This is basic design document for the Plug-in

Introduction

Any Chat Client which has support for plug-ins can be provided this language translation feature. Lingua-Franca plug-in would be basically a shared Object file or a dll file with core functions being

• User Interface for preference setting

void lf_ui()

• Translate Outgoing messages

char *lf_translate_outgoing_mesg(char *mesg,char *buddy)

• Translate Incoming messages

char *lf_translate_incoming_mesg(char *mesg,char *buddy)

There are four basic modules in the plug-in

• Chat client Specific Module
• Plug-in Specific Modules
• User Interface Module
• Core Translation Module
• XML Helper Module

Chat Client Specific Module

Skeleton of the chat client specific code would be

• Initialize the plug-in
• Load the plug-in into chat client
• User to configure the preferences
• Wait for the signal "message-typed"
• Call translate_outgoing_message method when event occurs
• Send the translated message to the concerned buddy
• Wait for the signal "message-received"
• Call translate_incoming_message method when event occurs
• Send the translated message back to chat client
• Unload the plug-in gracefully when the chat client process is shutdown

Note The above design is highly specific to pidgin , more generic design will be made once we are ready to develop for other chat clients

Plug-in Specific Modules

Plug-in has three modules

• User Interface Module
• Initialize the Preferences window.
• Core Translation Module
• Translate Outgoing Messages
• Translate Incoming Messages
• XML Helper Module Provides Helper Methods
• To save user preferences
• To read the translation service config files

User Interface

1. Initialization of the User Interface the below are required
• List of buddies available

This can be got from the layer above , i.e from Chat Client API.

• List of available Languages

This can be got from the XML Helper

• List of available Translation Services

This can be got from the XML Helper

• XML File Location.

The directory path to preferences XML

2. Preferences Window Layout and Components
1. General Tab
• Incoming Language Preference
• An Incoming Lang Preference Label
• A Combo Box containing list of available languages
• Outgoing Language Preference
• An Outgoing Lang Preference Label
• A Combo Box containing list of available languages
2. Buddy Config Tab
• A table having three columns
• Buddy Name
• List of available languages
• Enable/ Disable button
3. Miscellaneous Tab
• Translation Service
• Translation service label
• Combo Box containing list of available Servers
• View Translation
• View Translation label
• Enable / Disable Button
• Time Out
• Time out label
• Spin button for counter
4. Ok , Apply , Cancel Buttons
• A Panel containing Ok , Apply ,Cancel Buttons common to all the three tabs
3. Call back Methods and Saving Preferences
• Call back methods for all the above widgets should be provided
• Changes in the any of the preferences to be updated in the memory and written to an XML file only when "Apply" or "Ok" are clicked
4. A DTD of the XML file is provided in the XML Helper Module Section

Core Translation Module

1. Translate Outgoing Messages

              char *lf_translate_outgoing_mesg(char *mesg,char *buddy)
              {
                 char *to_lang ;
                 char *from_lang;
                 char *translated_mesg;
                /* determine outgoing language preference for this buddy*/
                     to = get_lang_pref(buddy) 

                /* determine the language of the "mesg" */
                     from = determine_lang(mesg)

                /* call the core translate method */
                     translated_mesg = translate (mesg,from ,to);             
               }

2. Translate Incoming Messages

              char *lf_translate_incoming_mesg(char *mesg,char *buddy)
              {
                 char *to_lang ;
                 char *from_lang;
                 char *translated_mesg;
                /* determine incoming language preference */
                     to = get_incoming_lang_pref() 

                /* determine the language of the "mesg" */
                     from = determine_lang(mesg)

                /* call the core translate method */
                     translated_mesg = translate (mesg,from ,to);             
               }

3. Other Methods
1. Translate method needs the following inputs

char *translate(char *mesg,char *to, char *from)

2. Determine Language Method

                       char *determine_lang(char *mesg)
                       {
                          List avail_translations;
                          char *translated_mesg;
                           while ( list->next != NULL)
                            {
                              avail = list->avail;
                              translated_mesg = translate(mesg,avail->from,avail->to);
                              if (strcmp(mesg,translated_mesg) !=0)
                               {
                                  printf("Translation Available");
                                  return avail->from;
                               }
                             }
                           return "NA";
                         }

XML Helper Module

This module basically does the required XML processing , it has two sub modules

• XML - User Preferences

The User Preferences will be saved in an XML file , the DTD of this file will be soon given

• XML - Translate

The translation service specific details are provided in an XML File , the DTD will be soon posted .