/* OS/2 Developer Magazine, Issue : Spring 93, page : 94-102 */
/* Article title : Method Resolution in SOM                  */
/* Authors : Roger Sessions and Nurcan Coskun                */

/* student.csc file: */
include <somobj.sc>

class:
  Student;

parent:
  SOMObject;

data:
  char  idÕ16þ;      /* student id */
  char  nameÕ32þ;    /* student name */

methods:
  override  somInit;

  void  setUpStudent(char *id, char *name), name lookup;
  -- sets up a new student.

  void  resetStudentId(char *id);
  -- resets student id.

  void  resetStudentName(char *name);
  -- resets student name.

  void  printStudentInfo();
  -- prints the student information.

  char  *getStudentType();
  -- returns the student type.

  char  *getStudentId();
  -- returns the student id.

--------------------------------------------------------------------------
/* student.c file: */

#define Student_Class_Source
#define SOM_NoTest
#include "student.ih"

SOM_Scope void   SOMLINK somInit(Student *somSelf)
{
    StudentData *somThis = StudentGetData(somSelf);
    parent_somInit(somSelf);
    _idÕ0þ = _nameÕ0þ = '\0';
}

SOM_Scope void   SOMLINK setUpStudent(Student *somSelf,
		char *id, char *name)
{
    StudentData *somThis = StudentGetData(somSelf);
    strcpy(_id, id);
    strcpy(_name, name);
}

SOM_Scope void   SOMLINK printStudentInfo(Student *somSelf)
{
    StudentData *somThis = StudentGetData(somSelf);
    printf("\n    Id         : %s \n", _id);
    printf("    Name       : %s \n", _name);
    printf("    Type       : %s \n", _getStudentType(somSelf));
}

SOM_Scope char *  SOMLINK getStudentType(Student *somSelf)
{
    StudentData *somThis = StudentGetData(somSelf);
    static char *type = "student";
    return (type);
}

SOM_Scope char *  SOMLINK getStudentId(Student *somSelf)
{
    StudentData *somThis = StudentGetData(somSelf);
    return (_id);
}

SOM_Scope void   SOMLINK resetStudentId(Student *somSelf,
		char *id)
{
    StudentData *somThis = StudentGetData(somSelf);
    StudentMethodDebug("Student","resetStudentId");
    strcpy(_id, id);
}

SOM_Scope void   SOMLINK resetStudentName(Student *somSelf,
		char *name)
{
    StudentData *somThis = StudentGetData(somSelf);
    StudentMethodDebug("Student","resetStudentName");
    strcpy(_name, name);
}
--------------------------------------------------------------------------
/* stdinter.c file: */
/* Student class interpreter code */

#include "student.h"
#include <stdio.h>
#define MAX_LENGTH 80

static void getLine(s, msg) /* get line into s */
char sÕþ;
char *msg;
{
  int i,c;
  printf(msg);
  for (i=0; i<(MAX_LENGTH-1) && (c=getchar()) != EOF && c!= '\n'; ++i)
    sÕiþ = c;
  sÕiþ = '\0';
}

main()
{
   int i, argNo;
   char *str, *arg;
   char *argList = NULL;
   char lineÕMAX_LENGTHþ;
   char methodÕMAX_LENGTHþ;
   char msgÕMAX_LENGTHþ;
   Student *student = StudentNew();

   /* display the menu options and read the operation */
     getLine(line, "\n> Menu Options are : 'm(message)' , 'q(quit)'\n$");
     while(lineÕ0þ == 'm'){
       /* query the message name */
         getLine(method, "> Enter method name:\n$");
       /* query the number of arguments */
         getLine(line, "> Enter the number of arguments:\n$");
         argNo = atoi(line);
       /* query the arguments */
         argList = (char *) malloc((sizeof (char *)) * argNo);
         for(i=0; i < argNo; ++i){
           sprintf(msg, "> Enter the argumentÕ%dþ:\n$", i);
           arg = (char *) malloc(MAX_LENGTH);
           getLine(arg, msg);
           *(char **)(argList + (i * sizeof(char *))) = arg;
         }
       /* query the return type */
         getLine(line, "> Enter the return type:\n$");
       /* send the message to student object */
         if(lineÕ0þ == 's'){
           str = (char *) SOMObject_somDispatchA(student,
                          somIdFromString(method), "", argList);
           printf("==> Return string from <%s> method is : <%s>.\n",
                                                        method, str);
         }
         else{
           SOMObject_somDispatchV(student, somIdFromString(method),
                                                      "", argList);
         }
       /* free the argList */
         for(i=0; i < argNo; ++i){
           arg = *(char **)(argList + (i * sizeof(char *)));
           free(arg);
         }
         free(argList);
         argList = NULL;
       /* query the next operation */
         getLine(line, "\n> Menu Options are : 'm(message)' , 'q(quit)'\n$");
   }
   _somFree(student);
}
--------------------------------------------------------------------------
/* main.c file: */
/* Demonstration of name lookup resolution */

#include "student.h"

typedef void (*methodType1) (SOMObject *, char *, char *);
typedef char * (*methodType2) (SOMObject *);

/* The following functions can be used to invoke methods
   with a fixed signature */

sendMessage1(char *method, SOMObject *target, char *str1, char *str2)
{
    somMethodProc *methodPtr;
    _somFindMethod(_somGetClass(target), somIdFromString(method),
                       &methodPtr);
    ((methodType1)methodPtr)(target,str1, str2);
}

char *sendMessage2(char *method, SOMObject *target)
{
    somMethodProc *methodPtr;
    _somFindMethod(_somGetClass(target), somIdFromString(method),
                       &methodPtr);
    return(((methodType2)methodPtr)(target));
}

main()
{
   Student *student1 = StudentNew();
   Student *student2 = StudentNew();
   char *id, *type;

   /* Offset resolution */
   _setUpStudent(student1, "599600", "David Brown");
   _printStudentInfo(student1);

   /* Name lookup resolution */
   sendMessage1("setUpStudent", student2, "120045", "Janet Smith");
   _printStudentInfo(student2);

   id = sendMessage2("getStudentId", student2);
   printf("Student Id = %s \n", id);

   type = sendMessage2("getStudentType", student2);
   printf("Student Type = %s \n", type);
}
--------------------------------------------------------------------------