]> git.mxchange.org Git - pizzaservice-war.git/blobdiff - src/java/org/mxchange/pizzaapplication/application/PizzaServiceApplication.java
Removed more deprecated and no longer used methods + kept one for functionality
[pizzaservice-war.git] / src / java / org / mxchange / pizzaapplication / application / PizzaServiceApplication.java
index 647ab17969d945a8a9ad13845011632fb8d9a81e..a542e56aab003a95cdef6b35805a0060c235465a 100644 (file)
  */
 package org.mxchange.pizzaapplication.application;
 
-import java.lang.reflect.Field;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.lang.reflect.InvocationTargetException;
+import java.sql.SQLException;
 import java.text.MessageFormat;
 import java.util.Iterator;
-import java.util.Map;
-import java.util.SortedMap;
-import java.util.TreeMap;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
-import org.mxchange.jcore.contact.Gender;
+import org.mxchange.jcore.exceptions.BadTokenException;
+import org.mxchange.jcore.exceptions.CorruptedDatabaseFileException;
+import org.mxchange.jcore.exceptions.UnsupportedDatabaseBackendException;
+import org.mxchange.jshop.category.Category;
+import org.mxchange.jshop.database.frontend.category.CategoryDatabaseFrontend;
+import org.mxchange.jshop.database.frontend.category.CategoryFrontend;
+import org.mxchange.jshop.database.frontend.product.ProductDatabaseFrontend;
+import org.mxchange.jshop.database.frontend.product.ProductFrontend;
+import org.mxchange.jshop.exceptions.CategoryTitleAlreadyUsedException;
+import org.mxchange.jshop.exceptions.ProductTitleAlreadyUsedException;
+import org.mxchange.jshop.item.AddableBasketItem;
+import org.mxchange.jshop.product.Product;
 import org.mxchange.pizzaapplication.BasePizzaServiceSystem;
-import org.mxchange.pizzaapplication.customer.Customer;
-import org.mxchange.pizzaapplication.customer.PizzaServiceCustomer;
-import org.mxchange.pizzaapplication.product.PizzaProduct;
-import org.mxchange.pizzaapplication.product.Product;
 
 /**
+ * Main application class
  *
  * @author Roland Haeder
  */
 public class PizzaServiceApplication extends BasePizzaServiceSystem implements PizzaApplication {
        /**
-        * Main title
+        * Frontend for products
         */
-       public static final String MAIN_TITLE = "Pizza-Service";
+       private ProductFrontend productFrontend;
 
        /**
-        * Product list
+        * Frontend for categories
         */
-       private final SortedMap<String, Product> products;
+       private CategoryFrontend categoryFrontend;
 
        /**
-        * Some singleton getter for this instance. If the instance is not set in
-        * given application, it will be created.
-        *
-        * @param application Servlet context
-        * @return This instance
-        * @throws javax.servlet.ServletException If object is not set correctly
+        * Default constructor
         */
-       public static final PizzaApplication getInstance (final ServletContext application) throws ServletException {
-               // Check application instance
-               if (application == null) {
-                       // Not set
-                       throw new NullPointerException("application is null"); //NOI18N
-               }
-
-                       // Init instance
-               PizzaApplication instance = null;
-
-               // Get instance from servlet application (aka. "application scope")
-               Object object = application.getAttribute("app"); //NOI18N
-
-               // Is it set?
-               if (object instanceof PizzaApplication) {
-                       // Instance is set, so casting should work
-                       instance = (PizzaApplication) object;
-               } else if (object instanceof Object) {
-                       // Not correct instance
-                       throw new ServletException("app is not set correctly"); //NOI18N
-               } else {
-                       // "service" is null, so initialize it
-                       instance = new PizzaServiceApplication();
-
-                       // And set it here
-                       application.setAttribute("app", instance); //NOI18N
-               }
-
+       public PizzaServiceApplication () {
                // Trace message
-               instance.getLogger().trace(MessageFormat.format("instance={0} - EXIT!", instance)); //NOI18N
-
-               // Return it
-               return instance;
-       }
-
-       /**
-        * Private constructor
-        */
-       private PizzaServiceApplication () {
-               // Init products instance
-               this.products = new TreeMap<>();
-
-               // Init bundle
-               this.initBundle();
-
-               // Fill products list
-               this.fillProductsList();
-       }
-
-       @Override
-       public void doBootstrap () {
-               throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
-       }
-
-       @Override
-       public void doMainLoop () {
-               throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
+               this.getLogger().trace("CALLED!");
        }
 
        @Override
-       public void doShutdown () {
-               throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
-       }
-
-       /**
-        * Adds given product to list or throws an exception if name is already found
-        *
-        * @param name Internal name of product
-        * @param title Product's title
-        * @param price Price
-        */
-       private void addProduct (final String name, final String title, final float price) {
+       public void init (final ServletContext context) throws UnsupportedDatabaseBackendException, SQLException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("name={0},title={1},price={2} - CALLED!", name, title, price)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("context={0} - CALLED!", context)); //NOI18N
 
-               // Is the name already used?
-               if (this.isProductNameUsed(name)) {
-                       // Something went wrong
-                       throw new IllegalArgumentException(MessageFormat.format("product {0} is already used.", name)); //NOI18N
+               // context should not be null
+               if (null == context) {
+                       // Abort here
+                       throw new NullPointerException("context is null");
                }
 
-               // Instance product
-               Product product = new PizzaProduct(name, title, price);
-
-               // Debug message
-               this.getLogger().debug(MessageFormat.format("Adding product={0} ...", product)); //NOI18N
-
-               // Add it
-               this.products.put(product.getName(), product);
-
-               // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
-       }
-
-       /**
-        * Clears given parameter for product in session
-        * 
-        * @param product Product instance
-        * @param session Session instance
-        * @param parameter Parameter to clear
-        */
-       private void clearSessionAttribute (final Product product, final HttpSession session, final String parameter) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("produce={0},parameter={1},session={2} - CALLED!", product, parameter, session)); //NOI18N
-
-               // Clear in session
-               this.getLogger().debug(MessageFormat.format("Clearing product={0},parameter={1} ...", product.getName(), parameter)); //NOI18N
-               this.setValueInSession(product, session, parameter, null);
-
-               // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
-       }
+               // Is the bundle initialized?
+               if (!this.isBundledInitialized()) {
+                       // Temporary initialize default bundle
+                       // @TODO The enum Gender uses this
+                       this.initBundle();
+               }
 
-       /**
-        * Fills products list
-        * @todo Very hard-coded stuff ...
-        */
-       private void fillProductsList () {
-               // Trace message
-               this.getLogger().trace("CALLED!"); //NOI18N
+               // Initialize properties from context
+               this.initProperties(context);
 
-               // Add products
-               this.addProduct("italia", "Pizza Italia", 5.50f); //NOI18N
-               this.addProduct("diablo", "Pizza Diablo", 7.80f); //NOI18N
-               this.addProduct("bolognese", "Spagetti Bolognese", 11.95f); //NOI18N
+               // Init database frontends
+               this.initDatabaseFrontends();
 
