Added Composite Pattern

README.md

@@ -17,7 +17,7 @@ Tested on: GNU Fortran (GCC) 4.8.
 #### Structural Patterns
 - [X] Adapter
 - [X] Bridge
-- [ ] Composite
+- [X] Composite
 - [ ] Decorator
 - [ ] Façade
 - [ ] Flyweight

structural/composite/composite_main.f90

@@ -0,0 +1,31 @@
+!Copyright (c) 2013 Farhan J. Khan
+!THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+!IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+!FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+!COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+!IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+!CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+!Main Program
+program composite_main
+	use composite_module
+	implicit none
+
+	!Employees
+	type(employee) :: manager
+	type(employee) :: assistant_manager1
+	type(employee) :: assistant_manager2
+	type(employee) :: regular_employee
+
+	manager = employee('Khan')
+	assistant_manager1 = employee('Jamal')
+	assistant_manager2 = employee('Farhan')
+	regular_employee = employee('Zinnia')
+
+	!Add subordinates and validate by printing them
+	call manager%add_subordinate(assistant_manager1)	
+	call manager%add_subordinate(assistant_manager2)	
+	call manager%print_subordinates
+	call assistant_manager1%add_subordinate(regular_employee)
+	call assistant_manager1%print_subordinates
+end program composite_main

structural/composite/composite_module.f90

@@ -0,0 +1,83 @@
+!Copyright (c) 2013 Farhan J. Khan
+!THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+!IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+!FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+!COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+!IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+!CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+!Composite pattern implementation
+module composite_module
+	implicit none
+
+	!employee contains list of employees
+	type employee
+		character(30) :: name
+		type(employee), pointer :: next => null()
+	    type(employee), pointer :: list=>null(), current=>null(), previous=>null()
+		integer :: N = 0
+		contains
+			procedure :: print_employee_name => print_employee_name_impl
+			procedure :: add_subordinate => add_subordinate_impl
+			procedure :: remove_last_subordinate => remove_last_subordinate_impl
+			procedure :: print_subordinates => print_subordinates_impl
+	end type employee
+
+	!Constructor for initializing the employee
+	interface employee
+ 	    module procedure init_employee
+    end interface
+
+contains
+
+    type(employee) function init_employee(this)
+		class(employee), intent(inout) :: this
+		nullify(init_employee%list)   ! Initialize list to point to no target.
+	end function
+
+	subroutine print_employee_name_impl(this)
+		class(employee), intent(in) :: this
+		print *, this%name
+	end subroutine print_employee_name_impl
+
+	subroutine add_subordinate_impl(this, new_employee)
+		class(employee), intent(inout) :: this
+		type(employee), intent(in) :: new_employee
+
+		! Add the 1st element as a special case.
+	   if (.not. associated(this%list)) then
+		   allocate(this%list)
+	      this%list = new_employee
+	      nullify(this%list%next)
+		  this%current => this%list
+	  else
+		  allocate(this%current%next)
+		 this%current%next = new_employee
+		 nullify(this%current%next%next)
+		 this%current => this%current%next
+     end if
+
+	end subroutine add_subordinate_impl
+
+	subroutine remove_last_subordinate_impl(this)
+		class(employee), intent(inout) :: this
+		this%current = this%current%previous
+	end subroutine remove_last_subordinate_impl
+
+	subroutine print_subordinates_impl(this)
+		class(employee), intent(in) :: this
+		! Output the list
+
+ 		  type(employee), pointer :: temp_cur
+		  type(employee), pointer :: temp_prev
+
+			  print *, 'List of subordinates:'
+		   temp_cur => this%list
+		   do while ( associated(temp_cur) )
+		      print *, temp_cur%name
+		      temp_prev => temp_cur
+		      temp_cur => temp_cur%next
+		   end do
+	 end subroutine print_subordinates_impl
+
+end module composite_module