Command Method Pattern

Definisi
Command merupakan salah satu bagian dari Behavioral Design Pattern, dimana ia mengumpulkan atau melakukan enkapsulasi sejumlah command kedalam sebuah object sehingga bisa melakukan pengurutan kepada klien yang meminta command terhadap object tersebut.

Struktur
Secara umum, struktur Command Pattern adalah sebagai berikut,

• Client - Object yang meminta dilakukannya operasi. Juga membentuk ConcreteCommand dan menyiapkan Receiver
• Command - Interface untuk mengeksekusi operasi
• Receiver - Object yang siap menerima operasi
• Invoker - Object yang menerima permintaan dari client
• ConcreteCommand - Penghubung command dan receiver

Contoh

Gambar diatas merupakan contoh implementasi Command Pattern dalam menentukan urutan untuk pembelian dan penjualan saham. Pada kasus ini, Client akan membuat sejumlah permintaan untuk menjual atau membeli saham, oleh karena itu terdapat dua object yang bertindak sebagai ConcreteCommand (BuyStockOrder dan SellStockCommand). Permintaan tersebut akan diterima oleh Agent, maka dari itu ia bertindak selaku Invoker. Setelah permintaan diterima dan dikerjakan, Agent akan menaruh permintaan-permintaan tersebut kedalam StockTrade, maka dari sini bisa disimpulkan bahwa StockTrade berperan sebagai Receiver. Adapun permintaan (Order) itu sendiri berlaku sebagai Command.

Untuk implementasinya di Java, bisa dilihat pada bagian dibawah

public interface Order {     public abstract void execute ( ); } // Receiver class. class StockTrade {     public void buy() {         System.out.println("You want to buy stocks");     }     public void sell() {         System.out.println("You want to sell stocks ");     } } // Invoker. class Agent {     private m_ordersQueue = new ArrayList();     public Agent() {     }         void placeOrder(Order order) {         ordersQueue.addLast(order);         order.execute(ordersQueue.getFirstAndRemove());     }    } //ConcreteCommand Class. class BuyStockOrder implements Order {     private StockTrade stock;     public BuyStockOrder ( StockTrade st) {         stock = st;     }     public void execute( ) {         stock . buy( );     } } //ConcreteCommand Class. class SellStockOrder implements Order {     private StockTrade stock;     public SellStockOrder ( StockTrade st) {         stock = st;     }     public void execute( ) {         stock . sell( );     } } // Client public class Client {     public static void main(String[] args) {         StockTrade stock = new StockTrade();         BuyStockOrder bsc = new BuyStockOrder (stock);         SellStockOrder ssc = new SellStockOrder (stock);         Agent agent = new Agent();         agent.placeOrder(bsc); // Buy Shares         agent.placeOrder(ssc); // Sell Shares     } } //--example output-- //You want to buy stocks //You want to sell stocks

Component-Deployment Diagram

1. Component Diagram

2. Deployment Diagram

Employee Management System

1. Use Case

2. CRC and Class Diagram

3. Activity

4. Sequence

5. Source Code
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<iomanip>
#include<windows.h>
//#include <ctime>
//#include <dos.h>
#include<dos.h>
#include<conio.h>
#include<cstdio>
#define max 20
using namespace std;
struct employee
{
 char name[20];
 long int code;
 char designation[20];
 int exp;
 int age;
};
int num;
employee emp[max],tempemp[max],sortemp[max],sortemp1[max];
int main()
{
 system("cls");
 void build();
 void list();
 void insert();
 void deletes();
 void edit();
 void search();
 void sort();
 char option;
 void menu();
 menu();
 while((option=cin.get())!='q')
 {
  switch(option)
  {
   case 'b':
    build();
    break;
   case 'l':
    list();
    break;
   case 'i':
    insert();
    break;
   case 'd':
    deletes();
    break;
   case 'e':
  edit();
   break;
   case 's':
   search();
   break;
   case 'n':
    sort();
    break;
  }
   menu();
  }
  return 0;
 }
 void menu()
 {
  system("cls");
 // highvideo();
cout<<"      ";
printf("\n*****  Employees Management System 1.0 ***** ");


