CS511 Homework 3 Solution

ts. Excerpts of code presented in class can be used.
Assignments from previous offerings of the course must not be reused. Violations will be penalized appropriately.
2 Assignment
The aim of this assignment is to get familiar with the functional fragment of Erlang and to learn how to work with some of the data structures provided by the language; notably lists, maps, and records.
• shipping.hrl. The Erlang header file for the assignment. It contains all the record declarations you should need to complete this assignment. These are described in further detail below.
• shipping.erl. The module file that includes all the functions that need to be completed. This is the file you will be editing.
2.0.1 Shipping Header File (shipping.hrl)
• Ship This record contains the fields:
· name a string value
· id a unique integer value
· containercap the maximum number of containers that a ship can hold
• Container This record contains the fields:
· id a unique integer value · weight any positive integer value
• Port This record contains the fields:
· name a string value
· id a unique integer value
· docks a list of docks for the port. A dock can be represented by an unique integer or a character and is only required to be unique at a given port (i.e. Port “New York”, Dock ‘A’ and Port “Los Angeles”, Dock ‘A’ are both valid)
· containercap the maximum number of containers that a ship can hold
• Shipping State This record contains the fields:
· ships a list of the ship records currently in the system
· containers a list of the container records currently in the system
· ports a list of the port records currently in the system
· shiplocations a tuple containing a portid, dockid, and shipid (i.e. (1,’A’,3)) if port 1, dock ‘A’ contains ship 3
· shipinventory a map that takes a ship id and maps it to the list of containers ids on that ship.
· portinventory a map that takes a port id and maps it to the list of containers ids at that port.
3 Shipping Module
We next describe each of the functions you are asked to implement. All of them have to be defined in shipping.erl.
To illustrate some of the functions described below we will use a sample shipping company
{ok,shipping}
2> rr(shipping).
[container,port,ship,shipping_state]
1. getship(ShippingState, ShipID)
This method returns a ship record for the given id. For example, shipping:get_ship(shipping:shipco(),1) will return the ship whose id is 1. If the ship does not exist, it returns the atom error.
3> shipping:get_ship(shipping:shipco(),1).
#ship{id = 1,name = "Santa Maria",container_cap = 20} 4> shipping:get_ship(shipping:shipco(),7). error
2. getcontainer(ShippingState, ContainerID)
This method returns a container record for the given id. It returns the atom error if the container id does not exist. For example:
5> shipping:get_container(shipping:shipco(),4).
#container{id = 4,weight = 62}
6> shipping:get_container(shipping:shipco(),47). error
3. getport(ShippingState, PortID)
This method returns a port records for the given id. It returns the atom error if the port id does not exist. For example:
7> shipping:get_port(shipping:shipco(),3).
#port{id = 3,name = "Miami", docks = [’A’,’B’,’C’,’D’], container_cap = 200}
8> shipping:get_port(shipping:shipco(),12).
error
4. getoccupieddocks(ShippingState, PortID)
This method returns a list of all the occupied docks for a given port. It returns the empty list if the port id does not exist. For example:
9> shipping:get_occupied_docks(shipping:shipco(),3).
[’C’]
10> shipping:get_occupied_docks(shipping:shipco(),23).
[]
5. getshiplocation(ShippingState, ShipID)
This method returns the location, {PortID, DockID}, of a given ship. It returns the atom error if the ship id does not exist. For example:
11> shipping:get_ship_location(shipping:shipco(),3).
{1,’A’}
12> shipping:get_ship_location(shipping:shipco(),23). error
6. getcontainer weight(ShippingState, ContainerIDs)
This method returns the total weight of all of the container ids in the list ContainerIDs. It returns the atom error if any of the container Ids does not exist.
13> shipping:get_container_weight(shipping:shipco(),[3,5]).
243
14> shipping:get_container_weight(shipping:shipco(),[89,3,5]). error
7. getshipweight(ShippingState, ShipID)
This method returns the total weight of a ship, measured by the total weight of the ship’s containers. It returns the atom error if ship Id does not exist.
15> shipping:get_ship_weight(shipping:shipco(),2).
676 16> shipping:get_ship_weight(shipping:shipco(),22). error
8. load ship(ShippingState, ShipID, ContainerIDs)
This method returns a shipping state in which the containers in the list of ContainerIDs are moved from a port to the ship with the given ShipID. Make sure that all the containers are at the same port as the ship they are loading onto. In the case that loading the ship would put the ship over capacity, return an atom error and do not add any containers to the ship. Also return error if there are container IDs that aren’t in the same port as the ship. Here is an example. Notice how containers 16, 18 and 20 have been removed from dock 1 and loaded onto ship 1.
10> shipping:load_ship(shipping:shipco(), 1, [16,18,20]).
