├── .gitignore ├── Cargo.toml ├── LICENSE ├── README.md ├── behavioral ├── chain_of_responsibility.rs ├── command.rs ├── iterator.rs ├── observer.rs ├── state.rs └── strategy.rs ├── creational ├── abstract_factory.rs ├── builder.rs ├── factory.rs └── singleton.rs ├── rust-logo.png └── structural ├── adapter.rs ├── decorator.rs └── proxy.rs /.gitignore: -------------------------------------------------------------------------------- 1 | # Generated by Cargo 2 | # will have compiled files and executables 3 | /target/ 4 | 5 | # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries 6 | # More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html 7 | Cargo.lock 8 | 9 | # These are backup files generated by rustfmt 10 | **/*.rs.bk 11 | .vscode/ 12 | .DS_Store 13 | .history 14 | .idea 15 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "rust_design_pattern" 3 | version = "0.1.0" 4 | authors = ["lpxxn "] 5 | edition = "2018" 6 | 7 | [[bin]] 8 | name = "factory" 9 | path = "./creational/factory.rs" 10 | 11 | [[bin]] 12 | name = "abstract_factory" 13 | path = "./creational/abstract_factory.rs" 14 | 15 | [[bin]] 16 | name = "builder" 17 | path = "./creational/builder.rs" 18 | 19 | [[bin]] 20 | name = "strategy" 21 | path = "./behavioral/strategy.rs" 22 | 23 | [[bin]] 24 | name = "state" 25 | path = "./behavioral/state.rs" 26 | 27 | [[bin]] 28 | name = "command" 29 | path = "./behavioral/command.rs" 30 | 31 | [[bin]] 32 | name = "iterator" 33 | path = "./behavioral/iterator.rs" 34 | 35 | [[bin]] 36 | name = "observer" 37 | path = "./behavioral/observer.rs" 38 | 39 | [[bin]] 40 | name = "chain_of_responsibility" 41 | path = "./behavioral/chain_of_responsibility.rs" 42 | 43 | [[bin]] 44 | name = "adapter" 45 | path = "./structural/adapter.rs" 46 | 47 | [[bin]] 48 | name = "decorator" 49 | path = "./structural/decorator.rs" 50 | 51 | [[bin]] 52 | name = "proxy" 53 | path = "./structural/proxy.rs" 54 | 55 | [[bin]] 56 | name = "singleton" 57 | path = "./creational/singleton.rs" 58 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Mozilla Public License Version 2.0 2 | ================================== 3 | 4 | 1. Definitions 5 | -------------- 6 | 7 | 1.1. "Contributor" 8 | means each individual or legal entity that creates, contributes to 9 | the creation of, or owns Covered Software. 10 | 11 | 1.2. "Contributor Version" 12 | means the combination of the Contributions of others (if any) used 13 | by a Contributor and that particular Contributor's Contribution. 14 | 15 | 1.3. "Contribution" 16 | means Covered Software of a particular Contributor. 17 | 18 | 1.4. "Covered Software" 19 | means Source Code Form to which the initial Contributor has attached 20 | the notice in Exhibit A, the Executable Form of such Source Code 21 | Form, and Modifications of such Source Code Form, in each case 22 | including portions thereof. 23 | 24 | 1.5. "Incompatible With Secondary Licenses" 25 | means 26 | 27 | (a) that the initial Contributor has attached the notice described 28 | in Exhibit B to the Covered Software; or 29 | 30 | (b) that the Covered Software was made available under the terms of 31 | version 1.1 or earlier of the License, but not also under the 32 | terms of a Secondary License. 33 | 34 | 1.6. "Executable Form" 35 | means any form of the work other than Source Code Form. 36 | 37 | 1.7. "Larger Work" 38 | means a work that combines Covered Software with other material, in 39 | a separate file or files, that is not Covered Software. 40 | 41 | 1.8. "License" 42 | means this document. 43 | 44 | 1.9. "Licensable" 45 | means having the right to grant, to the maximum extent possible, 46 | whether at the time of the initial grant or subsequently, any and 47 | all of the rights conveyed by this License. 48 | 49 | 1.10. "Modifications" 50 | means any of the following: 51 | 52 | (a) any file in Source Code Form that results from an addition to, 53 | deletion from, or modification of the contents of Covered 54 | Software; or 55 | 56 | (b) any new file in Source Code Form that contains any Covered 57 | Software. 58 | 59 | 1.11. "Patent Claims" of a Contributor 60 | means any patent claim(s), including without limitation, method, 61 | process, and apparatus claims, in any patent Licensable by such 62 | Contributor that would be infringed, but for the grant of the 63 | License, by the making, using, selling, offering for sale, having 64 | made, import, or transfer of either its Contributions or its 65 | Contributor Version. 