                // Trace message
                this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Some getter for value from session
-        *
-        * @param product Product instance
-        * @param session Session instance
-        * @param attribute Attribute to get value from
-        * @return Value from session
-        */
-       private Object getValueFromSession (final Product product, final HttpSession session, final String attribute) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1},attribute={2} - CALLED!", product, session, attribute)); //NOI18N
-
-               // Init variable
-               Object value = this.getValueFromSession(session, String.format(HTTP_PARAM_MASK, product.getName(), attribute));
-
-               this.getLogger().debug(MessageFormat.format("product={0},attribute={1},value={2}", product.getName(), attribute, value)); //NOI18N
-
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("value={0} - EXIT!", value)); //NOI18N
-
-               // Return it
-               return value;
-       }
-
-       /**
-        * Some getter for value from session
+        * Calculates total amount of all choosen products
         *
+        * @param request Request instance
         * @param session Session instance
-        * @param key Key to get value from
-        * @return Value from session
+        * @return Total amount of all choosen products
+        * @deprecated Old lost 
         */
-       private Object getValueFromSession (final HttpSession session, final String key) {
+       @Deprecated
+       private int calculateTotalAmount (final HttpServletRequest request, final HttpSession session) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("session={043},key={1} - CALLED!", session, key)); //NOI18N
-
-               // Init value
-               Object value = null;
+               this.getLogger().trace(MessageFormat.format("request={0},session={1} - CALLED!", request, session)); //NOI18N
 
-               // Get it synchronized from session
-               synchronized (session) {
-                       value = session.getAttribute(key);
+               // Is product and session set?
+               if (null == request) {
+                       // Not set
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == session) {
+                       // Not set
+                       throw new NullPointerException("session is null"); //NOI18N
                }
 
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("value={0} - EXIT!", value)); //NOI18N
+               // Init/declare total price and iterator
+               int totalAmount = 0;
+               Iterator<Product> iterator = this.getAvailableProducts();
 
-               // Return it
-               return value;
-       }
+               // "Walk" over all products
+               while (iterator.hasNext()) {
+                       // Get next product
+                       Product product = iterator.next();
 
-       /**
-        * Checks whether given product is already used
-        *
-        * @param name Name of product
-        * @return Whether the given product's name is already used
-        */
-       private boolean isProductNameUsed (final String name) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("name={0} - CALLED!", name)); //NOI18N
+                       // Is this choosen?
+                       if (this.isProductChoosen(product, request, session)) {
+                               // Then add ordered amount
+                               this.getLogger().debug(MessageFormat.format("Counting {0} ...", product.getItemId())); //NOI18N
 
-               // Is it found?
-               return this.products.containsKey(name);
-       }
+                               // Getting amount
+                               String amount = this.getAmountFromSession(product, session);
 
-       /**
-        * For debugging purpose
-        *
-        * @param args Arguments
-        */
-       public static void main (String[] args) {
-               // Get instance and start it
-               new PizzaServiceApplication().start();
-       }
+                               // Add it up
+                               this.getLogger().debug(MessageFormat.format("amount={0}", amount)); //NOI18N
+                               totalAmount += Integer.valueOf(amount);
+                       }
+                       this.getLogger().debug(MessageFormat.format("product={0},totalAmount={1}", product.getItemId(), totalAmount)); //NOI18N
+               }
 
-       /**
-        * Checks if the product ordered?
-        *
-        * @param product 
-        * @param session
-        * @return 
-        */
-       private boolean isProductOrdered (final Product product, final HttpSession session) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
-
-               // Get session
-               Object isOrdered = this.getValueFromSession(product, session, SESSION_ORDERED);
-               this.getLogger().debug(MessageFormat.format("product={0},isOrdered={1}", product.getName(), isOrdered)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("totalAmount={0} - EXIT!", totalAmount)); //NOI18N
 
-               // Return result
-               return ("true".equals(isOrdered)); //NOI18N
+               // Return total price
+               return totalAmount;
        }
 
-       /**
-        * Somewhat setter in session
-        *
-        * @param product Product instance
-        * @param session Session instance
-        * @param keyPart Key part to include in final key
-        * @param value Value to set
-        */
-       private void setValueInSession (final Product product, final HttpSession session, final String keyPart, final Object value) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1},keyPart={2},value={3} - CALLED!", product, session, keyPart, value)); //NOI18N
-
-               synchronized(session) {
-                       // Set it synced
-                       this.getLogger().debug(MessageFormat.format("Setting value={0} for product={1},keyPart={2}", value, product.getName(), keyPart)); //NOI18N
-                       this.setValueInSession(session, String.format(HTTP_PARAM_MASK, product.getName(), keyPart), value);
-               }
-
-               // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
+       @Override
+       public void doBootstrap () {
+               throw new UnsupportedOperationException("Not supported yet."); //NOI18N
        }
 
-       /**
-        * Somewhat setter in session
-        *
-        * @param session Session instance
-        * @param key Session key to set
-        * @param value Value to set
-        */
        @Override
-       public void setValueInSession (final HttpSession session, final String key, final Object value) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("session={0},key={1},value={2} - CALLED!", session, key, value)); //NOI18N
-
-               synchronized(session) {
-                       // Set it synced
-                       session.setAttribute(key, value);
-               }
-
-               // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
+       public void doMainLoop () {
+               throw new UnsupportedOperationException("Not supported yet."); //NOI18N
        }
 
-       /**
-        * Application starter
-        */
-       private void start () {
-               // "Walk" over all products
-               for (final Product product : this.getProducts()) {
-                       // Output data
-                       this.getLogger().debug(MessageFormat.format("Product {0}, {1}: {2}", product.getName(), product.getTitle(), product.getPrice())); //NOI18N
-               }
-
-               // Generate fake Customer instance
-               Customer customer = new PizzaServiceCustomer();
-
-               /*
-                * Need a least a gender ... :( See, that is why I don't like default
-                * constructors, you can easily miss something important and bam! You
-                * get an NPE. The fix here is, to have construtors (or factories) which
-                * requires all required instances that needs to be set to get a
-                * consitent object back.
-                */
-
-               // Gender is MALE now
-               customer.setGender(Gender.MALE);
-
-               // Get iterator on all its fields
-               Iterator<Map.Entry<Field, Object>> it = customer.iterator();
-
-               // Output it
-               while (it.hasNext()) {
-                       Map.Entry<Field, Object> entry = it.next();
-                       this.getLogger().debug(MessageFormat.format("entry {0}={1}", entry.getKey(), entry.getValue()));
-               }
+       @Override
+       public void doShutdown () {
+               throw new UnsupportedOperationException("Not supported yet."); //NOI18N
        }
 
        /**
@@ -362,17 +167,18 @@ public class PizzaServiceApplication extends BasePizzaServiceSystem implements P
         * @param product Product instance
         * @param session Session instance
         * @return Amount as string
+        * @deprecated Old lost code
         */
-       @Override
-       public String getAmountFromSession (final Product product, final HttpSession session) {
+       @Deprecated
+       private String getAmountFromSession (final Product product, final HttpSession session) {
                // Trace message
                this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
 
