* landed code for viewing topics in a conference, and for adding a topic

(first workout of HTML Checker code)
* modified the dictionary implementation to use a trie system rather than
  a set of HashSets, and also started using a new, much smaller dictionary
* general bugfixes and cleanup on other items as needed

src/com/silverwrist/venice/servlets/ConfDisplay.java

@@ -213,6 +213,8 @@ public class ConfDisplay extends VeniceServlet
       { // all commands require a SIG parameter
 	sig = getSIGParameter(request,user);
 	changeMenuSIG(request,sig);
+	if (logger.isDebugEnabled())
+	  logger.debug("found SIG #" + String.valueOf(sig.getSIGID()));
 
       } // end try
       catch (DataException de)
@@ -222,11 +224,13 @@ public class ConfDisplay extends VeniceServlet
 
       } // end catch
 
-      if (content!=null)
+      if (content==null)
       { // we got the SIG parameter OK
 	try
 	{ // all commands require a conference parameter
 	  conf = getConferenceParameter(request,sig);
+	  if (logger.isDebugEnabled())
+	    logger.debug("found conf #" + String.valueOf(conf.getConfID()));
 	  
 	} // end try
 	catch (DataException de)
@@ -238,11 +242,19 @@ public class ConfDisplay extends VeniceServlet
 
       } // end if
 
-      if (content!=null)
+      if (content==null)
       { // we got the conference parameter OK
 	try
 	{ // there's an optional topic parameter
 	  topic = getTopicParameter(request,conf);
+	  if (logger.isDebugEnabled())
+	  { // do a little debugging output
+	    if (topic!=null)
+	      logger.debug("found topic #" + String.valueOf(topic.getTopicID()));
+	    else
+	      logger.debug("no topic specified");
+
+	  } // end if
 
 	} // end try
 	catch (DataException de)
@@ -268,26 +280,30 @@ public class ConfDisplay extends VeniceServlet
 
     } // end catch
 
-    if (content!=null)
+    if (content==null)
     { // OK, let's handle the display now
       if (topic!=null)
       { // we're handling messages within a single topic
+	if (logger.isDebugEnabled())
+	  logger.debug("MODE: display messages in topic");
+
 	// TODO: handle this somehow
+
       } // end if
       else
       { // we're displaying the conference's topic list
+	if (logger.isDebugEnabled())
+	  logger.debug("MODE: display topics in conference");
+
 	TopicSortHolder opts = TopicSortHolder.retrieve(request.getSession(true));
 	try
 	{ // get any changes to view or sort options
 	  getViewSortDefaults(request,conf.getConfID(),opts);
 
-	  // get the topic list in the desired order!
-	  List topic_list = conf.getTopicList(opts.getViewOption(conf.getConfID()),
-					      opts.getSortOption(conf.getConfID()));
-
-	  // TODO: create the "next topic" list to use for "read next"
-
-	  // TODO: create the page view
+	  // create the topic list
+	  content = new TopicListing(request,sig,conf,opts.getViewOption(conf.getConfID()),
+				     opts.getSortOption(conf.getConfID()));
+	  page_title = "Topics in " + conf.getName();
 
 	} // end try
 	catch (ValidationException ve)

src/com/silverwrist/venice/servlets/ConfOperations.java

@@ -7,7 +7,7 @@
  * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
  * language governing rights and limitations under the License.
  * 
- * The Original Code is the Venice Web Community System.
+ * The Original Code is the Venice Web Communities System.
  * 
  * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
  * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are
@@ -65,6 +65,32 @@ public class ConfOperations extends VeniceServlet
 
   } // end getSIGParameter
 
+  private static ConferenceContext getConferenceParameter(ServletRequest request, SIGContext sig)
+    throws ValidationException, DataException, AccessError
+  {
+    String str = request.getParameter("conf");
+    if (str==null)
+    { // no conference parameter - bail out now!
+      logger.error("Conference parameter not specified!");
+      throw new ValidationException("No conference specified.");
+
+    } // end if
+
+    try
+    { // turn the string into a ConfID, and thence to a ConferenceContext
+      int confid = Integer.parseInt(str);
+      return sig.getConferenceContext(confid);
+
+    } // end try
+    catch (NumberFormatException nfe)
+    { // error in Integer.parseInt
+      logger.error("Cannot convert conference parameter '" + str + "'!");
+      throw new ValidationException("Invalid conference parameter.");
+
+    } // end catch
+
+  } // end getConferenceParameter
+
   private CreateConferenceDialog makeCreateConferenceDialog() throws ServletException
   {
     final String desired_name = "CreateConferenceDialog";
@@ -82,6 +108,28 @@ public class ConfOperations extends VeniceServlet
 
