Command Pattern (Design Pattern)

Here is sample code to understand command pattern

Hierarchy is as follows:
Equipments: Laptop, Mobile Phone, TabletPC
Action: TurnOn, TurnOff

Equipment.java

package com.manan.testlab;
public interface Equipment {
public boolean turnOn();
public boolean turnOff();
}

Laptop.java

package com.manan.testlab;
public class Laptop implements Equipment {

@Override
public boolean turnOn() {
System.out.println("Turn On Laptop..");
return true;
}

@Override
public boolean turnOff() {
System.out.println("Turn Off Laptop..");
return true;
}

}

MobilePhone.java

package com.manan.testlab;
public class MobilePhone implements Equipment {

@Override
public boolean turnOn() {
System.out.println("Turn On Mobile..");
return true;
}

@Override
public boolean turnOff() {
System.out.println("Turn Off Mobile..");
return true;
}
}

TabletPC.java

package com.manan.testlab;
public class TabletPC implements Equipment {

@Override
public boolean turnOn() {
System.out.println("Turn On TabletPC..");
return true;
}

@Override
public boolean turnOff() {
System.out.println("Turn Off TabletPC..");
return true;
}
}

Command.java

package com.manan.testlab;
public interface Command {
public void execute();
public void setEquipment(Equipment pEquip); //optional
}

SwitchOn.java

package com.manan.testlab;
public class SwitchOn implements Command {

Equipment e;

public SwitchOn(){
}

public SwitchOn(Equipment pEquip){
this.e = pEquip;
}

public void setEquipment(Equipment pEquip){
this.e = pEquip;
}

@Override
public void execute() {
e.turnOn();
}

}

SwitchOff.java

package com.manan.testlab;

public class SwitchOff implements Command {

Equipment e;

public SwitchOff(){

}

public SwitchOff(Equipment pEquip){

this.e = pEquip;

}

public void setEquipment(Equipment pEquip){

this.e = pEquip;

}

@Override

public void execute() {

e.turnOff();

}

}

CommandTest.java

package com.manan.testlab;

public class CommandTest {

public static void main(String args[]){

Equipment laptop = new Laptop();

Equipment mob = new MobilePhone(); 

Equipment tab = new TabletPC();

Command on = new SwitchOn();

on.setEquipment(laptop);

on.execute();

on.setEquipment(mob);

on.execute();

on.setEquipment(tab);

on.execute();

Command off = new SwitchOff();

off.setEquipment(laptop);

off.execute();

off.setEquipment(mob);

off.execute();

off.setEquipment(tab);

off.execute();

}

}

Output:

Turn On Laptop..
Turn On Mobile..
Turn On TabletPC..
Turn Off Laptop..
Turn Off Mobile..
Turn Off TabletPC..