                // Is product and session set?
-               if (product == null) {
+               if (null == product) {
                        // Not set
                        throw new NullPointerException("product is null"); //NOI18N
-               } else if (session == null) {
+               } else if (null == session) {
                        // Not set
                        throw new NullPointerException("session is null"); //NOI18N
                }
@@ -381,7 +187,7 @@ public class PizzaServiceApplication extends BasePizzaServiceSystem implements P
                Object object = this.getValueFromSession(product, session, HTTP_PARAM_AMOUNT);
 
                // Is the object null?
-               if (object == null) {
+               if (null == object) {
                        // Trace message
                        this.getLogger().trace("Returning 0 - EXIT!"); //NOI18N
 
@@ -397,665 +203,834 @@ public class PizzaServiceApplication extends BasePizzaServiceSystem implements P
        }
 
        /**
-        * Some "getter" for choose from session
+        * Some "getter" for HTML code 'checked="checked"' if the product is choosen
         * 
         * @param product Product instance
+        * @param request Request instance
         * @param session Session instance
-        * @return Choose as string
+        * @return Whether the product is choosen
         */
        @Override
-       public String getChooseFromSession (final Product product, final HttpSession session) {
+       public String getCheckedHtmlFromProduct (final Product product, final HttpServletRequest request, final HttpSession session) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
 
-                       // Is product and session set?
-               if (product == null) {
+               // Is product and session set?
+               if (null == product) {
                        // Not set
                        throw new NullPointerException("product is null"); //NOI18N
-               } else if (session == null) {
+               } else if (null == request) {
+                       // Not set
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == session) {
                        // Not set
                        throw new NullPointerException("session is null"); //NOI18N
                }
 
-               // Get attribute
-               Object object = this.getValueFromSession(product, session, HTTP_PARAM_CHOOSE);
+               // First let's check if the product is choosen
+               if (this.isProductChoosen(product, request, session)) {
+                       // Trace message
+                       this.getLogger().trace("Returning checked=\"checked\" - EXIT!"); //NOI18N
 
-               // Is the object null?
-               if (object == null) {
-                       // Not found
-                       this.getLogger().debug(MessageFormat.format("Returning empty string for product={0} ...", product.getName())); //NOI18N
+                       // Is choosen
+                       return "checked=\"checked\""; //NOI18N
+               } else {
+                       // Trace message
+                       this.getLogger().trace("Returning empty string - EXIT!"); //NOI18N
+
+                       // Not choosen
                        return ""; //NOI18N
                }
-
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("object={0} - CALLED!", object)); //NOI18N
-
-               // Cast to string and return it
-               return (String) object;
        }
 
        /**
-        * Handler for amount from request or session
-        * 
-        * @param product Product instance
+        * Some "getter" for HTML code 'disabled="disabled"' for e.g. submit buttons
+        *
         * @param request Request instance
         * @param session Session instance
-        * @return Amount as string
+        * @return Whether the product is choosen
         */
        @Override
-       public String handleAmountFromRequestSession (final Product product, final HttpServletRequest request, final HttpSession session) {
+       public String getDisabledHtmlFromSession (final HttpServletRequest request, final HttpSession session) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("request={0},session={1} - CALLED!", request, session)); //NOI18N
 
                // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
+               if (null == request) {
                        // Not set
                        throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
+               } else if (null == session) {
                        // Not set
                        throw new NullPointerException("session is null"); //NOI18N
                }
 
-               // Init variabke
-               Object object;
-
-               // Check request method
-               if (!"POST".equals(request.getMethod())) { //NOI18N
-                       // Not POST, so get from session
-                       return this.getAmountFromSession(product, session);
-               } else if (this.handleChooseFromRequestSession(product, request, session).isEmpty()) {
-                       // Not choosen
-                       this.clearSessionAttribute(product, session, HTTP_PARAM_AMOUNT);
-                       this.getLogger().debug(MessageFormat.format("Unsetting for product={0} in session, returning zero ...", product.getName())); //NOI18N
-                       return "0"; //NOI18N
-               }
+               // Get "enabled" from request scope
+               Boolean enabled = Boolean.parseBoolean((String) request.getAttribute("enabled")); //NOI18N
 
-               // Get attribute from request
-               object = request.getParameter(String.format(HTTP_PARAM_MASK, HTTP_PARAM_AMOUNT, product.getName()));
+               // Debug message
+               this.getLogger().debug(MessageFormat.format("enabled={0}", enabled)); //NOI18N
 
-               // Is it set?
-               if (object instanceof String) {
-                       // Try to parse it to integer
-                       try {
-                               Integer value = Integer.valueOf((String) object);
-                       } catch (final NumberFormatException ex) {
-                               // Not valid input
-                               this.getLogger().warn(ex);
-                               return "0"; //NOI18N
-                       }
+               // Is something selected?
+               if ((enabled) || (this.calculateTotalAmount(request, session) > 0)) {
+                       // Trace message
+                       this.getLogger().trace("Returning empty string - EXIT!"); //NOI18N
 
-                       // Then set it in session
-                       this.setValueInSession(product, session, HTTP_PARAM_AMOUNT, object);
+                       // Something has been choosen
+                       return ""; //NOI18N
+               } else {
+                       // Trace message
+                       this.getLogger().trace("Returning disabled=\"disabled\" - EXIT!"); //NOI18N
 
-                       // And return it
-                       return (String) object;
+                       // Nothing choosen yet
+                       return "disabled=\"disabled\""; //NOI18N
                }
+       }
 
+       /**
+        * Checks if given Product instance is available and returns a printable
+        * (human-readable) string.
+        * 
+        * @param product Product instance to check
+        * @return Human-readable version of product availability
+        */
+       @Override
+       public String getPrintableProduktAvailability (final Product product) {
                // Trace message
-               this.getLogger().trace("Calling getAmountFromSession() ..."); //NOI18N
+               this.getLogger().trace(MessageFormat.format("product={0} - CALLED!", product)); //NOI18N
 
-               // Get attribute from session
-               return this.getAmountFromSession(product, session);
+               // Is it null?
+               if (null == product) {
+                       // Should not be null
+                       throw new NullPointerException("product is null"); //NOI18N
+               }
+
+               // Get availability
+               if (product.getAvailable() == true) {
+                       // Is available
+                       return "Ja";
+               } else {
+                       // Not, not for public
+                       return "Nein";
+               }
        }
 
        /**
-        * Handler for choosen (checkbox) from request or session
+        * Some "getter" for a an array of only available products
         *
-        * @param product Product instance
-        * @param request Request instance
-        * @param session Session instance
-        * @return Amount as string
+        * @return All products
         */
        @Override
-       public String handleChooseFromRequestSession (final Product product, final HttpServletRequest request, final HttpSession session) {
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
+       public Iterator<Product> getAvailableProducts () throws ServletException {
+               // categoryFrontend must be set
+               if (null == this.productFrontend) {
+                       // Abort here
+                       throw new NullPointerException("productFrontend is null");
+               }
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               try {
+                       // Ask frontend for a list of products
+                       return this.productFrontend.getAvailableProducts();
+               } catch (final IOException | BadTokenException | SQLException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
                }
+       }
 