   } // end makeCreateConferenceDialog
 
+  private static boolean validateNewTopic(ServletRequest request) throws ValidationException
+  {
+    boolean is_title_null, is_zp_null;
+
+    String foo = request.getParameter("title");
+    if (foo==null)
+      throw new ValidationException("Title parameter was not specified.");
+    is_title_null = (foo.length()==0);
+
+    foo = request.getParameter("pseud");
+    if (foo==null)
+      throw new ValidationException("Pseud parameter was not specified.");
+
+    foo = request.getParameter("pb");
+    if (foo==null)
+      throw new ValidationException("Body text was not specified.");
+    is_zp_null = (foo.length()==0);
+
+    return is_title_null || is_zp_null;
+      
+  } // end validateNewTopic
+
   /*--------------------------------------------------------------------------------
    * Overrides from class HttpServlet
    *--------------------------------------------------------------------------------
@@ -147,6 +195,42 @@ public class ConfOperations extends VeniceServlet
 	} // end else
 
       } // end if
+      else if (cmd.equals("T"))
+      { // "T" = "Create topic" (requires conference parameter)
+	try
+	{ // start by getting the conference parameter
+	  ConferenceContext conf = getConferenceParameter(request,sig);
+
+	  // create the New Topic form
+	  NewTopicForm ntf = new NewTopicForm(sig,conf);
+	  ntf.setupNewRequest();
+	  content = ntf;
+	  page_title = "Create New Topic";
+
+	} // end try
+	catch (ValidationException ve)
+	{ // we can't get the conference parameter
+	  page_title = "Error";
+	  content = new ErrorBox(null,ve.getMessage(),
+				 "sigprofile?sig=" + String.valueOf(sig.getSIGID()));
+
+	} // end catch
+	catch (AccessError ae)
+	{ // we have some sort of access problem
+	  page_title = "Access Error";
+	  content = new ErrorBox(page_title,ae.getMessage(),
+				 "sigprofile?sig=" + String.valueOf(sig.getSIGID()));
+
+	} // end catch
+	catch (DataException de)
+	{ // some sort of error in the database
+	  page_title = "Database Error";
+	  content = new ErrorBox(page_title,"Database error finding conference: " + de.getMessage(),
+				 "sigprofile?sig=" + String.valueOf(sig.getSIGID()));
+
+	} // end catch
+
+      } // end else
       else
       { // any unrecognized command jumps us to "conference list"
 	try
@@ -239,9 +323,9 @@ public class ConfOperations extends VeniceServlet
 	    { // attempt to create the conference!
 	      ConferenceContext conf = dlg.doDialog(sig);
 
-	      // success! go back to the conference list
-	      // TODO: want to jump to the conference's "topic list" page if possible
-	      rdat.redirectTo(location);
+	      // success! go to the conference's topic list
+	      rdat.redirectTo("confdisp?sig=" + String.valueOf(sig.getSIGID()) + "&conf="
+			      + String.valueOf(conf.getConfID()));
 	      return;
 
 	    } // end try
@@ -284,7 +368,136 @@ public class ConfOperations extends VeniceServlet
 