66 | 67 | 1.12. "Secondary License" 68 | means either the GNU General Public License, Version 2.0, the GNU 69 | Lesser General Public License, Version 2.1, the GNU Affero General 70 | Public License, Version 3.0, or any later versions of those 71 | licenses. 72 | 73 | 1.13. "Source Code Form" 74 | means the form of the work preferred for making modifications. 75 | 76 | 1.14. "You" (or "Your") 77 | means an individual or a legal entity exercising rights under this 78 | License. For legal entities, "You" includes any entity that 79 | controls, is controlled by, or is under common control with You. For 80 | purposes of this definition, "control" means (a) the power, direct 81 | or indirect, to cause the direction or management of such entity, 82 | whether by contract or otherwise, or (b) ownership of more than 83 | fifty percent (50%) of the outstanding shares or beneficial 84 | ownership of such entity. 85 | 86 | 2. License Grants and Conditions 87 | -------------------------------- 88 | 89 | 2.1. Grants 90 | 91 | Each Contributor hereby grants You a world-wide, royalty-free, 92 | non-exclusive license: 93 | 94 | (a) under intellectual property rights (other than patent or trademark) 95 | Licensable by such Contributor to use, reproduce, make available, 96 | modify, display, perform, distribute, and otherwise exploit its 97 | Contributions, either on an unmodified basis, with Modifications, or 98 | as part of a Larger Work; and 99 | 100 | (b) under Patent Claims of such Contributor to make, use, sell, offer 101 | for sale, have made, import, and otherwise transfer either its 102 | Contributions or its Contributor Version. 103 | 104 | 2.2. Effective Date 105 | 106 | The licenses granted in Section 2.1 with respect to any Contribution 107 | become effective for each Contribution on the date the Contributor first 108 | distributes such Contribution. 109 | 110 | 2.3. Limitations on Grant Scope 111 | 112 | The licenses granted in this Section 2 are the only rights granted under 113 | this License. No additional rights or licenses will be implied from the 114 | distribution or licensing of Covered Software under this License. 115 | Notwithstanding Section 2.1(b) above, no patent license is granted by a 116 | Contributor: 117 | 118 | (a) for any code that a Contributor has removed from Covered Software; 119 | or 120 | 121 | (b) for infringements caused by: (i) Your and any other third party's 122 | modifications of Covered Software, or (ii) the combination of its 123 | Contributions with other software (except as part of its Contributor 124 | Version); or 125 | 126 | (c) under Patent Claims infringed by Covered Software in the absence of 127 | its Contributions. 128 | 129 | This License does not grant any rights in the trademarks, service marks, 130 | or logos of any Contributor (except as may be necessary to comply with 131 | the notice requirements in Section 3.4). 132 | 133 | 2.4. Subsequent Licenses 134 | 135 | No Contributor makes additional grants as a result of Your choice to 136 | distribute the Covered Software under a subsequent version of this 137 | License (see Section 10.2) or under the terms of a Secondary License (if 138 | permitted under the terms of Section 3.3). 139 | 140 | 2.5. Representation 141 | 142 | Each Contributor represents that the Contributor believes its 143 | Contributions are its original creation(s) or it has sufficient rights 144 | to grant the rights to its Contributions conveyed by this License. 145 | 146 | 2.6. Fair Use 147 | 148 | This License is not intended to limit any rights You have under 149 | applicable copyright doctrines of fair use, fair dealing, or other 150 | equivalents. 151 | 152 | 2.7. Conditions 153 | 154 | Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted 155 | in Section 2.1. 156 | 157 | 3. Responsibilities 158 | ------------------- 159 | 160 | 3.1. Distribution of Source Form 161 | 162 | All distribution of Covered Software in Source Code Form, including any 163 | Modifications that You create or to which You contribute, must be under 164 | the terms of this License. You must inform recipients that the Source 165 | Code Form of the Covered Software is governed by the terms of this 166 | License, and how they can obtain a copy of this License. You may not 167 | attempt to alter or restrict the recipients' rights in the Source Code 168 | Form. 169 | 170 | 3.2. Distribution of Executable Form 171 | 172 | If You distribute Covered Software in Executable Form then: 173 | 174 | (a) such Covered Software must also be made available in Source Code 175 | Form, as described in Section 3.1, and You must inform recipients of 176 | the Executable Form how they can obtain a copy of such Source Code 177 | Form by reasonable means in a timely manner, at a charge no more 178 | than the cost of distribution to the recipient; and 179 | 180 | (b) You may distribute such Executable Form under the terms of this 181 | License, or sublicense it under different terms, provided that the 182 | license for the Executable Form does not attempt to limit or alter 183 | the recipients' rights in the Source Code Form under this License. 