browsercore.java

一个用 java写的wap浏览器 对于浏览器感兴趣起的可以看看咯

    *     BrowserCore creates an instance of TemplateParser and parses the
    *     template.
    * <li>Sets the CardParser and TemplateParser objects to null.
    * <li>If errors were encountered while parsing the card or template, a WML
    *     deck with an error message is created and passed as a parameter to
    *     DisplayEngine.drawCard(). If there were no errors, the parsed card is
    *     passed as a parameter to DisplayEngine.drawCard().
    * </ul>
    */
    public synchronized void processEventsLoop(int intEventID)
        throws IOException
    {
      // Private variables
      /** The binary encoded WML deck. */
      byte[]          bytDeck = null;
      /**
       * Flags whether errors were encountered in the parsing of the card or
       * template.
       */
      boolean         c_bolNoErrors;
      /** Flags if the user has navigated to a URL yet. */
      boolean         bolFirstURL = true;
      /** Reference to the event instance that is being processed. */
      EventInstance   clsEI;
      /** Reference to the GO event instance that is being processed. */
      GoEventInstance clsGoEI = null;
      /** The parser that parses cards. */
      CardParser      clsCardParser;
      /**
       * Holds the previous URL that was navigated to. This is used for adding
       * URLs to the history.
       */
      String          strPrevURL = null;
      c_clsRTime.gc();

      while (intEventID != 0)
      {
        c_bolNoErrors = true;

        // Get the event instance that matched the returned event
        clsEI = (EventInstance)
          c_clsEventManagement.getEventInstance(intEventID, c_clsBrowserContext);

        // And execute the event instance
        switch (clsEI.getEventType())
        {
          case 1: // go

            clsGoEI = (GoEventInstance)clsEI;

            // Push the new card onto the history stack
            if (strPrevURL != null && !strPrevURL.equals(""))
            {
              if (!strPrevURL.startsWith("http://"))
                c_clsBrowserContext.pushCard("http://" + strPrevURL);
              else
                c_clsBrowserContext.pushCard(strPrevURL);
            } // if
            strPrevURL = null;

            // See if we need to get a new deck
            if (c_clsCurrentDeck == null)
            {
              c_clsCurrentDeck = new CurrentDeck();
              c_clsNetLayer.c_clsCurrDeck = c_clsCurrentDeck;
            } // if

            String clsStrURL = clsGoEI.getURL();

            /* Set "strPrevURL" so that when a GO is next executed, this URL
             * will be pushed onto the history. If this is the first URL for the
             * session, we want to add the URL entered by the user to the history.
             */
            if (bolFirstURL)
            {
              strPrevURL = clsStrURL;
              bolFirstURL = false;
            }
            else
              strPrevURL = c_clsCurrentDeck.getAbsoluteURL();

            if (c_clsCurrentDeck.requireNewDeck(
              c_clsBrowserCore.subVars(clsStrURL)))
            {
              bytDeck = processNewDeck(
                c_clsBrowserCore.subVars(c_clsCurrentDeck.getAbsoluteURL()),
                                         clsGoEI);
            } // if

            // Kill Event Management now that we are a in new process
            c_clsEventManagement = null;
            c_clsEventManagement = new EventManagement();

            clsCardParser = new CardParser();
            clsCardParser.init(c_clsBrowserCore,
                               c_clsCurrentDeck,
                               c_clsEventManagement,
                               c_clsBrowserContext);
            c_clsVecCard = new Vector(1,1);

            // Parse the card. Try-catch used for exception processing.
            try
            {
              intEventID = clsCardParser.parse(
                         c_clsCurrentDeck.getFragmentID(),
                         c_clsVecCard,
                         c_clsVecDosInCard,
                         WmlTags.ONENTER_FORWARDS);
            }
            catch (J2WapException e)
            {
              /*
               * Convert the contents of the card vector to a single string so
               * that it can be placed in one element of the card vector.
               */
              String clsStrCard = c_clsVecCard.toString();
              c_clsVecCard.removeAllElements();
              c_clsVecCard.addElement("<card>");
              c_clsVecCard.addElement("<p>");
              c_clsVecCard.addElement(
                "Malformed card. The following error was encountered: ");
              c_clsVecCard.addElement(e.getMessage());
              c_clsVecCard.addElement("</p>");
              c_clsVecCard.addElement("*** Contents of parsed card:");
              c_clsVecCard.addElement(clsStrCard);

              // </card> is added later on.
              c_bolNoErrors = false;
              intEventID = WmlTags.NO_EVENT;
              setOntimerId(0);
            } // try-catch