//normvideo();
cout<<endl;
cout<<"         ";
cout<<"\n\t\t Press  b---->Built The Employee Table ";
cout<<"         ";
cout<<"\n\t\t Press  l---->List The Employee Table  ";
cout<<"         ";
cout<<"\n\t\t Press  i---->Insert New Entry        ";
cout<<"         ";
cout<<"\n\t\t Press  d---->Delete An Entry         ";
cout<<"         ";
cout<<"\n\t\t Press  e---->Edit An Entry           ";
cout<<"         ";
cout<<"\n\t\t Press  s---->Search A Record          ";
cout<<"         ";
cout<<"\n\t\t Press  n---->Sort The Table          ";
cout<<"         ";
cout<<"\n\t\t Press  q---------->Quit Program              ";
cout<<"         ";
cout<<"\n\n \t\t Select Your Option Please ====> ";
}

void build()
{

 system("cls");
// highvideo();
 printf("Build The Table");
 cout<<endl;
 //normvideo();
 cout<<"maximum number of entries  -----  >  20"<<endl;
 cout<<"how many do you want    ----->";
 cin>>num;
 cout<<"Enter The Following Items"<<endl;
 for(int i=0;i<=num-1;i++)
 {
  cout<<" Name ";
  cin>>emp[i].name;
  cout<<"Code ";
  cin>>emp[i].code;
  cout<<"Designation ";
  cin>>emp[i].designation;
  cout<<"Years of Experience ";
  cin>>emp[i].exp;
  cout<<"Age ";
  cin>>emp[i].age;
 }
  cout<<"going to main menu";
 Sleep(500);
}

void  list()
{
 system("cls");
// highvideo();
 printf("       ********List The Table********");
 cout<<endl;
 //normvideo();
 cout<<"     Name Code Designation Years(EXP) Age "<<endl;
 cout<<"    ------------------------------------------------------"<<endl;
 for(int i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<emp[i].name;
  cout<<setw(6)<<emp[i].code;
  cout<<setw(15)<<emp[i].designation;
  cout<<setw(10)<<emp[i].exp;
  cout<<setw(15)<<emp[i].age;
  cout<<endl;
 }
  cout<<"going to main menu";
 getch();
  }
  void insert()
  {
  system("cls");
  int i=num;
  num+=1;
 // highvideo();
  printf("Insert New Record");
  cout<<endl;
  //normvideo();
  cout<<"Enter The Following Items"<<endl;
  cout<<"Name ";
  cin>>emp[i].name;
  cout<<"Code ";
  cin>>emp[i].code;
  cout<<"Designation ";
  cin>>emp[i].designation;
  cout<<"Years of Experience ";
  cin>>emp[i].exp;
  cout<<"Age ";
  cin>>emp[i].age;
  cout<<endl<<endl;
  cout<<"going to main menu";
 Sleep(500);

  }


  void deletes()
  {
   system("cls");
  // highvideo();
   int code;
   int check;
   printf("Delete An Entry");
   //normvideo();
   cout<<endl;
   cout<<"Enter An JobCode To Delete That Entry ";
   cin>>code;
   int i;
   for(i=0;i<=num-1;i++)
   {
    if(emp[i].code==code)
    {
      check=i;
    }
   }
   for(i=0;i<=num-1;i++)
   {
    if(i==check)
    {
    continue;
    }
    else
    {
    if(i>check)
    {
     tempemp[i-1]=emp[i];
    }
    else
    {
     tempemp[i]=emp[i];
    }
     }
   }
  num--;

  for(i=0;i<=num-1;i++)
  {
   emp[i]=tempemp[i];
  }
 }

void edit()
{
 system("cls");
 int jobcode;
// highvideo();
 printf("          Edit An Entry           ");
 cout<<endl;
 cout<<endl;
 int i;
 void editmenu();
 void editname(int);
 void editcode(int);
 void editdes(int);
 void editexp(int);
 void editage(int);
 char option;
 //normvideo();
 cout<<"Enter An jobcode To Edit An Entry---- ";
 cin>>jobcode;
  editmenu();
 for(i=0;i<=num-1;i++)
   {
    if(emp[i].code==jobcode)
    {