 	} // end else
 
-      } // end if
+      } // end if ("C" command)
+      else if (cmd.equals("T"))
+      { // "T" command = Create New Topic (requires conference parameter)
+	ConferenceContext conf = null;
+
+	try
+	{ // start by getting the conference parameter
+	  conf = getConferenceParameter(request,sig);
+
+	} // end try
+	catch (ValidationException ve)
+	{ // we can't get the conference parameter
+	  page_title = "Error";
+	  content = new ErrorBox(null,ve.getMessage(),location);
+
+	} // end catch
+	catch (AccessError ae)
+	{ // we have some sort of access problem
+	  page_title = "Access Error";
+	  content = new ErrorBox(page_title,ae.getMessage(),location);
+
+	} // end catch
+	catch (DataException de)
+	{ // some sort of error in the database
+	  page_title = "Database Error";
+	  content = new ErrorBox(page_title,"Database error finding conference: " + de.getMessage(),location);
+
+	} // end catch
+
+	if (content==null)
+	{ // determine what to do based on the button pressed
+	  String on_error = "confdisp?sig=" + String.valueOf(sig.getSIGID()) + "&conf="
+                          + String.valueOf(conf.getConfID());
+	  if (isImageButtonClicked(request,"cancel"))
+	  { // the user chickened out - go back to the conference display
+	    rdat.redirectTo(on_error);
+	    return;
+
+	  } // end if
+
+	  if (isImageButtonClicked(request,"preview"))
+	  { // generate a preview and redisplay the form
+	    NewTopicForm ntf = new NewTopicForm(sig,conf);
+
+	    try
+	    { // do a preview generation
+	      ntf.generatePreview(getVeniceEngine(),request);
+
+	      if (ntf.isNullRequest())
+	      { // no title or text specified - this is a "204 No Content" return
+		rdat.nullResponse();
+		return;
+
+	      } // end if
+
+	      content = ntf;
+	      page_title = "Preview New Topic";
+
+	    } // end try
+	    catch (ValidationException ve)
+	    { // something messed up in the preview generation
+	      page_title = "Error";
+	      content = new ErrorBox(null,ve.getMessage(),on_error);
+
+	    } // end catch
+
+	  } // end if ("preview" button clicked)
+	  else if (isImageButtonClicked(request,"post"))
+	  { // OK, let's do a post request!
+	    try
+	    { // first validate that we've got all the parameters
+	      if (validateNewTopic(request))
+	      { // this is a null request - send a null response
+		rdat.nullResponse();
+		return;
+
+	      } // end if
+
+	      // add the new topic!
+	      TopicContext topic = conf.addTopic(request.getParameter("title"),request.getParameter("pseud"),
+						 request.getParameter("pb"));
+
+	      final String yes = "Y";
+	      if (yes.equals(request.getParameter("attach")))
+	      { // we need to upload an attachment for this post
+		// TODO: jump somewhere to upload an attachment
+		rdat.redirectTo(on_error);
+		return;
+
+	      } // end if
+	      else
+	      { // the post is complete, we need only jump to the topic
+		// TODO: jump straight to the new topic
+		rdat.redirectTo(on_error);
+		return;
+
+	      } // end else
+
+	    } // end try
+	    catch (ValidationException ve)
+	    { // the validation of parameters failed
+	      page_title = "Error";
+	      content = new ErrorBox(null,ve.getMessage(),on_error);
+
+	    } // end catch
+	    catch (DataException de)
+	    { // display a database error
+	      page_title = "Database Error";
+	      content = new ErrorBox(page_title,"Database error adding topic: " + de.getMessage(),on_error);
+
+	    } // end catch
+	    catch (AccessError ae)
+	    { // some sort of access problem
+	      page_title = "Access Error";
+	      content = new ErrorBox(page_title,ae.getMessage(),on_error);
+
+	    } // end catch
+
+	  } // end else if
+	  else
+	  { // we don't know what button was pressed
+	    page_title = "Internal Error";
+	    logger.error("no known button click on ConfOperations.doPost, cmd=T");
+	    content = new ErrorBox(page_title,"Unknown command button pressed",on_error);
+
+	  } // end else
+
+	} // end if (we got the conference parameter OK)
+
+      } // end else if ("T" command)
       else
       { // unrecognized command!
 	page_title = "Internal Error";

src/com/silverwrist/venice/servlets/Variables.java

@@ -48,6 +48,7 @@ public class Variables
   public static final String LOGIN_COOKIE = "VeniceLogin";
 
   private static Category logger = Category.getInstance(Variables.class.getName());
+  private static Integer engine_gate = new Integer(0);
 
   /*--------------------------------------------------------------------------------
    * External static operations
@@ -56,32 +57,36 @@ public class Variables
 
   public static VeniceEngine getVeniceEngine(ServletContext ctxt) throws ServletException
   {
-    Object foo = ctxt.getAttribute(ENGINE_ATTRIBUTE);
-    if (foo!=null)
-      return (VeniceEngine)foo;
+    synchronized(engine_gate)
+    { // we must synchronize efforts to access the engine
+      Object foo = ctxt.getAttribute(ENGINE_ATTRIBUTE);
+      if (foo!=null)
+	return (VeniceEngine)foo;
 
