headerfilter.java

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/*
 * @author                        : Neelesh
 * @Version                       : 1.0
 *
 * Development Environment        : Oracle9i JDeveloper
 * Name of the Application        : HeaderFilter.java
 * Creation/Modification History  :
 *
 * Neelesh      17-March-2003      Created
 *
 */
package oracle.otnsamples.vsm;

import java.io.IOException;

import java.security.Principal;

import java.util.Hashtable;
import java.util.Locale;
import java.util.ResourceBundle;

import javax.naming.InitialContext;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import oracle.otnsamples.util.Utilities;
import oracle.otnsamples.util.ServiceLocator;

import oracle.otnsamples.vsm.services.DataPopulator;
import oracle.otnsamples.vsm.services.DataPopulatorHome;
import oracle.otnsamples.vsm.services.MallNavigation;
import oracle.otnsamples.vsm.services.MallNavigationHome;
import oracle.otnsamples.vsm.services.data.Country;

import org.apache.struts.action.Action;


/**
 * This class is a filter for all requests. The filter is used to set the
 * header and footer for the requested page, based on the role of the user The
 * filter stores the user id in session for use by other actions. The filter
 * sets the Struts locale, based on user selection/browser locale.
 * @author Neelesh
 * @version 1.0
 */
public class HeaderFilter implements Filter {

  // Cache of locales
  private static Hashtable localeTable = new Hashtable();

  // Filter config
  private FilterConfig filterConfig = null;

  // Bundle containing header/footer info
  private ResourceBundle rb;

  // The character encoding for the application
  private String encoding;

  /**
   * Loads the resource bundle with name "uiresources"
   *
   * @param <b>filterConfig</b> Filter configuration
   */
  public void init(FilterConfig filterConfig) throws ServletException {
    this.filterConfig   = filterConfig;
    rb                  = ResourceBundle.getBundle("uiresources");
    encoding=  filterConfig.getInitParameter("encoding");
    // Populate data
    MallNavigationHome mallHome     = null;
    MallNavigation navigation       = null;
    DataPopulator populator         = null;
    DataPopulatorHome populatorHome = null;
    
    try {
      InitialContext ctx = new InitialContext();
      java.util.Properties props = Utilities.loadParams("Misc");
      JAASManager userManager =(JAASManager)Class.forName(props.
                         getProperty("jaas.manager", 
                        "oracle.otnsamples.vsm.OC4JJAASManager")).newInstance();

      userManager.init(filterConfig.getServletContext());
      ctx.rebind("java:/comp/env/UserManager",userManager);

      mallHome =
        (MallNavigationHome) ServiceLocator.getLocator().getService("MallNavigation");
      navigation = mallHome.create();

      // Check for presence of test data, by getting countries
      Country[] countries = navigation.getCountries();

      // if no countries, populate data
      if(countries == null || countries.length == 0) {
        populatorHome =
          (DataPopulatorHome) ServiceLocator.getLocator().getService("DataPopulator");
        populator = populatorHome.create();

        populator.populate();
      }
    } catch(Exception ex) {
      ex.printStackTrace();
    } finally {

      // Cleanup service beans
      try {
        if(navigation != null) {
          navigation.remove();
        }

        if(populator != null) {
          populator.remove();
        }
      } catch(Exception e) {
      }
    }

  }
  /**
   * Filter lifecycle method. Sets the config to null
   */
  public void destroy() {
    this.filterConfig = null;
  }
  /**
   * The method does the actual filtering work If there is a user logged in,
   * and the user is shopowner or shopuser, the corresponding header/footer
   * JSPs are set in request If the user has requested a locale change, the
   * session wide locale is changed to the requested locale If the user has
   * logged in, the user name is stored in session for use by other modules
   *
   * @param <b>request</b> -ServletRequest
   * @param <b>response</b> -ServletResponse
   * @param <b>chain</b> - Filter chain
   *
   * @throws <b>IOExcpetion</b>
   * @throws <b>ServletExcpetion</b>
   */
  public void doFilter(ServletRequest request, ServletResponse response,
                       FilterChain chain) throws IOException, 
                                                 ServletException {

    // Set the character encoding
    request.setCharacterEncoding("UTF8");
    HttpSession session = ((HttpServletRequest) request).getSession();
    // Find logged in user
    HttpServletRequest req = (HttpServletRequest) request;
    Principal principal    = req.getUserPrincipal();
    if(principal != null) {

      String userName = principal.getName();

      // Remove realm name and retain only user name
      userName =
        userName.substring(userName.indexOf('/') + 1, userName.length());

      // set appropriate header/footers, based on roles
      if(req.isUserInRole("shopuser")) {
        request.setAttribute("Header", rb.getString("user.HEADER"));
        request.setAttribute("Footer", rb.getString("user.FOOTER"));

        // set the user name in session
        if(session.getAttribute("userName") == null) {
          session.setAttribute("userName", userName);
        }
      } else if(req.isUserInRole("shopowner")) {
        request.setAttribute("Header", rb.getString("owner.HEADER"));
        request.setAttribute("Footer", rb.getString("owner.FOOTER"));

        // set the user name in session
        if(session.getAttribute("userName") == null) {
          session.setAttribute("userName", userName);
        }
      } else {

        // unknown user .So use default headers and footers
        request.setAttribute("Header", rb.getString("user.HEADER"));
        request.setAttribute("Footer", rb.getString("user.FOOTER"));
      }
    } else {

      // nobody has logged in. So use default header/footer
      request.setAttribute("Header", rb.getString("user.HEADER"));
      request.setAttribute("Footer", rb.getString("user.FOOTER"));
    }
    // Handle locales
    Locale requestedLocale = null;

    String lang = request.getParameter("lang");
    
    // If the user has requested for a specific language
    if(lang != null) {

      // check if the locale for the requested language is in the localetable
      requestedLocale = (Locale) localeTable.get(lang);
      
      // if not present, create a new locale and store it in the table
      if(requestedLocale == null) {
        // Locale is created with no country
        requestedLocale = new Locale(lang, "");
        localeTable.put(lang, requestedLocale);
      }

      // change current locale
      session.setAttribute(Action.LOCALE_KEY, requestedLocale);
      
    } else {
      if(session.getAttribute(Action.LOCALE_KEY) == null) {
        session.setAttribute(Action.LOCALE_KEY, request.getLocale());
        
      }
    }

    // forward to next filter/servlet in the chain
    chain.doFilter(request, response);
  }
}