpty(heightStr)) {
            sendErrorRedirect(request, response, WebConstants.PAGE_BMI_CALC, null);
            return;
        }
        try {
            healthRecord = createHealthRecord(massStr, heightStr);
            bmi = bmiCalculator.calculate(healthRecord);
        } catch (Exception e) {
            sendErrorRedirect(request, response, WebConstants.PAGE_BMI_CALC, e);
            return;
        }

        request.setAttribute(WebConstants.PARAM_HEALTH_RECORD, healthRecord);
        request.setAttribute(WebConstants.PARAM_BMI, bmi);
        request.setAttribute(WebConstants.PARAM_WEIGHT_CATEGORY, weightClasifier.assess(bmi));

        getServletConfig().getServletContext().getRequestDispatcher(WebConstants.PAGE_BMI_RESULT).forward(request,
                response);
    }

    // --- Methods (Auxiliary) -------------------------------------------------

    private HealthRecord createHealthRecord(String massStr, String heightStr) {
        float mass = Float.parseFloat(massStr);
        float height = Float.parseFloat(heightStr);
        ISUHealthRecord healthRecord = new ISUHealthRecord();
        healthRecord.setWeight(mass);
        healthRecord.setHeight(height);
        return healthRecord;
    }

    private void sendErrorRedirect(HttpServletRequest request, HttpServletResponse response, String errorPageURL,
            Throwable e) throws ServletException, IOException {
        request.setAttribute(WebConstants.PARAM_HAS_PROBLEM, Boolean.TRUE.toString());
        request.setAttribute(WebConstants.PARAM_PROBLEM, e);
        getServletConfig().getServletContext().getRequestDispatcher(errorPageURL).forward(request, response);
    }
}