9. The Ajanta Debugger

Overview of Debug statements and Debug file

1. Format of Debug statement:

        Debug("server.AgentServer.run", " run method being executed");

Debug statements takes two string parameters:
          -  first parameters is the name of the flag
          -  second parameter is the message to be printed
If the flag is set at the runtime then it will print the given message on standard
output . To include Debug statements in your files import ajanta.util.Debug  in
your java files.

2. Naming convention for flags:

Flags names are hierarchical in nature.
               PackageName.FileName.FunctionName
               i.e. server.AgentServer.run

3. Debug file and its conventions

Each user maintains a file named .ajanta/servers/Debug which conatins all the flags name which has to be enabled.  The flag entries in the files are also in hierarchical order. A sample Debug file is shown below

*********************************************************
Package = server
Class = AgentServer
#-------------------------------------------------------
#method names for this class
#-------------------------------------------------------

#AgentServer
getAgentCurrentServer
recall
retract
terminate
report
deleteDDEntry

#Class = AgentEnv
launch
registerResource
waitForResource
getResource
mapURNtoURL
createRMIProxy

#------------------------------------------------------------
#Package = agent
#Class = Agent
Agent
arrive
agentExit
start
colocate
#------------------------------------------------------------

The order of flag entries in the files are
  Packege Name
         Package = Server
  Class  Name ( or file name )
         Class = AgentServer
   Names of all the functions which has Debug Statements
           getAgentCurrentServer
              recall

Some of the flags that are enabled in the above Debug files are
             server.AgentServer.getAgentCurrentServer
             server.AgentServer.recall
             server.AgentServer.retract

'# ' is used to disable any flag .
If  it is used before function name then all the Debug statements in that function are disabled.
If it is used before  "Class = ClassName"   then all the Debug statements in that file are
disabled.
If it is used before  "Package = PackageName"   then all the Debug statements in that package
are disabled.

How to use the debugger?

Step 1:
To use the debugger first of all comment out all those flags that you do not need  by using '#' and
enter all the flags that you want to be enabled in the Debug file if they are not present. If they are
commented out by "#" then just remove them. You may have to remove "#" from Class and
Package statements appropriately.
 

 Step 2:
 Execute following commands
  1.  cd  .ajanta/servers
  2.   java ajanta.util.Debug

  It will print out all the flags that are being enabled.

Step 3:
    Enter 4 to exit and store all the enabled fllags in DebugHashTable file which will be used by
    all  the classes.
 

Currently option 1,2 and 3 need to be refined and for the time being just ignore them. Their working
should be of the nature described below.

 The process started in Step 2 above will allow one to set and reset a flage at run time. Option 1 and 2
 ask a user to enter Package name, File or Class Name and Function name and it enables or disables
  corresponding flag.
 

The following two files are needed to run the ajanta debugger:
1. .ajanta/servers/Debug
2. .ajanta/servers/DebugHashTable

Please comment out the module (class) or method to disable debug messages for that m
odule or method.

Run
> java ajanta.util.Debug

An example session
***************************************************************
tahmed@newton (~/.ajanta/servers) % java ajanta.util.Debug
WriteHashtable:Wrote the hash table950638319000
Command 1. set  2. reset  3. readflag 4. exit  :

***************************************************************

This can be used interactively to set or unset debug modules.

NOTE: Know bugs:
The module need to have the above two files