            /* If no intrinsic event was fired and the deck has a tempate,
             * parse it.
             */
            if (c_bolNoErrors && intEventID == WmlTags.NO_EVENT &&
                c_clsCurrentDeck.hasTemplate())
            {
              try
              {
                TemplateParser clsTemlateParser = new TemplateParser ();
                clsTemlateParser.init(c_clsBrowserCore,
                                      c_clsCurrentDeck,
                                      c_clsEventManagement,
                                      c_clsBrowserContext);
                intEventID = clsTemlateParser.parse(
                                      c_clsCurrentDeck.getFragmentID(),
                                      c_clsVecCard,
                                      c_clsVecDosInCard,
                                      WmlTags.ONENTER_FORWARDS);
                clsTemlateParser = null;
              }
              catch (J2WapException e)
              {
                /* Convert the contents of the card vector to a single string so
                 * that it can be placed in one element of the card vector.
                 */
                String clsStrCard = c_clsVecCard.toString();
                c_clsVecCard.removeAllElements();
                c_clsVecCard.addElement("<card>");
                c_clsVecCard.addElement("<p>");
                c_clsVecCard.addElement(
                  "Malformed card. The following error was encountered: ");
                c_clsVecCard.addElement(e.getMessage());
                c_clsVecCard.addElement("</p>");
                c_clsVecCard.addElement("*** Contents of parsed card:");
                c_clsVecCard.addElement(clsStrCard);

                // </card> is added later on.
                c_bolNoErrors = false;
                intEventID = WmlTags.NO_EVENT;
                setOntimerId(0);
              } // try-catch
            } // if

            // Add the end of card tag to the card vector.
            c_clsVecCard.addElement(WmlTags.END_TAG_CARD);

            // Garbage collection.
            clsCardParser = null;
            c_clsRTime.gc ();

            // Now delete content from do vector
            c_clsVecDosInCard.removeAllElements ();

            /**
             * Call draw card if we don't already have an event
             * which is the event id of the ontimer event.
             */
            if (intEventID == WmlTags.NO_EVENT)
              intEventID = c_clsDisplayEngine.drawCard(c_clsVecCard,
                                                       c_clsEventManagement,
                                                       c_intOntimerId);

            break;

          case 2: // prev

            /*
             * Previous will simply pop off the history URL,
             * And aregister that as the next go event
             */
            clsEI = null;
            if (c_clsBrowserCore.historyHasURLs())
            {
              strPrevURL = c_clsBrowserContext.popCard();
              intEventID = c_clsEventManagement.registerGo(strPrevURL,
                                                           false,
                                                           "GET",
                                                           null);
              // Stop the URL from being added to history when the GO is executed.
              strPrevURL = null;
            }
            else if (c_clsVecCard == null)
            {
              intEventID = c_clsDisplayEngine.drawCard(c_clsBrowserCore.c_clsStartWml,
                                                       c_clsEventManagement,
                                                       c_intOntimerId);
            }
            else
            {
              intEventID = c_clsDisplayEngine.drawCard(c_clsVecCard,
                                                       c_clsEventManagement,
                                                       c_intOntimerId);
            } // if-else

            break;

          case 3: // refresh

            /**
             * Refresh needs to redraw the card with the current vector
             */
            clsEI = null;
            intEventID = c_clsDisplayEngine.drawCard(c_clsVecCard,
                                                     c_clsEventManagement,
                                                     c_intOntimerId);
            break;

          case 4: // noop

            /**
             * We should NEVER actually terminate a function to perform
             * a noop event - they should be ignored, and normal ui
             * processing should continue.
             */
            System.exit(-1);
            break;

        } // switch

        // Call garbage collection after a major event
        Runtime.getRuntime().gc();
      } // While intEventID != 0
    } // processEventsLoop

    /**
     * Get the WML deck from the WAP gateway and save the bytecode in the
     * <code>CurrentDeck</code> object.
     * @param   in_clsDeckURL The absolute URL of the required WML deck.
     * @param   in_clsGoEvent The <code>GoEventInstance</code> that contains
     *                        details of the GO.
     * @return  The WML deck's bytecode.
     */
    private byte[] processNewDeck (String           in_clsDeckURL,
                                   GoEventInstance  in_clsGoEvent)
      throws IOException
    {
      String strPostfield =
        subVars(in_clsGoEvent.getPostfieldStr(c_clsBrowserContext));

      byte deckByteArr[] =  c_clsNetLayer.doConnection(
                            c_clsGateway,
                            in_clsDeckURL,
                            in_clsGoEvent.getMethod(),
                            1,
                            strPostfield);

      // Clear all variables in the browser context.
      c_clsBrowserContext.clearVariables();
      c_clsCurrentDeck.getDeck(deckByteArr, in_clsDeckURL);

      return deckByteArr;
    } // processNewDeck
  } // class ProcessEvents

} // class BrowserCore