-               // Init variabke
-               Object object;
+       /**
+        * Some "getter" for a an array of all products
+        *
+        * @return All products
+        */
+       @Override
+       public Iterator<Product> getAllProducts () throws ServletException {
+               // Trace message
+               this.getLogger().trace("CALLED!");
 
-               // Check request method
-               if (!"POST".equals(request.getMethod())) { //NOI18N
-                       // Not POST, so get from session
-                       return this.getChooseFromSession(product, session);
-               } else if (this.isProductOrdered(product, session)) {
-                       // Product is ordered
-                       return this.getChooseFromSession(product, session);
+               // categoryFrontend must be set
+               if (null == this.productFrontend) {
+                       // Abort here
+                       throw new NullPointerException("productFrontend is null");
                }
 
-               // Get reqzest element
-               object = request.getParameter(String.format(HTTP_PARAM_MASK, HTTP_PARAM_CHOOSE, product.getName()));
-               this.getLogger().debug(MessageFormat.format("product={0},object={1}", product.getName(), object)); //NOI18N
+               try {
+                       // Ask frontend for a list of products
+                       return this.productFrontend.getAllProducts();
+               } catch (final IOException | BadTokenException | SQLException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
+               }
+       }
 
-               // Is it null?
-               if (object == null) {
-                       // Unset session
-                       this.getLogger().debug(MessageFormat.format("Unsetting session for product={0} ...", product.getName())); //NOI18N
-                       this.clearSessionAttribute(product, session, HTTP_PARAM_CHOOSE);
-                       this.clearSessionAttribute(product, session, HTTP_PARAM_AMOUNT);
+       /**
+        * Some "getter" for a an array of all categories
+        *
+        * @return All categories
+        */
+       @Override
+       public Iterator<Category> getAllCategories () throws ServletException {
+               // Trace message
+               this.getLogger().trace("CALLED!");
 
-                       // Return empty string
-                       return ""; //NOI18N
+               // categoryFrontend must be set
+               if (null == this.categoryFrontend) {
+                       // Abort here
+                       throw new NullPointerException("categoryFrontend is null");
                }
 
-               // Then set it in session
-               this.setValueInSession(product, session, HTTP_PARAM_CHOOSE, object);
-
-               // Cast to string and return it
-               this.getLogger().debug(MessageFormat.format("product={0} - Returning {1} ...", product.getName(), object)); //NOI18N
-               return (String) object;
+               try {
+                       // Ask frontend for a list of categories
+                       return this.categoryFrontend.getAllCategories();
+               } catch (final IOException | BadTokenException | SQLException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
+               }
        }
 
        /**
-        * Some "getter" for choosen (checkbox) from session
+        * Checks whether the given product is choosen, request overules session.
         *
         * @param product Product instance
         * @param request Request instance
         * @param session Session instance
-        * @return Amount as string
+        * @return Whether the product is choosen
         */
        @Override
-       public String getPrintableChoosenFromRequestSession (final Product product, final HttpServletRequest request, final HttpSession session) {
+       @Deprecated
+       public boolean isProductChoosen (final Product product, final HttpServletRequest request, final HttpSession session) {
+               throw new UnsupportedOperationException("This method is deprecated and shall not be called");
+       }
+
+       /**
+        * Somewhat setter in session
+        *
+        * @param session Session instance
+        * @param key Session key to set
+        * @param value Value to set
+        */
+       @Override
+       public void setValueInSession (final HttpSession session, final String key, final Object value) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("session={0},key={1},value={2} - CALLED!", session, key, value)); //NOI18N
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               synchronized(session) {
+                       // Set it synced
+                       session.setAttribute(key, value);
                }
 
-               // Get element
-               String choosen = this.handleChooseFromRequestSession(product, request, session);
-               this.getLogger().debug(MessageFormat.format("product={0},choosen={1}", product.getName(), choosen)); //NOI18N
+               // Trace message
+               this.getLogger().trace("EXIT!"); //NOI18N
+       }
 
-               // Must not be null
-               assert(choosen instanceof String): "choosen is null"; //NOI18N
+       /**
+        * Clears given parameter for product in session
+        *
+        * @param product Product instance
+        * @param session Session instance
+        * @param parameter Parameter to clear
+        */
+       private void clearSessionAttribute (final Product product, final HttpSession session, final String parameter) {
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("produce={0},parameter={1},session={2} - CALLED!", product, parameter, session)); //NOI18N
 
-               // Is it empty?
-               if (choosen.isEmpty()) {
-                       // Not choosen
-                       return "Nein";
-               }
+               // Clear in session
+               this.getLogger().debug(MessageFormat.format("Clearing product={0},parameter={1} ...", product.getItemId(), parameter)); //NOI18N
+               this.setValueInSession(product, session, parameter, null);
+
+               // Trace message
+               this.getLogger().trace("EXIT!"); //NOI18N
+       }
 
-               // Get amount
-               String amount = this.handleAmountFromRequestSession(product, request, session);
-               this.getLogger().debug(MessageFormat.format("product={0},amount={1}", product.getName(), amount)); //NOI18N
+       /**
+        * Some getter for value from session
+        *
+        * @param product Product instance
+        * @param session Session instance
+        * @param attribute Attribute to get value from
+        * @return Value from session
+        */
+       private Object getValueFromSession (final Product product, final HttpSession session, final String attribute) {
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("product={0},session={1},attribute={2} - CALLED!", product, session, attribute)); //NOI18N
 
-               // Must not be null
-               assert(amount instanceof String): "amount is null"; //NOI18N
+               // Init variable
+               Object value = this.getValueFromSession(session, String.format(HTTP_PARAM_MASK, attribute, product.getItemId()));
+               
+               this.getLogger().debug(MessageFormat.format("product={0},attribute={1},value={2}", product.getItemId(), attribute, value)); //NOI18N
 
-               // Is it empty?
-               if (amount.isEmpty() || "0".equals(amount)) { //NOI18N
-                       // Choosen, but no amount
-                       return "Nein";
-               } else {
-                       // Is choosen
-                       return "Ja";
-               }
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("value={0} - EXIT!", value)); //NOI18N
+
+               // Return it
+               return value;
        }
 
        /**
-        * Some "getter" for total price of position from request or session.
-        * Single price and amount is multiplyed.
+        * Some getter for value from session
         *
-        * @param product Product instance
-        * @param request Request instance
         * @param session Session instance
-        * @return Amount as string
+        * @param key Key to get value from
+        * @return Value from session
         */
-       @Override
-       public float getTotalPositionPriceFromRequestSession (final Product product, final HttpServletRequest request, final HttpSession session) {
+       private Object getValueFromSession (final HttpSession session, final String key) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("session={0},key={1} - CALLED!", session, key)); //NOI18N
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // Init value
+               Object value;
+
+               // Get it synchronized from session
+               synchronized (session) {
+                       value = session.getAttribute(key);
                }
 