while((option=cin.get())!='q')
{
      switch(option)
      {
       case 'n':
  editname(i);
  break;
       case 'c':
  editcode(i);
  break;
       case 'd':
  editdes(i);
  break;
       case 'e':
  editexp(i);
  break;
       case 'a':
 editage(i);
 break;
     }
   editmenu();
    }
  }
  }
  }
  void editmenu()
  {
   system("cls");
   cout<<" What Do You Want To edit";
   cout<<" n--------->Name ";
   cout<<" c--------->Code ";
   cout<<" d--------->Designation";
   cout<<" e--------->Experience ";
   cout<<" a--------->Age        ";
   cout<<"              q----->QUIT                            ";
   cout<<"   Options Please ---->>> ";
  }
  void editname(int i)
  {
     cout<<"Enter New Name-----> ";
     cin>>emp[i].name;
  }
  void editcode(int i)
  {
   cout<<"Enter New Job Code-----> ";
   cin>>emp[i].code;
  }
  void editdes(int i)
  {
   cout<<"enter new designation-----> ";
   cin>>emp[i].designation;
  }
  void editexp(int i)
  {
   cout<<"Enter new Years of Experience";
   cin>>emp[i].exp;
  }
  void editage(int i)
  {
   cout<<"Enter new Age ";
   cin>>emp[i].age;
  }

void search()
{
 system("cls");
 // highvideo();
  printf("Welcome To Search Of Employee Database ");
  //normvideo();
  cout<<endl;
  cout<<endl;
  int jobcode;
  cout<<"You Can Search Only By Jobcode Of An Employee";
  cout<<"Enter Code Of An Employee                    ";
 cin>>jobcode;
 for(int i=0;i<=num-1;i++)
   {
    if(emp[i].code==jobcode)
    {

    cout<<"     Name Code Designation Years(EXP) Age "<<endl;
 cout<<"     ------------------------------------------------------                                  "<<endl;
  cout<<setw(13)<<emp[i].name;
  cout<<setw(6)<<emp[i].code;
  cout<<setw(15)<<emp[i].designation;
  cout<<setw(10)<<emp[i].exp;
  cout<<setw(15)<<emp[i].age;
  cout<<endl;
 }

  }
    cout<<"going to main menu";
 getch();


}

void sort()
{
 system("cls");
// highvideo();
 printf("Sort The Databse By JobCode");
 //normvideo();
 void sortmenu();
 void sortname();
 void sortcode();
 void sortdes();
 void sortexp();
 char option;
 void sortage();

 cout<<endl;
 cout<<endl;
 sortmenu();
 while((option=cin.get())!='q')
 {
  switch(option)
  {
   case 'n':
sortname();
break;
   case 'c':
sortcode();
break;
   case 'd':
sortdes();
break;
   case 'e':
sortexp();
break;
   case 'a':
sortage();
break;
   }
   sortmenu();
  }
 }


 void sortmenu()
 {
    system("cls");
   cout<<" What Do You Want To edit";
   cout<<" n--------->Name         ";
   cout<<" c--------->Code         ";
   cout<<" d--------->Designation  ";
   cout<<" e--------->Experience   ";
   cout<<" a--------->Age          ";
   cout<<"                               q----->QUIT            ";
   cout<<"   Options Please ---->>> ";  }



void sortname()
{
 system("cls");
 int i,j;
 struct employee temp[max];
 for(i=0;i<=num-1;i++)
 {
  sortemp1[i]=emp[i];
 }
 for(i=0;i<=num-1;i++)
  {
   for(j=0;j<=num-1;j++)
   {
    if(strcmp(sortemp1[i].name,sortemp1[j].name)<=0)
    {
     temp[i]=sortemp1[i];
     sortemp1[i]=sortemp1[j];
     sortemp1[j]=temp[i];
    }
   }
 }

 for( i=0;i<=num-1;i++)
   {

    cout<<"     Name Code Designation Years(EXP) Age "<<endl;
 cout<<"     ------------------------------------------------------                                  "<<endl;
 for( i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<sortemp1[i].name;
  cout<<setw(6)<<sortemp1[i].code;
  cout<<setw(15)<<sortemp1[i].designation;
  cout<<setw(10)<<sortemp1[i].exp;
  cout<<setw(15)<<sortemp1[i].age;
  cout<<endl;
 }
  cout<<"Press Any Key To Go Back";
 getch();