-    String cfgfile = ctxt.getInitParameter(ENGINE_INIT_PARAM);  // get the config file name
-    logger.info("Initializing Venice engine using config file: " + cfgfile);
+      String cfgfile = ctxt.getInitParameter(ENGINE_INIT_PARAM);  // get the config file name
+      logger.info("Initializing Venice engine using config file: " + cfgfile);
 
-    try
-    { // extract the configuration file name and create the engine
-      VeniceEngine engine = Startup.createEngine(cfgfile);
-      ctxt.setAttribute(ENGINE_ATTRIBUTE,engine);
-      return engine;
+      try
+      { // extract the configuration file name and create the engine
+	VeniceEngine engine = Startup.createEngine(cfgfile);
+	ctxt.setAttribute(ENGINE_ATTRIBUTE,engine);
+	return engine;
 
-    } // end try
-    catch (ConfigException e)
-    { // configuration failed!  post an error message
-      logger.fatal("Engine configuration failed: " + e.getMessage(),e);
-      throw new ServletException("Venice engine configuration failed: " + e.getMessage(),e);
+      } // end try
+      catch (ConfigException e)
+      { // configuration failed!  post an error message
+	logger.fatal("Engine configuration failed: " + e.getMessage(),e);
+	throw new ServletException("Venice engine configuration failed: " + e.getMessage(),e);
 
-    } // end catch
-    catch (DataException e2)
-    { // configuration failed!  post an error message
-      logger.fatal("Engine data load failed: " + e2.getMessage(),e2);
-      throw new ServletException("Venice engine data load failed: " + e2.getMessage(),e2);
+      } // end catch
+      catch (DataException e2)
+      { // configuration failed!  post an error message
+	logger.fatal("Engine data load failed: " + e2.getMessage(),e2);
+	throw new ServletException("Venice engine data load failed: " + e2.getMessage(),e2);
 
-    } // end catch
+      } // end catch
+
+    } // end synchronized block
 
   } // end getVeniceEngine
 

src/com/silverwrist/venice/servlets/format/ConferenceListing.java

@@ -7,7 +7,7 @@
  * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
  * language governing rights and limitations under the License.
  * 
- * The Original Code is the Venice Web Community System.
+ * The Original Code is the Venice Web Communities System.
  * 
  * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
  * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are