-               // Get choosen
-               String choosen = this.handleChooseFromRequestSession(product, request, session);
-               this.getLogger().debug(MessageFormat.format("product={0},choosen={1}", product.getName(), choosen)); //NOI18N
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("value={0} - EXIT!", value)); //NOI18N
+
+               // Return it
+               return value;
+       }
 
-               // Must not be null
-               assert(choosen instanceof String): "choosen is null"; //NOI18N
+       /**
+        * Initializes database frontends.
+        */
+       private void initDatabaseFrontends () throws UnsupportedDatabaseBackendException, SQLException {
+               // Trace message
+               this.getLogger().trace("CALLED!"); //NOI18N
 
-               // Is it set?
-               if (choosen.isEmpty()) {
-                       // Is empty
-                       this.getLogger().debug(MessageFormat.format("product={0},choosen={1} - returning zero ...", product.getName(), choosen)); //NOI18N
-                       return 0.00f;
-               }
+               // Product frontend
+               this.productFrontend = new ProductDatabaseFrontend();
 
-               // Get amount
-               String amount = this.handleAmountFromRequestSession(product, request, session);
-               this.getLogger().debug(MessageFormat.format("product={0},amount={1}", product.getName(), amount)); //NOI18N
+               // Category frontend
+               this.categoryFrontend = new CategoryDatabaseFrontend();
 
-               // Must not be null
-               assert(amount instanceof String): "amount is null"; //NOI18N
+               // Trace message
+               this.getLogger().trace("EXIT!"); //NOI18N
+       }
 
-               // Is it empty?
-               if (amount.isEmpty() || "0".equals(amount)) { //NOI18N
-                       // Is empty
-                       this.getLogger().debug(MessageFormat.format("product={0},amount={1} - returning zero ...", product.getName(), amount)); //NOI18N
-                       return 0.00f;
+       /**
+        * Checks whether given category title is already used
+        *
+        * @param title Title of category to check
+        * @return Whether it has been found
+        */
+       private boolean isCategoryTitleUsed(final String title) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+               // categoryFrontend must be set
+               if (null == this.categoryFrontend) {
+                       // Abort here
+                       throw new NullPointerException("categoryFrontend is null");
                }
 
-               // Init variable
-               Integer value = null;
+               // Delegate to frontend
+               return this.categoryFrontend.isCategoryTitleUsed(title);
+       }
 
-               // Try it
-               try {
-                       // Get amount as integer
-                       value = Integer.valueOf(amount);
-               } catch (final NumberFormatException e) {
-                       // Bat input
-                       throw new IllegalArgumentException(e);
+       /**
+        * Checks if given product title is already used
+        * @param title Product title to check
+        * @return Whether the product title has already been used
+        */
+       private boolean isProductTitleUsed (final String title) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+               // categoryFrontend must be set
+               if (null == this.productFrontend) {
+                       // Abort here
+                       throw new NullPointerException("productFrontend is null");
                }
 
-               // Calculate price
-               float price = (product.getPrice() * value);
+               // Delegate to frontend
+               return this.productFrontend.isProductTitleUsed(title);
+       }
 
+       /**
+        * Checks if the product ordered?
+        *
+        * @param product Product instance
+        * @param session HttpSession instance
+        * @return Whether the product has been ordered
+        */
+       private boolean isProductOrdered (final Product product, final HttpSession session) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},price={1} - EXIT!", product.getName(), price)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
+
+               // Get session
+               Object isOrdered = this.getValueFromSession(product, session, SESSION_ORDERED);
+               this.getLogger().debug(MessageFormat.format("product={0},isOrdered={1}", product.getItemId(), isOrdered)); //NOI18N
 
-               // Then multiply it with price
-               return price;
+               // Return result
+               return ("true".equals(isOrdered)); //NOI18N
        }
 
        /**
-        * Checks whether the given product is choosen, request overules session.
+        * Somewhat setter in session
         *
         * @param product Product instance
-        * @param request Request instance
         * @param session Session instance
-        * @return Whether the product is choosen
+        * @param keyPart Key part to include in final key
+        * @param value Value to set
         */
-       @Override
-       public boolean isProductChoosen (final Product product, final HttpServletRequest request, final HttpSession session) {
+       private void setValueInSession (final Product product, final HttpSession session, final String keyPart, final Object value) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
-
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
-               }
-
-               // Get choosen
-               String choosen = this.handleChooseFromRequestSession(product, request, session);
-               this.getLogger().debug(MessageFormat.format("product={0},choosen={1}", product.getName(), choosen)); //NOI18N
-
-               // Must not be null
-               assert(choosen instanceof String): "choosen is null"; //NOI18N
-
-               // Is it not choosen?
-               if (choosen.isEmpty()) {
-                       // Not choosen
-                       return false;
-               }
-
-               // Get amount
-               String amount = this.handleAmountFromRequestSession(product, request, session);
+               this.getLogger().trace(MessageFormat.format("product={0},session={1},keyPart={2},value={3} - CALLED!", product, session, keyPart, value)); //NOI18N
 
-               // Must not be null
-               assert(amount instanceof String): "amount is not set"; //NOI18N
+               // Set it synced
+               this.getLogger().debug(MessageFormat.format("Setting value={0} for product={1},keyPart={2}", value, product.getItemId(), keyPart)); //NOI18N
+               this.setValueInSession(session, String.format(HTTP_PARAM_MASK, keyPart, product.getItemId()), value);
 
                // Trace message
-               this.getLogger().trace(MessageFormat.format("amount={0} - EXIT!", amount)); //NOI18N
-
-               // Must not be empty and not 0
-               return (!amount.isEmpty() && !"0".equals(amount)); //NOI18N
+               this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Calculates total price of all choosen products
+        * Adds given category data from request to database
         *
         * @param request Request instance
-        * @param session Session instance
-        * @return Total price of all choosen products
         */
        @Override
-       public float calculateTotalPrice (final HttpServletRequest request, final HttpSession session) {
+       public void doAdminAddCategory (final HttpServletRequest request) throws ServletException, CategoryTitleAlreadyUsedException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("request={0},session={1} - CALLED!", request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("request={0} - CALLED!", request)); //NOI18N
 
-               // Is product and session set?
-               if (request == null) {
-                       // Not set
+               // request must not be null
+               if (null == request) {
+                       // Is null
                        throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
                }
 
-               // Init total price
-               float totalPrice = 0.00f;
+               // Get all fields
+               String title = request.getParameter(CategoryFrontend.COLUMN_TITLE);
+               String parent = request.getParameter(CategoryFrontend.COLUMN_PARENT);
 
