|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | +) |
| 6 | + |
| 7 | +/* -------------------------------------------------------------------------- */ |
| 8 | +/* INTERFACES */ |
| 9 | +/* -------------------------------------------------------------------------- */ |
| 10 | + |
| 11 | +type BadVehicle interface { |
| 12 | + Drive() |
| 13 | + Fly() |
| 14 | +} |
| 15 | + |
| 16 | +type AirVehicle interface { |
| 17 | + Fly() |
| 18 | +} |
| 19 | + |
| 20 | +type LandVehicle interface { |
| 21 | + Drive() |
| 22 | +} |
| 23 | + |
| 24 | +type BlackAndWhitePrinter interface { |
| 25 | + Print() |
| 26 | +} |
| 27 | + |
| 28 | +type ColorPrinter interface { |
| 29 | + Print() |
| 30 | +} |
| 31 | + |
| 32 | +type MultifunctionalPrinter interface { |
| 33 | + Print() |
| 34 | + Scan() |
| 35 | + SendFax() |
| 36 | +} |
| 37 | + |
| 38 | +/* -------------------------------------------------------------------------- */ |
| 39 | +/* CLASSES */ |
| 40 | +/* -------------------------------------------------------------------------- */ |
| 41 | + |
| 42 | +/* ------------------------------- BadAirplane ------------------------------ */ |
| 43 | + |
| 44 | +type badAirplane struct{} |
| 45 | + |
| 46 | +func NewBadAirplane() BadVehicle { |
| 47 | + var airplane badAirplane = badAirplane{} |
| 48 | + return &airplane |
| 49 | +} |
| 50 | + |
| 51 | +func (airplane *badAirplane) Drive() { |
| 52 | + panic("Airplanes do not drive") |
| 53 | + |
| 54 | +} |
| 55 | + |
| 56 | +func (airplane *badAirplane) Fly() { |
| 57 | + fmt.Println("The airplane is flying!") |
| 58 | +} |
| 59 | + |
| 60 | +/* --------------------------------- BadCar --------------------------------- */ |
| 61 | + |
| 62 | +type badCar struct{} |
| 63 | + |
| 64 | +func NewBadCar() BadVehicle { |
| 65 | + var car badCar = badCar{} |
| 66 | + return &car |
| 67 | +} |
| 68 | + |
| 69 | +func (car *badCar) Drive() { |
| 70 | + fmt.Println("The car is driving!") |
| 71 | +} |
| 72 | + |
| 73 | +func (car *badCar) Fly() { |
| 74 | + panic("Cars do not fly") |
| 75 | +} |
| 76 | + |
| 77 | +/* ------------------------------ GoodAirplane ------------------------------ */ |
| 78 | + |
| 79 | +type goodAirplane struct{} |
| 80 | + |
| 81 | +func NewGoodAirplane() AirVehicle { |
| 82 | + var airplane goodAirplane = goodAirplane{} |
| 83 | + return &airplane |
| 84 | +} |
| 85 | + |
| 86 | +func (airplane *goodAirplane) Fly() { |
| 87 | + fmt.Println("The airplane is flying!") |
| 88 | +} |
| 89 | + |
| 90 | +/* --------------------------------- GoodCar -------------------------------- */ |
| 91 | + |
| 92 | +type goodCar struct{} |
| 93 | + |
| 94 | +func NewGoodCar() LandVehicle { |
| 95 | + var car goodCar = goodCar{} |
| 96 | + return &car |
| 97 | +} |
| 98 | + |
| 99 | +func (car *goodCar) Drive() { |
| 100 | + fmt.Println("The car is driving!") |
| 101 | +} |
| 102 | + |
| 103 | +/* -------------------------- BlackAndWhitePrinter -------------------------- */ |
| 104 | + |
| 105 | +type blackAndWhitePrinter struct{} |
| 106 | + |
| 107 | +func NewBlackAndWhitePrinter() BlackAndWhitePrinter { |
| 108 | + var printer blackAndWhitePrinter = blackAndWhitePrinter{} |
| 109 | + return &printer |
| 110 | +} |
| 111 | + |
| 112 | +func (printer *blackAndWhitePrinter) Print() { |
| 113 | + fmt.Println("Paper printed in black and white!") |
| 114 | +} |
| 115 | + |
| 116 | +/* ------------------------------ ColorPrinter ------------------------------ */ |
| 117 | + |
| 118 | +type colorPrinter struct{} |
| 119 | + |
| 120 | +func NewColorPrinter() ColorPrinter { |
| 121 | + var printer colorPrinter = colorPrinter{} |
| 122 | + return &printer |
| 123 | +} |
| 124 | + |
| 125 | +func (printer *colorPrinter) Print() { |
| 126 | + fmt.Println("Paper printed in color!") |
| 127 | +} |
| 128 | + |
| 129 | +/* ------------------------- MultifunctionalPrinter ------------------------- */ |
| 130 | + |
| 131 | +type multifunctionalPrinter struct{} |
| 132 | + |
| 133 | +func NewMultifunctionalPrinter() MultifunctionalPrinter { |
| 134 | + var printer multifunctionalPrinter = multifunctionalPrinter{} |
| 135 | + return &printer |
| 136 | +} |
| 137 | + |
| 138 | +func (printer *multifunctionalPrinter) Print() { |
| 139 | + fmt.Println("Paper printed!") |
| 140 | +} |
| 141 | + |
| 142 | +func (printer *multifunctionalPrinter) Scan() { |
