Updated flyweight

Author: arkada38

examples/structural_flyweight_parking.rs

@@ -0,0 +1,23 @@
+use design_patterns::structural::flyweight::parking::{
+    car::car_type::{Body, Colour},
+    Parking,
+};
+
+fn main() {
+    use Body::{Coupe, Sedan, Truck};
+    use Colour::{Black, Red, Yellow};
+
+    let mut parking = Parking::new();
+    parking.add_car("NFS MW", 13, Coupe, Red);
+    parking.add_car("MW2017", 15, Truck, Yellow);
+    parking.add_car("BIG11", 37, Sedan, Black);
+    parking.add_car("KING", 64, Coupe, Red);
+    parking.add_car("MAN", 73, Coupe, Red);
+    parking.add_car("TE64G", 18, Truck, Yellow);
+    parking.add_car("SMILE", 39, Sedan, Black);
+    parking.add_car("DARK01", 24, Truck, Black);
+    parking.add_car("DARK03", 25, Truck, Black);
+    parking.add_car("DARK05", 26, Truck, Black);
+
+    parking.print();
+}

src/structural/flyweight/mod.rs

@@ -0,0 +1,11 @@
+//! # Flyweight
+//!
+//! ## Type
+//!
+//! Structural
+//!
+//! ## Description
+//!
+//! Use sharing to support large numbers of fine grained objects efficiently.
+
+pub mod parking;

src/structural/flyweight/parking/car/car_factory.rs

@@ -0,0 +1,37 @@
+use super::car_type::{Body, CarType, Colour};
+
+pub struct CarFactory {
+    car_types: Vec<CarType>,
+}
+
+impl CarFactory {
+    pub fn new() -> CarFactory {
+        CarFactory {
+            car_types: Vec::new(),
+        }
+    }
+
+    pub fn get_car_type_id(&mut self, body: Body, colour: Colour) -> u8 {
+        let position = self
+            .car_types
+            .iter()
+            .position(|ref r| r.body == body && r.colour == colour);
+
+        match position {
+            Some(x) => x as u8,
+            None => {
+                let car_type = CarType::new(body, colour);
+                self.car_types.push(car_type);
+                (self.car_types.len() - 1) as u8
+            }
+        }
+    }
+
+    pub fn get_car_type(&mut self, id: u8) -> Option<&CarType> {
+        self.car_types.get(id as usize)
+    }
+
+    pub fn print(&self) {
+        println!("Number of car types: {}", self.car_types.len());
+    }
+}

src/structural/flyweight/parking/car/car_type.rs

@@ -0,0 +1,24 @@
+pub struct CarType {
+    pub body: Body,
+    pub colour: Colour,
+}
+
+impl CarType {
+    pub fn new(body: Body, colour: Colour) -> CarType {
+        CarType { body, colour }
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub enum Body {
+    Sedan,
+    Coupe,
+    Truck,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum Colour {
+    Black,
+    Yellow,
+    Red,
+}

src/structural/flyweight/parking/car/mod.rs

@@ -0,0 +1,27 @@
+pub mod car_factory;
+pub mod car_type;
+
+use car_type::CarType;
+
+pub struct Car {
+    pub license_plate: String,
+    pub parking_place_number: u8,
+    pub car_type_id: u8,
+}
+
+impl Car {
+    pub fn new(license_plate: String, parking_place_number: u8, car_type_id: u8) -> Car {
+        Car {
+            license_plate,
+            parking_place_number,
+            car_type_id,
+        }
+    }
+
+    pub fn print(&self, car_type: &CarType) {
+        println!(
+            "{} - {:?} {:?}, {}",
+            self.parking_place_number, car_type.colour, car_type.body, self.license_plate
+        )
+    }
+}

src/structural/flyweight/parking/mod.rs

@@ -0,0 +1,43 @@
+pub mod car;
+
+use car::car_factory::CarFactory;
+use car::car_type::{Body, Colour};
+use car::Car;
+
+pub struct Parking {
+    cars: Vec<Car>,
+    car_factory: CarFactory,
+}
+
+impl Parking {
+    pub fn new() -> Parking {
+        Parking {
+            cars: Vec::new(),
+            car_factory: CarFactory::new(),
+        }
+    }
+
+    pub fn add_car(
+        &mut self,
+        license_plate: &str,
+        parking_place_number: u8,
+        body: Body,
+        colour: Colour,
+    ) {
+        self.cars.push(Car::new(
+            license_plate.to_string(),
+            parking_place_number,
+            self.car_factory.get_car_type_id(body, colour),
+        ));
+    }
+
+    pub fn print(&mut self) {
+        for car in &self.cars {
+            let car_type = self.car_factory.get_car_type(car.car_type_id).unwrap();
+            car.print(car_type);
+        }
+
+        println!("\nNumber of cars: {}", self.cars.len());
+        self.car_factory.print();
+    }
+}

src/structural/mod.rs

@@ -15,3 +15,4 @@ pub mod bridge;
 pub mod composite;
 pub mod decorator;
 pub mod facade;
+pub mod flyweight;