-               // "Walk" over all products
-               for (final Product product : this.getProducts()) {
-                       // Is this choosen?
-                       if (this.isProductChoosen(product, request, session)) {
-                               // Then add product's total price
-                               this.getLogger().debug(MessageFormat.format("Calling getTotalPositionPriceFromRequestSession({0},request,session) ...", product.getName())); //NOI18N
-                               totalPrice += this.getTotalPositionPriceFromRequestSession(product, request, session);
+               // Debug message
+               this.getLogger().debug(MessageFormat.format("title={0},parent={1}", title, parent)); //NOI18N
+
+               // Init variables for casting
+               Integer id = 0;
+
+               // Check all fields
+               if (null == title) {
+                       // "title" not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", CategoryFrontend.COLUMN_TITLE)); //NOI18N
+               } else if (title.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", CategoryFrontend.COLUMN_TITLE)); //NOI18N
+               } else if ((parent != null) && (!parent.isEmpty())) {
+                       // "parent" is set, so check it
+                       try {
+                               id = Integer.parseInt(parent);
+                       } catch (final NumberFormatException e) {
+                               // Not valid number
+                               throw new IllegalArgumentException(e);
                        }
-                       this.getLogger().debug(MessageFormat.format("product={0},totalPrice={1}", product.getName(), totalPrice)); //NOI18N
                }
 
-               // Trace message
-               this.getLogger().trace(MessageFormat.format(" totalPrice={0} - EXIT!", totalPrice)); //NOI18N
+               try {
+                       // Try to check if title is used already
+                       if (this.isCategoryTitleUsed(title)) {
+                               // Title already used
+                               throw new CategoryTitleAlreadyUsedException(request);
+                       }
+               } catch (final IOException | SQLException | BadTokenException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
+               }
 
-               // Return total price
-               return totalPrice;
+               try {
+                       // The category is not found, so add it to database
+                       this.categoryFrontend.addCategory(title, id);
+               } catch (final SQLException | IOException ex) {
+                       // Continue to throw it
+                       throw new ServletException(ex);
+               }
+
+               // Trace message
+               this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Calculates total amount of all choosen products
+        * Adds given product data from request to database
         *
         * @param request Request instance
-        * @param session Session instance
-        * @return Total amount of all choosen products
         */
        @Override
-       public int calculateTotalAmount (final HttpServletRequest request, final HttpSession session) {
+       public void doAdminAddProduct (final HttpServletRequest request) throws ServletException, ProductTitleAlreadyUsedException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("request={0},session={1} - CALLED!", request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("request={0} - CALLED!", request)); //NOI18N
 
-               // Is product and session set?
-               if (request == null) {
-                       // Not set
+               // request must not be null
+               if (null == request) {
+                       // Is null
                        throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
                }
 
-               // Init total price
-               int totalAmount = 0;
+               // Get title, price and category id
+               String title = request.getParameter(ProductFrontend.COLUMN_TITLE);
+               String price = request.getParameter(ProductFrontend.COLUMN_PRICE);
+               String category = request.getParameter(ProductFrontend.COLUMN_CATEGORY);
+               String available = request.getParameter(ProductFrontend.COLUMN_AVAILABLE);
 
-               // "Walk" over all products
-               for (final Product product : this.getProducts()) {
-                       // Is this choosen?
-                       if (this.isProductChoosen(product, request, session)) {
-                               // Then add ordered amount
-                               this.getLogger().debug(MessageFormat.format("Counting {0} ...", product.getName())); //NOI18N
+               // Debug message
+               this.getLogger().debug(MessageFormat.format("title={0},price={1},category={2},available={3}", title, price, category, available)); //NOI18N
+
+               // Variables for converting
+               Long id = null;
+               Float p = null;
+
+               // Check all fields
+               if (null == title) {
+                       // "title" not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", ProductFrontend.COLUMN_TITLE)); //NOI18N
+               } else if (title.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", ProductFrontend.COLUMN_TITLE)); //NOI18N
+               } else if (null == price) {
+                       // "price" not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", ProductFrontend.COLUMN_PRICE)); //NOI18N
+               } else if (price.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", ProductFrontend.COLUMN_PRICE)); //NOI18N
+               } else if (null == category) {
+                       // "title" not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", ProductFrontend.COLUMN_CATEGORY)); //NOI18N
+               } else if (category.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", ProductFrontend.COLUMN_CATEGORY)); //NOI18N
+               } else if (null == available) {
+                       // "title" not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", ProductFrontend.COLUMN_AVAILABLE)); //NOI18N
+               } else if (available.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", ProductFrontend.COLUMN_AVAILABLE)); //NOI18N
+               } else if ((!"true".equals(available)) && (!"false".equals(available))) { //NOI18N
+                       // Invalid value
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is invalid: {1}", ProductFrontend.COLUMN_AVAILABLE, available)); //NOI18N
+               }
 
-                               // Getting amount
-                               String amount = this.getAmountFromSession(product, session);
+               // Parse numbers
+               try {
+                       id = Long.parseLong(category);
+                       p = Float.parseFloat(price);
+               } catch (final NumberFormatException e) {
+                       // Not valid number
+                       throw new IllegalArgumentException(e);
+               }
 
-                               // Add it up
-                               this.getLogger().debug(MessageFormat.format("amount={0}", amount)); //NOI18N
-                               totalAmount += Integer.valueOf(amount);
+               // Parse boolean
+               Boolean a = Boolean.parseBoolean(available);
+
+               // Test on product title
+               try {
+                       // Try to check if title is used already
+                       if (this.isProductTitleUsed(title)) {
+                               // Title already used
+                               throw new ProductTitleAlreadyUsedException(request);
                        }
-                       this.getLogger().debug(MessageFormat.format("product={0},totalAmount={1}", product.getName(), totalAmount)); //NOI18N
+               } catch (final IOException | SQLException | BadTokenException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
                }
 
-               // Trace message
-               this.getLogger().trace(MessageFormat.format("totalAmount={0} - EXIT!", totalAmount)); //NOI18N
+               try {
+                       // The product is not found, so add it to database
+                       this.productFrontend.addProduct(title, p, id, a);
+               } catch (final SQLException | IOException ex) {
+                       // Continue to throw it
+                       throw new ServletException(ex);
+               }
 
-               // Return total price
-               return totalAmount;
+               // Trace message
+               this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Some "getter" for HTML code 'checked="checked"' if the product is choosen
+        * Generates link HTML code for given category's parent id, if set. This
+        * link then points to products.jsp?category_id=x
         *
-        * @param product Product instance
-        * @param request Request instance
-        * @param session Session instance
-        * @return Whether the product is choosen
+        * @param category Category instance
+        * @return HTML code
         */
        @Override
-       public String getCheckedHtmlFromProduct (final Product product, final HttpServletRequest request, final HttpSession session) {
+       public String generateLinkForParent (final Category category) {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},request={1},session={2} - CALLED!", product, request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("category={0} - CALLED!", category)); //NOI18N
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // category must not be null
+               if (null == category) {
+                       // Is null
+                       throw new NullPointerException("category is null"); //NOI18N
                }
 
-               // First let's check if the product is choosen
-               if (this.isProductChoosen(product, request, session)) {
-                       // Trace message
-                       this.getLogger().trace("Returning checked=\"checked\" - EXIT!"); //NOI18N
-
-                       // Is choosen
-                       return "checked=\"checked\""; //NOI18N
-               } else {
-                       // Trace message
-                       this.getLogger().trace("Returning empty string - EXIT!"); //NOI18N
+               // Get parent id
+               Long parent = category.getParent();
 
