package edu.vt.marian.server;

import java.io.*;
import java.net.*;
import java.lang.*;
import java.util.*;

import edu.vt.marian.common.*;


/**
        class name:  class_dir_table
        class description: this class represents a table of class names and their
                corresponding directory names, this class is used by configuration 
                object to manage system class directories.
        uses the services of class(es): class_dir
        designer(s): Jianxin Zhao (jxzhao@csgrad.cs.vt.edu)
        implementator(s): Ning Chai (nchai@csgrad.cs.vt.edu)
        finished time: Nov 23, 1998
        known bugs: 
        JDK version: 1.1.5
        side effects:

*/

public class class_dir_table
{
        public final static int OK = 0;
        public final static int NULL_DIR_NAME_NEG= -1;
        public final static int NULL_CLASS_NAME = 1;
        public final static int NULL_DIR_NAME   = 2;
        public final static int CLASS_ALREADY_EXISTS    = 3;
        public final static int CLASS_DOESNT_EXIST = 4;
        
        private Vector class_dirs; //Used to hold the dir included in dir table

        /** this is just used for debugging
        */
        Debug debug;

        /**
                method description: this constructor will create a class dir table
                        object, the table is empty upon creation
                uses the services of class(es):
                input parameter(s): 
                        debug -- used for debugging
                output parameter(s): none
                return value: none
                synchronization:none
        */      
        public class_dir_table(Debug debug)
        {
                this.debug = debug;
                class_dirs = new Vector();
        }


        /**
                method description: this method will add the specified class name
                        and directory name pair to the table
                uses the services of class(es): none
                input parameter(s): 
                        class_name -- this is the name of a class, class name must be
                                uniq in the table (currently we don't allow one class has 
                                more than one directories)
                        dir_name -- this is the directory name corresponds to the class
                                name
                output parameter(s): none
                return value: 
                        0 -- the class name and directory name pair has been added into 
                                the table correctly
                        1 -- the class name is null
                        2 -- the directory name is null
                        3 -- duplicated class name identified
                synchronization:synchronized
        */      
        public synchronized int add(String class_name, String dir_name)
        {
                        int i;

                class_dir class_dir_obj = null;
                
                if ((class_name == null) || class_name.equals(""))
                {
                        debug.dumpTrace("Class: class_dir_table Method:add Class name is null or empty.");
                        return NULL_CLASS_NAME;
                }

                if ((dir_name == null)||dir_name.equals(""))
                {
                        debug.dumpTrace("Class: class_dir_table Method:add Dir name is null or empty.");
                        return NULL_DIR_NAME;
                }
        
                for (i = 0; i < class_dirs.size(); i++)
                {
                        class_dir_obj = (class_dir)(class_dirs.elementAt(i));
                        if (class_dir_obj.get_class_name().equals(class_name))
                        {
                                debug.dumpTrace("Class: class_dir_table Method:add Class already exists.\n");
                                return CLASS_ALREADY_EXISTS;
                        }
                }
                        
                //Insert class_dir into class_dirs
                class_dir_obj = new class_dir(class_name,dir_name,debug);
                class_dirs.addElement(class_dir_obj);

                return OK;

        }


        /**
                method description: this method will return the directory name 
                        corresponds to the specified class name in the table
                uses the services of class(es): none
                input parameter(s):
                        class_name -- this will be used to search the table
                output parameter(s): none
                return value: 
                        null -- class name is null or didn't find an entry in the table
                                with the same class name
                synchronization:synchronized
        */      
        public synchronized String get_dir_name(String class_name)
        {
                int i;
                class_dir class_dir_obj =null;

                if ((class_name == null)||class_name.equals(""))
                {
                        debug.dumpTrace("Class: class_dir_table Method:get_dir_name Class name is null or empty.");
                        return null;
                }

                for (i = 0; i < class_dirs.size(); i++)
                {
                        class_dir_obj = (class_dir)(class_dirs.elementAt(i));
                        if (class_dir_obj.get_class_name().equals(class_name))
                        {
                                return class_dir_obj.get_dir_name();
                        }
                }

                debug.dumpTrace("Class: class_dir_table Method: get_dir_name Can't find a dir with name'"
								+ class_name + "'.");
                return null;
        }


        /**
                method description: this method will delete the entry in the table 
                        with the specified class name
                uses the services of class(es):  
                input parameter(s): 
                        class_name -- the entry with the same class name will be deleted
                                from teh table
                output parameter(s): none
                return value: 
                        0 -- the entry has been deleted correctly
                        1 -- class name is null
                        4 -- there is no entry in the table with the specified class name
                synchronization:synchronized
        */      
        public synchronized int delete_by_class(String class_name)
        {
                int i;

                class_dir class_dir_obj = null;

                if ((class_name == null)||class_name.equals(""))
                {
                        debug.dumpTrace("Class:class_dir_name Method:delete_by_class Class name is null or empty.");
                        return NULL_CLASS_NAME;
                }

                for (i=0; i<class_dirs.size(); i++)
                {
                        class_dir_obj = (class_dir)(class_dirs.elementAt(i));
                        if (class_dir_obj.get_class_name().equals(class_name))
                        {
                                class_dirs.removeElementAt(i);
                                return OK;
                        }
                }

                debug.dumpTrace("Class:class_dir_table Method:delete_by_class Can't find dir with class name.");
                return CLASS_DOESNT_EXIST;
        }


        /**
                method description: this method will delete those entries in the table
                        whose directory name is the same as the specified value or is a 
                        subdirectory of the specified directory name
                uses the services of class(es):  
                input parameter(s): 
                        dir_name -- this will be used to search the table
                output parameter(s): none
                return value: 
                        non negative integer -- the number of entries deleted
                        -1 -- the directory name is null
                synchronization:synchronized
        */      
        public synchronized int delete_by_dir(String dir_name)
        {
                int i;
                class_dir class_dir_obj = null;

                int number_deleted = 0;

                if ((dir_name == null) || dir_name.equals(""))
                {
                        debug.dumpTrace("Class:class_dir_name Method:delete_by_dir Dir name is null or empty.");
                        return NULL_DIR_NAME_NEG;
                }

                for (i = class_dirs.size() - 1; i >= 0; i--)
                {
                        class_dir_obj = (class_dir)(class_dirs.elementAt(i)); 
                        if (class_dir_obj.get_dir_name().startsWith(dir_name))
                        {
                                class_dirs.removeElementAt(i);
                                number_deleted++;
                        }
                }

                return number_deleted;
}


        /**
                method description: this method will return the class name(s) whose
                        corresponding directory name is the same as the specified value
                        in the table
                uses the services of class(es):
                input parameter(s): 
                        dir_name -- this will be used to search the table
                output parameter(s): none
                return value: 
                        null -- the directory name is null
                        a vector -- contains all the class names match the directory name
                                in the table
                synchronization:none
        */      
        public Vector get_class_names(String dir_name)
        {
                int i;
                class_dir class_dir_obj = null;
                
                if ((dir_name == null) || dir_name.equals(""))
                {
                        debug.dumpTrace("Class:class_dir_name Method:get_class_name Dir name is null or empty.");
                        return null;
                }

                Vector class_names = new Vector();

                for (i=0; i<class_dirs.size(); i++)
                {
                        class_dir_obj = (class_dir)(class_dirs.elementAt(i));
                        if (class_dir_obj.get_dir_name().startsWith(dir_name))
                        {
                                class_names.addElement(class_dir_obj.get_class_name());
                        }
                }       
                return class_names;
        }
}