} }

void sortcode()
{
 system("cls");
 int i,j;
 struct employee temp[max];
 for(i=0;i<=num-1;i++)
 {
  sortemp1[i]=emp[i];
 }
 for(i=0;i<=num-1;i++)
  {
   for(j=0;j<=num-1;j++)
   {
    if(sortemp1[i].code<sortemp1[j].code)
    {
     temp[i]=sortemp1[i];
     sortemp1[i]=sortemp1[j];
     sortemp1[j]=temp[i];
    }
   }
 }

 for( i=0;i<=num-1;i++)
   {

    cout<<"     Name Code Designation Years(EXP) Age "<<endl;
 cout<<"     ------------------------------------------------------                                  "<<endl;
 for( i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<sortemp1[i].name;
  cout<<setw(6)<<sortemp1[i].code;
  cout<<setw(15)<<sortemp1[i].designation;
  cout<<setw(10)<<sortemp1[i].exp;
  cout<<setw(15)<<sortemp1[i].age;
  cout<<endl;
 }
  cout<<"Press Any Key To Go Back";
 getch();

} }


void sortdes()
{
 system("cls");
 int i,j;
 struct employee temp[max];
 for(i=0;i<=num-1;i++)
 {
  sortemp1[i]=emp[i];
 }
 for(i=0;i<=num-1;i++)
  {
   for(j=0;j<=num-1;j++)
   {
    if(strcmp(sortemp1[i].designation,sortemp1[j].designation)<=0)
    {
     temp[i]=sortemp1[i];
     sortemp1[i]=sortemp1[j];
     sortemp1[j]=temp[i];
    }
   }
 }

 for( i=0;i<=num-1;i++)
   {

    cout<<"     Name Code Designation Years(EXP) Age"<<endl;
 cout<<"     ------------------------------------------------------                                 "<<endl;
 for( i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<sortemp1[i].name;
  cout<<setw(6)<<sortemp1[i].code;
  cout<<setw(15)<<sortemp1[i].designation;
  cout<<setw(10)<<sortemp1[i].exp;
  cout<<setw(15)<<sortemp1[i].age;
  cout<<endl;
 }
  cout<<"Press Any Key To Go Back";
 getch();

} }

void sortage()
{
 system("cls");
 int i,j;
 struct employee temp[max];
 for(i=0;i<=num-1;i++)
 {
  sortemp1[i]=emp[i];
 }
 for(i=0;i<=num-1;i++)
  {
   for(j=0;j<=num-1;j++)
   {
    if(sortemp1[i].age<sortemp1[j].age)
    {
     temp[i]=sortemp1[i];
     sortemp1[i]=sortemp1[j];
     sortemp1[j]=temp[i];
    }
   }
 }

 for( i=0;i<=num-1;i++)
   {

    cout<<"     Name Code Designation Years(EXP) Age"<<endl;
 cout<<"     ------------------------------------------------------                                 "<<endl;
 for( i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<sortemp1[i].name;
  cout<<setw(6)<<sortemp1[i].code;
  cout<<setw(15)<<sortemp1[i].designation;
  cout<<setw(10)<<sortemp1[i].exp;
  cout<<setw(15)<<sortemp1[i].age;
  cout<<endl;
 }
  cout<<"Press Any Key To Go Back";
 getch();

} }


void sortexp()
{
 system("cls");
 int i,j;
 struct employee temp[max];
 for(i=0;i<=num-1;i++)
 {
  sortemp1[i]=emp[i];
 }
 for(i=0;i<=num-1;i++)
  {
   for(j=0;j<=num-1;j++)
   {
    if(sortemp1[i].exp<sortemp1[j].exp)
    {
     temp[i]=sortemp1[i];
     sortemp1[i]=sortemp1[j];
     sortemp1[j]=temp[i];
    }
   }
 }

 for( i=0;i<=num-1;i++)
   {

    cout<<"     Name Code Designation Years(EXP) Age "<<endl;
 cout<<"  ------------------------------------------------------ "<<endl;
 for( i=0;i<=num-1;i++)
 {
  cout<<setw(13)<<sortemp1[i].name;
  cout<<setw(6)<<sortemp1[i].code;
  cout<<setw(15)<<sortemp1[i].designation;
  cout<<setw(10)<<sortemp1[i].exp;
  cout<<setw(15)<<sortemp1[i].age;
  cout<<endl;
 }
  cout<<"Press Any Key To Go Back";
 getch();

} }