-                       // Not choosen
-                       return ""; //NOI18N
+               // Is the id set?
+               if (parent > 0) {
+                       // Product HTML code for link
+                       throw new UnsupportedOperationException(MessageFormat.format("parent={0} - Unfinished!", parent)); //NOI18N
                }
+
+               // No parent set
+               return "Keine";
        }
 
-       /**
-        * Some "getter" for HTML code 'disabled="disabled"' for e.g. submit buttons
-        *
-        * @param request Request instance
-        * @param session Session instance
-        * @return Whether the product is choosen
-        */
        @Override
-       public String getDisabledHtmlFromSession (final HttpServletRequest request, final HttpSession session) {
+       public String getPrintableProduktCategory (final Product product) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("request={0},session={1} - CALLED!", request, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("product={0} - CALLED!", product)); //NOI18N
 
-               // Is product and session set?
-               if (request == null) {
-                       // Not set
-                       throw new NullPointerException("request is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // product must not be null
+               if (null == product) {
+                       // Abort here
+                       throw new NullPointerException("product is null"); //NOI18N
                }
 
-               // Is something selected?
-               if (this.calculateTotalAmount(request, session) > 0) {
-                       // Trace message
-                       this.getLogger().trace("Returning empty string - EXIT!"); //NOI18N
+               // Declare category
+               Category category;
 
-                       // Something has been choosen
-                       return ""; //NOI18N
-               } else {
-                       // Trace message
-                       this.getLogger().trace("Returning disabled=\"disabled\" - EXIT!"); //NOI18N
+               try {
+                       // Get Category instance from product over the frontend
+                       category = this.categoryFrontend.getCategory(product);
+               } catch (final IOException | SQLException | BadTokenException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
+                       throw new ServletException(ex);
+               }
 
-                       // Nothing choosen yet
-                       return "disabled=\"disabled\""; //NOI18N
+               // Debug message
+               this.getLogger().debug(MessageFormat.format("category={0}", category)); //NOI18N
+
+               String title = null;
+               try {
+                       // Now get title from it and return it
+                       title = category.getDecodedTitle();
+               } catch (final UnsupportedEncodingException ex) {
+                       // Continue to throw as cause
+                       throw new ServletException(ex);
                }
+
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("title={0} - EXIT!", title)); //NOI18N
+
+               // Return it
+               return title;
        }
 
        /**
-        * Marks given product as ordered in session
-        *
-        * @param product Product to mark as ordered
-        * @param session Session instance
+        * Checks if product's title is already used.
+        * 
+        * @param request Request instance
+        * @return Whether the product title is already used
+        * @throws java.io.IOException If any IO error occurs
+        * @throws org.mxchange.jcore.exceptions.BadTokenException If a bad token was found in a file-based database backend's file ... ;-)
+        * @throws java.sql.SQLException If any SQL error occurs
+        * @throws org.mxchange.jcore.exceptions.CorruptedDatabaseFileException If the database file is damaged
+        * @throws java.lang.NoSuchMethodException If a method was not found
+        * @throws java.lang.IllegalAccessException If the method cannot be accessed
+        * @throws java.lang.reflect.InvocationTargetException Any other problems?
         */
-       @Override
-       public void markProductAsOrdered(final Product product, final HttpSession session) {
+       private boolean isProductTitleUsed (final HttpServletRequest request) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("request={0} - CALLED!", request)); //NOI18N
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // Init title
+               String title = request.getParameter(ProductFrontend.COLUMN_TITLE);
+
+               // request must not be null and "title" must be found and non-empty
+               if (null == request) {
+                       // Abort here
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == title) {
+                       // title is not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", ProductFrontend.COLUMN_TITLE)); //NOI18N
+               } else if (title.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", ProductFrontend.COLUMN_TITLE)); //NOI18N
                }
 
-               // Mark it as ordered by setting flag
-               this.getLogger().debug(MessageFormat.format("Marking product={0} as ordered.", product.getName())); //NOI18N
-               this.setValueInSession(product, session, SESSION_ORDERED, "true"); //NOI18N
+               // Default is not used
+               boolean isUsed = this.isProductTitleUsed(title);
 
                // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
+               this.getLogger().trace(MessageFormat.format("isUsed={0} - EXIT!", isUsed)); //NOI18N
+
+               // Return it
+               return isUsed;
        }
 
        /**
-        * Unmarks given product as ordered in session
-        *
-        * @param product Product to unmark as ordered
-        * @param session Session instance
+        * Handles admin form requests
+        * @param request Request instance
+        * @param response Response instance
+        * @throws ServletException If something unexpected happened
         */
        @Override
-       public void unmarkProductAsOrdered(final Product product, final HttpSession session) {
+       public void doAdminHandleProductForms (final HttpServletRequest request, final HttpServletResponse response) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
+               this.getLogger().trace(MessageFormat.format("request={0},response={1} - CALLED!", request, response)); //NOI18N
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // request and response must both be set
+               if (null == request) {
+                       // request is null
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == response) {
+                       // response is null
+                       throw new NullPointerException("response is null"); //NOI18N
                }
 
-               // Mark it as ordered by setting flag
-               this.getLogger().debug(MessageFormat.format("Unmarking product={0} as ordered.", product.getName())); //NOI18N
-               this.clearSessionAttribute(product, session, SESSION_ORDERED);
+               // Try this operations
+               try {
+                       // Is it post?
+                       if ("POST".equals(request.getMethod())) { //NOI18N
+                               // Is "add/edit/delete" set?
+                               if (request.getParameter("add") != null) { //NOI18N
+                                       // Is it already added?
+                                       if (this.isProductTitleUsed(request)) {
+                                               // Debug message
+                                               this.getLogger().debug("Already used, redirecting ..."); //NOI18N
+
+                                               // Already added, so redirect here, else a ServletException will be thrown
+                                               response.sendRedirect(String.format("%s/admin/product.jsp?already=1", request.getContextPath())); //NOI18N
+                                       } else {
+                                               // Add new product
+                                               this.doAdminAddProduct(request);
+                                       }
+                               } else if (request.getParameter("edit") != null) { //NOI18N
+                                       // @TODO
+                               } else if (request.getParameter("delete") != null) { //NOI18N
+                                       // @TODO
+                               }
+
+                               // Redirect to proper URL
+                               // @TODO Commented out for developing:
+                               //response.sendRedirect(request.getContextPath() + "/finished.jsp");
+                       }
+               } catch (final IOException | SQLException | BadTokenException | CorruptedDatabaseFileException | ProductTitleAlreadyUsedException | NoSuchMethodException | IllegalAccessException | InvocationTargetException | IllegalArgumentException ex) {
+                       // Throw it as cause
+                       throw new ServletException(ex);
+               }
 
