Синхронизация responce в сервлете

//-----------------------------------------------
 
package usf_sm;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import usf_sm.page.*;
import usf_sm.storage.*;
import usf_sm.tools.Preferences;
import usf_sm.page.frames.*;
 
public class MainHandler
    extends HttpServlet /*implements SingleThreadModel*/ {
  private static final String CONTENT_TYPE = 'text/html; charset=windows-1251';
  private static final String CHARACTER_ENCODING = 'Cp1251';
  private RequestProcessor m_rp = null;
  private Vector m_legalUsers = new Vector();
  private String m_logonAddr = 'http://' + new Preferences().GetServer() + '/usf_sm/logon';
 
  //Initialize global variables
  public void init() throws ServletException {
    AbstractPage.init();
 
    // Init users !
    SysUser u = new SysUser('admin:admin', true, true);
    m_legalUsers.add(u);
    u = new SysUser('user:', true, false);
    m_legalUsers.add(u);
    u = new SysUser('guest:', true, false);
    m_legalUsers.add(u);
    //
  }
 
  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    go(request, response);
  }
 
  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    go(request, response);
  }
 
  public void go(HttpServletRequest request,
                 HttpServletResponse response) throws ServletException,
      IOException {
    response.setContentType(CONTENT_TYPE);
    request.setCharacterEncoding(CHARACTER_ENCODING);
    AbstractPage p = lookupPage(request, response);
//     if (p instanceof DummyPage) return;
    if (p != null) {
      p.generate();
    }
    else {
      response.getWriter().println('No reply on request ' +
                                   request.getRequestURL());
    }
  }
 
  private boolean isUserAdmin(String auth) {
    boolean ret = false;
    if (auth != null) {
      for (int i = 0; i < m_legalUsers.size(); i++) {
        SysUser u = (SysUser) m_legalUsers.get(i);
        String _userPassEncoded = auth.substring(6);
        if (u.isMe2(_userPassEncoded) == true) {
          ret = u.isAdmin();
        }
      }
    }
    return ret;
  }
 
  private boolean userAllowed(String auth) { //throws Exception {
    if (auth == null) {
      return false; // no auth
    }
 
    if (!auth.toUpperCase().startsWith('BASIC ')) {
      return false; // we only do BASIC
    }
 
    // Get encoded user and password, comes after 'BASIC '
    String userpassEncoded = auth.substring(6);
 
    // Decode it, using any base 64 decoder
    sun.misc.BASE64Decoder dec = new sun.misc.BASE64Decoder();
    String userpassDecoded = '';
    try {
      userpassDecoded = new String(dec.decodeBuffer(userpassEncoded));
      System.out.println('userpassDecoded=' + userpassDecoded);
    }
    catch (Exception e) {
      e.printStackTrace();
    }
 
    // Check our user list to see if that user and password are 'allowed'
    for (int i = 0; i < m_legalUsers.size(); i++) {
      SysUser u = (SysUser) m_legalUsers.get(i);
      if (u.isMe(userpassDecoded) == true) {
        return u.allowed();
      }
    }
    return false;
  }
 
  private boolean   e();
        break;
      case RequestProcessor.UPLOAD_PAGE:
        ret = new MainInvoker(request,response,m_rp.getParams(),false).GetUploadPage();
        break;
      case RequestProcessor.DO_UPLOAD:
        ret = new MainInvoker(request,response,m_rp.getParams(),false).DoUpload();
        break;
      case RequestProcessor.UPLOADED_DATA_PAGE:
        try {
          boolean adm = false;
          if (request.getHeader('Authorization') != null) {
            adm = isUserAdmin(request.getHeader('Authorization'));
          }
          if (!adm) {
            response.sendRedirect(m_logonAddr);
          }
          else {
            ret = new MainInvoker(request, response,m_rp.getParams(),adm).GetUploadedDataPage();
          }
        }
        catch (Exception e) {
          e.printStackTrace();
        }
        break;
      case RequestProcessor.PREV_TEMP_DATA:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).GetPrevTempData();
        break;
      case RequestProcessor.NEXT_TEMP_DATA:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).GetNextTempData();
        break;
      case RequestProcessor.DELETE_TEMP_DATA:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).DeleteTempData();
        break;
      case RequestProcessor.GET_PIC:
        new MainInvoker(request, response,m_rp.getParams(),false).GetPic();
        break;
      case RequestProcessor.VIEW_DWNL_DOC_PAGE:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).GetViewOrDownloadDocPage();
        break;
      case RequestProcessor.APPROVE_TEMP_DATA:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).ApproveTempData();
        break;
      case RequestProcessor.ADMIN_PAGE:
        try {
          boolean adm = false;
          if (request.getHeader('Authorization') != null) {
            adm = isUserAdmin(request.getHeader('Authorization'));
          }
          if (!adm) {
            response.sendRedirect(m_logonAddr);
          }
          else {
            ret = new AdminPage(request, response);
          }
        }
        catch (Exception e) {
          e.printStackTrace();
        }
        break;
      case RequestProcessor.LOAD_OLD_DATA_PAGE:
        try {
          boolean adm = false;
          if (request.getHeader('Authorization') != null) {
            adm = isUserAdmin(request.getHeader('Authorization'));
          }
          if (!adm) {
            response.sendRedirect(m_logonAddr);
          }
          else {
            ret = new LoadOldDataPage(request, response);
          }
        }
        catch (Exception e) {
          e.printStackTrace();
        }
        break;
      case RequestProcessor.LOAD_OLD_DATA:
        ret = new MainInvoker(request,response,m_rp.getParams(),false).LoadOldData();
        break;
      case RequestProcessor.DELETE_STORAGES_PAGE:
        try {
          boolean adm = false;
          if (request.getHeader('Authorization') != null) {
            adm = isUserAdmin(request.getHeader('Authorization'));
          }
          if (!adm) {
            response.sendRedirect(m_logonAddr);
          }
          else {
            ret = new DeleteStoragesPage(request, response);
          }
        }
        catch (Exception e) {
          e.printStackTrace();
        }
        break;
      case RequestProcessor.DELETE_STORAGE:
        ret = new MainInvoker(request, response,m_rp.getParams(),false).DeleteStorage();
        break;
      case RequestProcessor.DELETE_WORK_DATA:
        ret = new MainInvoker(request, response,m_rp.getParams(),

  public void GetPic() {
    try {
      String fileName = (String) m_params.get('file');
      fileName = new usf_sm.tools.EnvVars().getEnv('USF_SM_ROOT') + '/' +
          fileName;
      byte[] btData = Tools.GetByteFile(fileName);
      if (btData != null) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        baos.write(btData);
        baos.writeTo(m_response.getOutputStream());
      }
    } catch (Exception e) {
      System.out.println('MainInvoker::GetPic: ' + e.getMessage());
    }
  }
//--------------------