| 143 | + fmt.Println("Scan completed!") |
| 144 | +} |
| 145 | + |
| 146 | +func (printer *multifunctionalPrinter) SendFax() { |
| 147 | + fmt.Println("Fax sent!") |
| 148 | +} |
| 149 | + |
| 150 | +/* -------------------------------------------------------------------------- */ |
| 151 | +/* MAIN */ |
| 152 | +/* -------------------------------------------------------------------------- */ |
| 153 | + |
| 154 | +func main() { |
| 155 | + /* |
| 156 | + Interface Segregation Principle (ISP)... |
| 157 | + */ |
| 158 | + |
| 159 | + fmt.Println("Interface Segregation Principle (ISP)...") |
| 160 | + |
| 161 | + fmt.Println("\nBad implementation of Interface Segregation Principle (ISP)...") |
| 162 | + |
| 163 | + fmt.Println("\n```\n" + `type BadVehicle interface { |
| 164 | + Drive() |
| 165 | + Fly() |
| 166 | +} |
| 167 | +
|
| 168 | +type badAirplane struct{} |
| 169 | +
|
| 170 | +func NewBadAirplane() BadVehicle { |
| 171 | + var airplane badAirplane = badAirplane{} |
| 172 | + return &airplane |
| 173 | +} |
| 174 | +
|
| 175 | +func (airplane *badAirplane) Drive() { |
| 176 | + panic("Airplanes do not drive") |
| 177 | +
|
| 178 | +} |
| 179 | +
|
| 180 | +func (airplane *badAirplane) Fly() { |
| 181 | + fmt.Println("The airplane is flying!") |
| 182 | +} |
| 183 | +
|
| 184 | +type badCar struct{} |
| 185 | +
|
| 186 | +func NewBadCar() BadVehicle { |
| 187 | + var car badCar = badCar{} |
| 188 | + return &car |
| 189 | +} |
| 190 | +
|
| 191 | +func (car *badCar) Drive() { |
| 192 | + fmt.Println("The car is driving!") |
| 193 | +} |
| 194 | +
|
| 195 | +func (car *badCar) Fly() { |
| 196 | + panic("Cars do not fly") |
| 197 | +}` + "\n```") |
| 198 | + |
| 199 | + fmt.Println( |
| 200 | + "\nThis is a bad implementation of Interface Segregation Principle (ISP),\n" + |
| 201 | + "because the 'badAirplane' class and the 'badCar' class should not implement\n" + |
| 202 | + "an interface with methods that they are going to never use. So, the implemented\n" + |
| 203 | + "interface ('BadVehicle') is to general for both classes.", |
| 204 | + ) |
| 205 | + |
| 206 | + fmt.Println("\nGood implementation of Interface Segregation Principle (ISP)...") |
| 207 | + |
| 208 | + fmt.Println("\n```\n" + `type AirVehicle interface { |
| 209 | + Fly() |
| 210 | +} |
| 211 | +
|
| 212 | +type LandVehicle interface { |
| 213 | + Drive() |
| 214 | +} |
| 215 | +
|
| 216 | +type goodAirplane struct{} |
| 217 | +
|
| 218 | +func NewGoodAirplane() AirVehicle { |
| 219 | + var airplane goodAirplane = goodAirplane{} |
| 220 | + return &airplane |
| 221 | +} |
| 222 | +
|
| 223 | +func (airplane *goodAirplane) Fly() { |
| 224 | + fmt.Println("The airplane is flying!") |
| 225 | +} |
| 226 | +
|
| 227 | +type goodCar struct{} |
| 228 | +
|
| 229 | +func NewGoodCar() LandVehicle { |
| 230 | + var car goodCar = goodCar{} |
| 231 | + return &car |
| 232 | +} |
| 233 | +
|
| 234 | +func (car *goodCar) Drive() { |
| 235 | + fmt.Println("The car is driving!") |
| 236 | +}` + "\n```") |
| 237 | + |
| 238 | + fmt.Println( |
| 239 | + "\nThis is a good implementation of Interface Segregation Principle (ISP),\n" + |
| 240 | + "because the 'goodAirplane' class and the 'goodCar' class only implements\n" + |
| 241 | + "the necessary methods, without any extras.", |
| 242 | + ) |
| 243 | + |
| 244 | + fmt.Println( |
| 245 | + "\n# ---------------------------------------------------------------------------------- #", |
| 246 | + ) |
| 247 | + |
| 248 | + /* |
| 249 | + Additional challenge... |
| 250 | + */ |
| 251 | + |
| 252 | + fmt.Println("\nAdditional challenge...") |
| 253 | + |
| 254 | + var blackAndWhitePrinter BlackAndWhitePrinter = NewBlackAndWhitePrinter() |
| 255 | + var colorPrinter ColorPrinter = NewColorPrinter() |
| 256 | + var multifunctionalPrinter MultifunctionalPrinter = NewMultifunctionalPrinter() |
| 257 | + |
| 258 | + fmt.Println() |
| 259 | + blackAndWhitePrinter.Print() |
| 260 | + |
| 261 | + fmt.Println() |
| 262 | + colorPrinter.Print() |
| 263 | + |
| 264 | + fmt.Println() |
| 265 | + multifunctionalPrinter.Print() |
| 266 | + |
| 267 | + fmt.Println() |
| 268 | + multifunctionalPrinter.Scan() |
| 269 | + |
| 270 | + fmt.Println() |
| 271 | + multifunctionalPrinter.SendFax() |
| 272 | +} |
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