                // Trace message
                this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Some getter for printable value from session or an empty string for null.
-        *
-        * @param session Session instance
-        * @param key Key to get
-        * @return Value from key, empty string for null
+        * Handles admin form requests
+        * @param request Request instance
+        * @param response Response instance
+        * @throws ServletException If something unexpected happened
         */
        @Override
-       public Object getPrintableValeFromSession (final HttpSession session, final String key) {
+       public void doAdminHandleCategoryForms (final HttpServletRequest request, final HttpServletResponse response) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("session={0},key={1} - CALLED", session, key));
+               this.getLogger().trace(MessageFormat.format("request={0},response={1} - CALLED!", request, response)); //NOI18N
 
-               // Are both parameter not null?
-               if (session == null) {
-                       // Abort here
-                       throw new NullPointerException("session is null");
-               } else  if (key == null) {
-                       // Abort here
-                       throw new NullPointerException("key is null");
+               // request and response must both be set
+               if (null == request) {
+                       // request is null
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == response) {
+                       // response is null
+                       throw new NullPointerException("response is null"); //NOI18N
                }
 
-               // Now get it
-               Object value = this.getValueFromSession(session, key);
-
-               // Debug message
-               this.getLogger().debug(MessageFormat.format("value={0}", value));
+               // Try this operations
+               try {
+                       // Is it post?
+                       if ("POST".equals(request.getMethod())) { //NOI18N
+                               // Is "add/edit/delete" set?
+                               if (request.getParameter("add") != null) { //NOI18N
+                                       // Is the category title already used?
+                                       if (this.isCategoryTitleUsed(request)) {
+                                               // Debug message
+                                               this.getLogger().debug("Already used, redirecting ..."); //NOI18N
+
+                                               // Already added, so redirect here, else a ServletException will be thrown
+                                               response.sendRedirect(String.format("%s/admin/category.jsp?already=1", request.getContextPath())); //NOI18N
+                                       } else {
+                                               // Add new category
+                                               this.doAdminAddCategory(request);
+                                       }
+                               } else if (request.getParameter("edit") != null) { //NOI18N
+                                       // @TODO
+                               } else if (request.getParameter("delete") != null) { //NOI18N
+                                       // @TODO
+                               }
+
+                               // Redirect to proper URL
+                               // @TODO Commented out for developing:
+                               //response.sendRedirect(request.getContextPath() + "/finished.jsp");
+                       }
+               } catch (final IOException | SQLException | BadTokenException | CorruptedDatabaseFileException | CategoryTitleAlreadyUsedException | NoSuchMethodException | IllegalAccessException | InvocationTargetException | IllegalArgumentException ex) {
+                       // Throw it as cause
+                       throw new ServletException(ex);
+               }
 
                // Trace message
-               this.getLogger().trace(MessageFormat.format("Calling this.convertNullToEmpty({0}) ... - EXIT!", value));
-
-               // Return actual value
-               return this.convertNullToEmpty(value);
+               this.getLogger().trace("EXIT!"); //NOI18N
        }
 
        /**
-        * Gets an array of products from product iterator and unmarks them as ordered
+        * Checks if category's title is already used.
         * 
-        * @param session HttpSession instance
-        * @return Unmarked products
+        * @param request Request instance
+        * @return Whether the product title is already used
+        * @throws java.io.IOException If any IO error occurs
+        * @throws org.mxchange.jcore.exceptions.BadTokenException If a bad token was found in a file-based database backend's file ... ;-)
+        * @throws java.sql.SQLException If any SQL error occurs
+        * @throws org.mxchange.jcore.exceptions.CorruptedDatabaseFileException If the database file is damaged
+        * @throws java.lang.NoSuchMethodException If a method was not found
+        * @throws java.lang.IllegalAccessException If the method cannot be accessed
+        * @throws java.lang.reflect.InvocationTargetException Any other problems?
         */
-       @Override
-       public Product[] getUnmarkedProducts (final HttpSession session) {
-               // Init array
-               Product[] array = this.getProducts();
+       private boolean isCategoryTitleUsed (final HttpServletRequest request) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("request={0} - CALLED!", request)); //NOI18N
 
-               // Unmark are all as ordered
-               for (final Product product : array) {
-                       this.unmarkProductAsOrdered(product, session);
+               // Init title
+               String title = request.getParameter(CategoryFrontend.COLUMN_TITLE);
+
+               // request must not be null and "title" must be found and non-empty
+               if (null == request) {
+                       // Abort here
+                       throw new NullPointerException("request is null"); //NOI18N
+               } else if (null == title) {
+                       // title is not set
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is not set.", CategoryFrontend.COLUMN_TITLE)); //NOI18N
+               } else if (title.isEmpty()) {
+                       // Is left empty
+                       throw new IllegalArgumentException(MessageFormat.format("{0} is empty.", CategoryFrontend.COLUMN_TITLE)); //NOI18N
                }
 
-               // Return finished array
-               return array;
-       }
+               // Default is not used
+               boolean isUsed = this.isCategoryTitleUsed(title);
 
-       /**
-        * Some "getter" for a an array of all products
-        * 
-        * @return Unmarked products
-        */
-       @Override
-       public Product[] getProducts () {
-               return (Product[]) this.products.values().toArray();
+               // Trace message
+               this.getLogger().trace(MessageFormat.format("isUsed={0} - EXIT!", isUsed)); //NOI18N
+
+               // Return it
+               return isUsed;
        }
 
-       /**
-        * Marks given product as choosen in session
-        *
-        * @param product Product to mark as ordered
-        * @param session Session instance
-        */
        @Override
-       public void markProductAsChoosen(final Product product, final HttpSession session) {
+       public Product getProduct (final AddableBasketItem item) throws ServletException {
                // Trace message
-               this.getLogger().trace(MessageFormat.format("product={0},session={1} - CALLED!", product, session)); //NOI18N
+               this.getLogger().trace("item=" + item + " - CALLED!");
 
-               // Is product and session set?
-               if (product == null) {
-                       // Not set
-                       throw new NullPointerException("product is null"); //NOI18N
-               } else if (session == null) {
-                       // Not set
-                       throw new NullPointerException("session is null"); //NOI18N
+               // item should not be null
+               if (null == item) {
+                       // Abort here
+                       throw new NullPointerException("item is null");
+               } else if (null == this.productFrontend) {
+                       // Abort here
+                       throw new NullPointerException("productFrontend is null");
                }
 
-               // Mark it as ordered by setting flag
-               this.getLogger().debug(MessageFormat.format("Marking product={0} as choosen.", product.getName())); //NOI18N
-               this.setValueInSession(product, session, HTTP_PARAM_CHOOSE, "1");
+               // Init product instance
+               Product product = null;
+
+               try {
+                       // Call frontend
+                       product = this.productFrontend.getProduct(item);
+               } catch (final SQLException | IOException | BadTokenException | CorruptedDatabaseFileException | NoSuchMethodException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
+                       // Continue to throw
+                       throw new ServletException(ex);
+               }
 
                // Trace message
-               this.getLogger().trace("EXIT!"); //NOI18N
+               this.getLogger().trace("product=" + product + " - EXIT!");
+
+               // Return it
+               return product;
        }
 }