Getting information regarding the client browser using JSP

package de.hunsicker.http.util;


import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class Browser extends HttpServlet
{
  protected HttpServletRequest request;
  protected HttpSession session;

  protected String userAgent;
  protected String company;          // Firmenname des Herstellers
  protected String name;             // Bezeichnung des Browsers
  protected String version;          // Version
  protected String mainVersion;      // Hauptversion
  protected String minorVersion;     // Unterversion
  protected String os;               // Betriebssystem
  protected String language = "de";  // Sprachcode Standard
  protected Locale locale;           // Locale-Objekt mit den aktuellen
                                     // Spracheinstellungen

  private Hashtable supportedLanguages; // Untersttzte Sprachen

  public Browser(HttpServletRequest request, HttpSession session)
  {
    this.initialize();
    this.request = request;
    this.session = session;

    this.setUserAgent(this.request.getHeader("User-Agent"));
    this.setCompany();
    this.setName();
    this.setVersion();
    this.setMainVersion();
    this.setMinorVersion();
    this.setOs();
    this.setLanguage();
    this.setLocale();
  }

  public void initialize()
  {
    this.supportedLanguages = new Hashtable(2);
      this.supportedLanguages.put("en", "");
      this.supportedLanguages.put("de", "");
  }

  public void setUserAgent(String httpUserAgent)
  {
    this.userAgent = httpUserAgent.toLowerCase();
  }

  private void setCompany()
  {
    if (this.userAgent.indexOf("MSIE") > -1)
    {
      this.company = "Microsoft";
    }
    else if (this.userAgent.indexOf("opera") > -1)
    {
      this.company = "Opera Software";
    }
    else if (this.userAgent.indexOf("mozilla") > -1)
    {
      this.company = "Netscape Communications";
    }
    else
    {
      this.company = "unknown";
    }
  }

  /**
   * Liefert den Firmennamen des Herstellers des verwendeten Browsers.
   */
  public String getCompany()
  {
    return this.company;
  }

  private void setName()
  {
    if (this.company == "Microsoft")
    {
      this.name = "Microsoft Internet Explorer";
    }
    else if (this.company == "Netscape Communications")
    {
      this.name = "Netscape Navigator";
    }
    else if (this.company == "Operasoftware")
    {
      this.name = "Operasoftware Opera";
    }
    else
    {
      this.name = "unknown";
    }
  }

  /**
   * Liefert den Namen des verwendeten Browsers.
   */
  public String getName()
  {
    return this.name;
  }

  private void setVersion()
  {
    int tmpPos;
    String tmpString;

    if (this.company == "Microsoft")
    {
      String str = this.userAgent.substring(this.userAgent.indexOf("msie") + 5);
      this.version = str.substring(0, str.indexOf(";"));
    }
    else
    {
     tmpString = (this.userAgent.substring(tmpPos = (this.userAgent.indexOf("/")) + 1,
       tmpPos + this.userAgent.indexOf(" "))).trim();
     this.version = tmpString.substring(0, tmpString.indexOf(" "));
    }
  }

  /**
   * Liefert die Versionsnummer des verwendeten Browsers.
   */
  public String getVersion()
  {
    return this.version;
  }

  private void setMainVersion()
  {
    this.mainVersion = this.version.substring(0, this.version.indexOf("."));
  }

  /**
   * Liefert die Hauptversionsnummer des verwendeten Browsers.
   */
  public String getMainVersion()
  {
    return this.mainVersion;
  }

  private void setMinorVersion()
  {
    this.minorVersion = this.version.substring(this.version.indexOf(".") + 1).trim();
  }

  /**
   * Liefert die Unterversionsnummer des verwendeten Browsers.
   */
  public String getMinorVersion()
  {
    return this.minorVersion;
  }

  private void  setOs()
  {
     if (this.userAgent.indexOf("win") > -1)
     {
          if (this.userAgent.indexOf("windows 95") > -1 || this.userAgent.indexOf("win95") > -1)
          {
            this.os = "Windows 95";
          }
          if (this.userAgent.indexOf("windows 98") > -1 || this.userAgent.indexOf("win98") > -1)
          {
            this.os = "Windows 98";
          }
          if (this.userAgent.indexOf("windows nt") > -1 || this.userAgent.indexOf("winnt") > -1)
          {
            this.os = "Windows NT";
          }
          if (this.userAgent.indexOf("win16") > -1 || this.userAgent.indexOf("windows 3.") > -1)
          {
            this.os = "Windows 3.x";
          }
     }
     else if (this.userAgent.indexOf("Mac") > -1 )
     {
          if (this.userAgent.indexOf("Mac_PowerPC") > -1 || this.userAgent.indexOf("Mac_PPC") > -1)
          {
            this.os = "Macintosh Power PC";
          }
          else if (this.userAgent.indexOf("Macintosh") > -1)
          {
            this.os = "Macintosh";
          }
          else
          {
              this.os = "Unknown Mac";
          }
     }
  }

  /**
   * Liefert den Namen des Betriebssystems.
   */
  public String getOs()
  {
    return this.os;
  }

  private void setLanguage()
  {
    String prefLanguage = this.request.getHeader("Accept-Language");

    if (prefLanguage != null)
    {
      String language = null;
      StringTokenizer st = new StringTokenizer(prefLanguage, ",");

      int elements = st.countTokens();

      for (int idx = 0; idx < elements; idx++)
      {
          if (this.supportedLanguages.containsKey((language = st.nextToken())))
          {
            this.language = this.parseLocale(language);
          }
        }
    }
  }

  /*
   * Hilfsfunktion fr setLanguage().
   */
  private String parseLocale(String language)
  {
    StringTokenizer st = new StringTokenizer(language, "-");

    if (st.countTokens() == 2)
    {
      return st.nextToken();
    }
    else
    {
      return language;
    }
  }

  /**
   * Liefert das Länderkürzel der vom Benutzer
   * bevorzugten Sprache.
   */
  public String getLanguage()
  {
    return this.language;
  }

  private void setLocale()
  {
    this.locale = new Locale(this.language, "");
  }

  /**
   * Liefert ein Locale-Objekt mit der Sprach-Prferenz des verwendeten Browsers
   */
  public Locale getLocale()
  {
    return this.locale;
  }
}