src/com/silverwrist/venice/servlets/format/NewTopicForm.java

@@ -0,0 +1,224 @@
+/*
+ * The contents of this file are subject to the Mozilla Public License Version 1.1
+ * (the "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at <http://www.mozilla.org/MPL/>.
+ * 
+ * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
+ * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
+ * language governing rights and limitations under the License.
+ * 
+ * The Original Code is the Venice Web Communities System.
+ * 
+ * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
+ * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are
+ * Copyright (C) 2001 Eric J. Bowersox/Silverwrist Design Studios.  All Rights Reserved.
+ * 
+ * Contributor(s): 
+ */
+package com.silverwrist.venice.servlets.format;
+
+import java.util.*;
+import javax.servlet.*;
+import com.silverwrist.venice.ValidationException;
+import com.silverwrist.venice.htmlcheck.*;
+import com.silverwrist.venice.core.*;
+
+public class NewTopicForm implements JSPRender
+{
+  /*--------------------------------------------------------------------------------
+   * Static data members
+   *--------------------------------------------------------------------------------
+   */
+
+  // Attribute name for request attribute
+  protected static final String ATTR_NAME = "com.silverwrist.venice.content.NewTopicForm";
+
+  /*--------------------------------------------------------------------------------
+   * Attributes
+   *--------------------------------------------------------------------------------
+   */
+
+  private SIGContext sig;               // the SIG we're in
+  private ConferenceContext conf;       // the conference being created in
+  private String topic_name;            // the initial topic name
+  private String pseud;                 // the pseud to display
+  private boolean attach;               // is there an attachment?
+  private String post_box;              // stuff from the post box
+  private String preview = null;        // the preview & spellchuck data
+  private int num_errors = 0;           // the number of spelling errors we get
+
+  /*--------------------------------------------------------------------------------
+   * Constructor
+   *--------------------------------------------------------------------------------
+   */
+
+  public NewTopicForm(SIGContext sig, ConferenceContext conf)
+  {
+    this.sig = sig;
+    this.conf = conf;
+
+  } // end constrcutor
+
+  /*--------------------------------------------------------------------------------
+   * External static functions
+   *--------------------------------------------------------------------------------
+   */
+
+  public static NewTopicForm retrieve(ServletRequest request)
+  {
+    return (NewTopicForm)(request.getAttribute(ATTR_NAME));
+
+  } // end retrieve
+
+  /*--------------------------------------------------------------------------------
+   * Implementations from interface JSPRender
+   *--------------------------------------------------------------------------------
+   */
+
+  public void store(ServletRequest request)
+  {
+    request.setAttribute(ATTR_NAME,this);
+
+  } // end store
+
+  public String getTargetJSPName()
+  {
+    return "newtopic.jsp";
+
+  } // end getTargetJSPName
+
+  /*--------------------------------------------------------------------------------
+   * External operations
+   *--------------------------------------------------------------------------------
+   */
+
+  public void setupNewRequest()
+  {
+    topic_name = "";
+    pseud = conf.getDefaultPseud();
+    attach = false;
+    post_box = "";
+
+  } // end setupNewRequest
+
+  public void generatePreview(VeniceEngine engine, ServletRequest request) throws ValidationException
+  {
+    HTMLChecker check;
+
+    try
+    { // run the data through the HTML Checker
+      check = engine.getEscapingChecker();
+
+      // sanitize the "title" parameter
+      String foo = request.getParameter("title");
+      if (foo==null)
+	throw new ValidationException("Title parameter was not specified.");
+      check.append(foo);
+      check.finish();
+      topic_name = check.getValue();
+      check.reset();
+
+      // sanitize the "pseud" parameter
+      foo = request.getParameter("pseud");
+      if (foo==null)
+	throw new ValidationException("Pseud parameter was not specified.");
+      check.append(foo);
+      check.finish();
+      pseud = check.getValue();
+      check.reset();
+
+      // sanitize the body text itself
+      foo = request.getParameter("pb");
+      if (foo==null)
+	throw new ValidationException("Body text was not specified.");
+      check.append(foo);
+      check.finish();
+      post_box = check.getValue();
+
+      // generate the body text preview
+      check = engine.getPreviewChecker();
+      check.append(foo);
+      check.finish();
+      preview = check.getValue();
+      num_errors = check.getCounter("spelling");
+
+    } // end try
+    catch (HTMLCheckerException e)
+    { // make sure we catch the HTML Checker exceptions
+      throw new InternalStateError("spurious HTMLCheckerException in generatePreview",e);
+
+    } // end catch
+
+    // set the "attach" flag to save the checkbox state
+    final String yes = "Y";
+    attach = yes.equals(request.getParameter("attach"));
+
+  } // end generatePreview
+
+  public int getSIGID()
+  {
+    return sig.getSIGID();
+
+  } // end getSIGID
+
+  public int getConfID()
+  {
+    return conf.getConfID();
+
+  } // end getConfID
+
+  public String getConfName()
+  {
+    return conf.getName();
+
+  } // end getConfName
+
+  public String getTopicName()
+  {
+    return topic_name;
+
+  } // end getTopicName
+
+  public String getPseud()
+  {
+    return pseud;
+
+  } // end getPseud
+
+  public boolean getAttachCheck()
+  {
+    return attach;
+
+  } // end getAttachCheck
+
+  public String getPostBoxData()
+  {
+    return post_box;
+
+  } // end getPostBoxData
+
+  public boolean isPreview()
+  {
+    return (preview!=null);
+
+  } // end isPreview
+
+  public String getPreviewData()
+  {
+    return preview;
+
+  } // end getPreviewData
+
+  public int getNumSpellingErrors()
+  {
+    return num_errors;
+
+  } // end getNumSpellingErrors
+
+  public boolean isNullRequest()
+  {
+    return ((topic_name.length()==0) || (post_box.length()==0));
+
+  } // end isNullRequest
+
+} // end class NewTopicForm

src/com/silverwrist/venice/servlets/format/RenderData.java

@@ -293,4 +293,10 @@ public class RenderData
 
   } // end getActivityString
 
+  public void nullResponse()
+  {
+    response.setStatus(response.SC_NO_CONTENT);
+
+  } // end nullResponse
+
 } // end class RenderData