{ok,#shipping_state{ ships = [#ship{id = 1,name = "Santa Maria",container_cap = 20},
#ship{id = 2,name = "Nina",container_cap = 20},
#ship{id = 3,name = "Pinta",container_cap = 20},
#ship{id = 4,name = "SS Minnow", container_cap = 20},
#ship{id = 5,name = "Sir Leaks-A-Lot",container_cap = 20}],
containers = [...], %% not shown ports = [#port{id = 1,name = "New York", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 2,name = "San Francisco", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 3,name = "Miami", docks = [’A’,’B’,’C’,’D’], container_cap = 200}],
ship_locations = [{1,’B’,1}, {1,’A’,3},
{3,’C’,2},
{2,’D’,4},
{2,’B’,5}],
ship_inventory = #{1 => [14,15,9,2,6,16,18,20], %% loaded here
2 => [1,3,4,13],
3 => [],
4 => [2,8,11,7],
5 => [5,10,12]},
port_inventory = #{1 => [17,19], %% removed from port 1
2 => [21,22,23,24,25],
3 => [26,27,28,29,30]}}}
9. unload shipall(ShippingState, ShipID)
This method returns a shipping state in which all of the containers that are on a given ship are offloaded to the port in which the ship is docked. In the case that offloading to a port would put the port over capacity, return an error and do not unload any containers to the port.
11> shipping:unload_ship_all(shipping:shipco(), 2).
{ok,#shipping_state{ ships = [#ship{id = 1,name = "Santa Maria",container_cap = 20},
#ship{id = 2,name = "Nina",container_cap = 20},
#ship{id = 3,name = "Pinta",container_cap = 20},
#ship{id = 4,name = "SS Minnow",container_cap = 20},
#ship{id = 5,name = "Sir Leaks-A-Lot",container_cap = 20}],
containers = [...], %% not shown ports = [#port{id = 1,name = "New York", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 2,name = "San Francisco", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 3,name = "Miami", docks = [’A’,’B’,’C’,’D’], container_cap = 200}],
ship_locations = [{1,’B’,1},
{1,’A’,3},
{3,’C’,2},
{2,’D’,4},
{2,’B’,5}],
ship_inventory = #{1 => [14,15,9,2,6],
2 => [], %% no more containers
3 => [],
4 => [2,8,11,7],
5 => [5,10,12]},
port_inventory = #{1 => [16,17,18,19,20], 2 => [21,22,23,24,25],
3 => [26,27,28,29,30,1,3,4,13]} %% loaded here
}}
10. unload ship(ShippingState, ShipID, ContainerIDs)
This method returns a shipping state in which the given containers on a ship are offloaded to the port in which the ship is docked. Make sure that all the containers are located on the ship. In the case that offloading to a port would put the port over capacity, return an error and do not offload any containers to the port.
12> shipping:unload_ship(shipping:shipco(), 1, [2,16,18]).
The given conatiners are not all on the same ship... error
13> shipping:unload_ship(shipping:shipco(), 1, [14,2]).
{ok,#shipping_state{ ships = [#ship{id = 1,name = "Santa Maria",container_cap = 20},
#ship{id = 2,name = "Nina",container_cap = 20},
#ship{id = 3,name = "Pinta",container_cap = 20},
#ship{id = 4,name = "SS Minnow",container_cap = 20},
#ship{id = 5,name = "Sir Leaks-A-Lot",container_cap = 20}],
containers = [...], %% not shown ports = [#port{id = 1,name = "New York", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 2,name = "San Francisco", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 3,name = "Miami", docks = [’A’,’B’,’C’,’D’], container_cap = 200}],
ship_locations = [{1,’B’,1}, {1,’A’,3},
{3,’C’,2},
{2,’D’,4},
{2,’B’,5}],
ship_inventory = #{1 => [15,9,6], %% removed from here
2 => [1,3,4,13],
3 => [],
4 => [2,8,11,7],
5 => [5,10,12]},
port_inventory = #{1 => [16,17,18,19,20,14,2], %% placed here
2 => [21,22,23,24,25],
3 => [26,27,28,29,30]}}}
11. setsail(ShippingState, ShipID, {PortID, Dock})
This method changes the given ship’s port and dock location to the new port and dock location. Be sure to check whether or not the new port and dock is occupied. If it is, then return the atom error.
14> shipping:set_sail(shipping:shipco(), 4, {2,’B’}).
error
15> shipping:set_sail(shipping:shipco(), 4, {3,’A’}).
{ok,#shipping_state{ ships = [#ship{id = 1,name = "Santa Maria",container_cap = 20},
#ship{id = 2,name = "Nina",container_cap = 20},
#ship{id = 3,name = "Pinta",container_cap = 20},
#ship{id = 4,name = "SS Minnow",container_cap = 20},
#ship{id = 5,name = "Sir Leaks-A-Lot",container_cap = 20}],
containers = [...], %% not shown ports = [#port{id = 1,name = "New York", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 2,name = "San Francisco", docks = [’A’,’B’,’C’,’D’], container_cap = 200},
#port{id = 3,name = "Miami", docks = [’A’,’B’,’C’,’D’], container_cap = 200}],
ship_locations = [{1,’B’,1}, {1,’A’,3},
{3,’C’,2},
{3,’A’,4}, %% new port and dock {2,’B’,5}],
ship_inventory = #{1 => [14,15,9,2,6],
2 => [1,3,4,13],
3 => [],
4 => [2,8,11,7],
5 => [5,10,12]},
port_inventory = #{1 => [16,17,18,19,20], 2 => [21,22,23,24,25],
3 => [26,27,28,29,30]}}}
4 Your Task
Your task is to complete all the functions in shipping.erl as mentioned above. You DO NOT have to touch shipping.hrl. Some example modules to help you complete some of these functions would be the lists and maps modules.
5 Submission Instructions
Submit a file hw3.zip through Canvas containing all the files included in the stub but where all required operations have been implemented.