src/com/silverwrist/venice/servlets/format/TopicListing.java

@@ -0,0 +1,163 @@
+/*
+ * The contents of this file are subject to the Mozilla Public License Version 1.1
+ * (the "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at <http://www.mozilla.org/MPL/>.
+ * 
+ * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
+ * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
+ * language governing rights and limitations under the License.
+ * 
+ * The Original Code is the Venice Web Communities System.
+ * 
+ * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
+ * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are
+ * Copyright (C) 2001 Eric J. Bowersox/Silverwrist Design Studios.  All Rights Reserved.
+ * 
+ * Contributor(s): 
+ */
+package com.silverwrist.venice.servlets.format;
+
+import java.util.*;
+import javax.servlet.*;
+import javax.servlet.http.*;
+import com.silverwrist.venice.core.*;
+
+public class TopicListing implements JSPRender
+{
+  /*--------------------------------------------------------------------------------
+   * Static data members
+   *--------------------------------------------------------------------------------
+   */
+
+  // Attribute name for request attribute
+  protected static final String ATTR_NAME = "com.silverwrist.venice.content.TopicListing";
+
+  /*--------------------------------------------------------------------------------
+   * Attributes
+   *--------------------------------------------------------------------------------
+   */
+
+  private SIGContext sig;               // the SIG we're in
+  private ConferenceContext conf;       // the conference being listed
+  private int view_opt;                 // the view option used
+  private int sort_opt;                 // the sort option used
+  private List topic_list;              // the topic list
+  private TopicVisitOrder visit_order;  // indicates order in which topics are visited
+
+  /*--------------------------------------------------------------------------------
+   * Constructor
+   *--------------------------------------------------------------------------------
+   */
+
+  public TopicListing(HttpServletRequest request, SIGContext sig, ConferenceContext conf, int view_opt,
+		      int sort_opt) throws DataException, AccessError
+  {
+    this.sig = sig;
+    this.conf = conf;
+    this.view_opt = view_opt;
+    this.sort_opt = sort_opt;
+    this.topic_list = conf.getTopicList(view_opt,sort_opt);
+    this.visit_order = TopicVisitOrder.initialize(request.getSession(true),conf.getConfID(),this.topic_list);
+
+  } // end constructor
+
+  /*--------------------------------------------------------------------------------
+   * External static functions
+   *--------------------------------------------------------------------------------
+   */
+
+  public static TopicListing retrieve(ServletRequest request)
+  {
+    return (TopicListing)(request.getAttribute(ATTR_NAME));
+
+  } // end retrieve
+
+  /*--------------------------------------------------------------------------------
+   * Implementations from interface JSPRender
+   *--------------------------------------------------------------------------------
+   */
+
+  public void store(ServletRequest request)
+  {
+    request.setAttribute(ATTR_NAME,this);
+
+  } // end store
+
+  public String getTargetJSPName()
+  {
+    return "topics.jsp";
+
+  } // end getTargetJSPName
+
+  /*--------------------------------------------------------------------------------
+   * External operations
+   *--------------------------------------------------------------------------------
+   */
+
+  public int getSIGID()
+  {
+    return sig.getSIGID();
+
+  } // end getSIGID
+
+  public int getConfID()
+  {
+    return conf.getConfID();
+
+  } // end getConfID
+
+  public String getConfName()
+  {
+    return conf.getName();
+
+  } // end getConfName
+
+  public boolean canDoReadNew()
+  {
+    return visit_order.isNext();
+
+  } // end canDoReadNew
+
+  public boolean canCreateTopic()
+  {
+    return conf.canCreateTopic();
+
+  } // end canCreateTopic
+
+  public boolean canAddToHotlist()
+  {
+    return false;  // TODO: fix this
+
+  } // end canAddToHotlist
+
+  public boolean anyTopics()
+  {
+    return (topic_list.size()>0);
+
+  } // end anyTopics
+
+  public int getViewOption()
+  {
+    return view_opt;
+
+  } // end getViewOption
+
+  public boolean isView(int value)
+  {
+    return (view_opt==value);
+
+  } // end isSort
+
+  public boolean isSort(int value)
+  {
+    return (sort_opt==value);
+
+  } // end isSort
+
+  public Iterator getTopicIterator()
+  {
+    return topic_list.iterator();
+
+  } // end getTopicIterator
+
+} // end class TopicListing

src/com/silverwrist/venice/servlets/format/TopicVisitOrder.java

@@ -0,0 +1,172 @@
+/*
+ * The contents of this file are subject to the Mozilla Public License Version 1.1
+ * (the "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at <http://www.mozilla.org/MPL/>.
+ * 
+ * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
+ * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
+ * language governing rights and limitations under the License.
+ * 
+ * The Original Code is the Venice Web Communities System.
+ * 
+ * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
+ * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are
+ * Copyright (C) 2001 Eric J. Bowersox/Silverwrist Design Studios.  All Rights Reserved.
+ * 
+ * Contributor(s): 
+ */
+package com.silverwrist.venice.servlets.format;
+
+import java.util.*;
+import javax.servlet.*;
+import javax.servlet.http.*;
+import com.silverwrist.venice.core.*;
+
+public class TopicVisitOrder
+{
+  /*--------------------------------------------------------------------------------
+   * Static data members
+   *--------------------------------------------------------------------------------
+   */
+
+  protected static final String ATTRIBUTE = "conf.display.topic.visitorder";
+
+  /*--------------------------------------------------------------------------------
+   * Attributes
+   *--------------------------------------------------------------------------------
+   */
+
+  private int confid;
+  private short[] topics;
+  private boolean[] unread;
+  private int ndx_next;
+
+  /*--------------------------------------------------------------------------------
+   * Constructor
+   *--------------------------------------------------------------------------------
+   */
+
+  protected TopicVisitOrder(int confid, List topiclist)
+  {
+    this.confid = confid;
+    this.topics = new short[topiclist.size()];
+    this.unread = new boolean[topiclist.size()];
+
+    ndx_next = -1;
+    for (int i=0; i<topiclist.size(); i++)
+    { // fill in topic numbers and unread states
+      TopicContext t = (TopicContext)(topiclist.get(i));
+      topics[i] = t.getTopicNumber();
+      unread[i] = (t.getUnreadMessages()>0);
+      if (unread[i] && (ndx_next<0))
+	ndx_next = i;
+
+    } // end for
+
+  } // end constructor
+
+  private int moveNext()
+  {
+    int i = ndx_next;
+    do
+    { // move forward to next "unread" topic
+      if (unread[i])
+	break;
+      if (++i==unread.length)
+	i = 0;
+
+    } while (i!=ndx_next);  // end do
+
+    return i;
+
+  } // end moveNext
+
+  /*--------------------------------------------------------------------------------
+   * External static functions
+   *--------------------------------------------------------------------------------
+   */
+
+  public static TopicVisitOrder initialize(HttpSession session, int confid, List topic_list)
+  {
+    TopicVisitOrder tvo = new TopicVisitOrder(confid,topic_list);
+    session.setAttribute(ATTRIBUTE,tvo);
+    return tvo;
+
+  } // end initialize
+
+  public static TopicVisitOrder retrieve(HttpSession session, int confid)
+  {
+    TopicVisitOrder tvo = (TopicVisitOrder)(session.getAttribute(ATTRIBUTE));
+    if (tvo!=null)
+    { // make sure the conference is OK
+      if (tvo.confid!=confid)
+      { // wrong conference - remove this
+	session.removeAttribute(ATTRIBUTE);
+	tvo = null;
+
+      } // end if
+
+    } // end if
+
+    return tvo;
+
+  } // end retrieve
+  
+  /*--------------------------------------------------------------------------------
+   * External operations
+   *--------------------------------------------------------------------------------
+   */
+
+  public short getNext()
+  {
+    if (ndx_next<0)
+      return -1;
+    else if (unread[ndx_next])
+      return topics[ndx_next];
+    else
+      return -1;
+
+  } // end getNext
+
+  public boolean isNext()
+  {
+    if (ndx_next>=0)
+      return unread[ndx_next];
+    else
+      return false;
+
+  } // end isNext
+
+  public void visit(short topnum)
+  {
+    if (ndx_next<0)
+      return;
+
+    if (topics[ndx_next]!=topnum)
+    { // go searching for the matching topic number
+      for (int i=0; i<topics.length; i++)
+      { // simple linear search - can't be tricky because the topic numbers might be
+	// in any order
+	if (topnum==topics[i])
+	{ // plant ourselves right there
+	  unread[i] = false;
+	  ndx_next = i;
+	  break;
+
+	} // end if
+
+      } // end for
+
+    } // end if
+    else
+      unread[ndx_next] = false;
+
+    // move the "next" pointer
+    ndx_next = moveNext();
+
+  } // end visit
+
+} // end class TopicVisitOrder
+
+
+