184 | 185 | 3.3. Distribution of a Larger Work 186 | 187 | You may create and distribute a Larger Work under terms of Your choice, 188 | provided that You also comply with the requirements of this License for 189 | the Covered Software. If the Larger Work is a combination of Covered 190 | Software with a work governed by one or more Secondary Licenses, and the 191 | Covered Software is not Incompatible With Secondary Licenses, this 192 | License permits You to additionally distribute such Covered Software 193 | under the terms of such Secondary License(s), so that the recipient of 194 | the Larger Work may, at their option, further distribute the Covered 195 | Software under the terms of either this License or such Secondary 196 | License(s). 197 | 198 | 3.4. Notices 199 | 200 | You may not remove or alter the substance of any license notices 201 | (including copyright notices, patent notices, disclaimers of warranty, 202 | or limitations of liability) contained within the Source Code Form of 203 | the Covered Software, except that You may alter any license notices to 204 | the extent required to remedy known factual inaccuracies. 205 | 206 | 3.5. Application of Additional Terms 207 | 208 | You may choose to offer, and to charge a fee for, warranty, support, 209 | indemnity or liability obligations to one or more recipients of Covered 210 | Software. However, You may do so only on Your own behalf, and not on 211 | behalf of any Contributor. You must make it absolutely clear that any 212 | such warranty, support, indemnity, or liability obligation is offered by 213 | You alone, and You hereby agree to indemnify every Contributor for any 214 | liability incurred by such Contributor as a result of warranty, support, 215 | indemnity or liability terms You offer. You may include additional 216 | disclaimers of warranty and limitations of liability specific to any 217 | jurisdiction. 218 | 219 | 4. Inability to Comply Due to Statute or Regulation 220 | --------------------------------------------------- 221 | 222 | If it is impossible for You to comply with any of the terms of this 223 | License with respect to some or all of the Covered Software due to 224 | statute, judicial order, or regulation then You must: (a) comply with 225 | the terms of this License to the maximum extent possible; and (b) 226 | describe the limitations and the code they affect. Such description must 227 | be placed in a text file included with all distributions of the Covered 228 | Software under this License. Except to the extent prohibited by statute 229 | or regulation, such description must be sufficiently detailed for a 230 | recipient of ordinary skill to be able to understand it. 231 | 232 | 5. Termination 233 | -------------- 234 | 235 | 5.1. The rights granted under this License will terminate automatically 236 | if You fail to comply with any of its terms. However, if You become 237 | compliant, then the rights granted under this License from a particular 238 | Contributor are reinstated (a) provisionally, unless and until such 239 | Contributor explicitly and finally terminates Your grants, and (b) on an 240 | ongoing basis, if such Contributor fails to notify You of the 241 | non-compliance by some reasonable means prior to 60 days after You have 242 | come back into compliance. Moreover, Your grants from a particular 243 | Contributor are reinstated on an ongoing basis if such Contributor 244 | notifies You of the non-compliance by some reasonable means, this is the 245 | first time You have received notice of non-compliance with this License 246 | from such Contributor, and You become compliant prior to 30 days after 247 | Your receipt of the notice. 248 | 249 | 5.2. If You initiate litigation against any entity by asserting a patent 250 | infringement claim (excluding declaratory judgment actions, 251 | counter-claims, and cross-claims) alleging that a Contributor Version 252 | directly or indirectly infringes any patent, then the rights granted to 253 | You by any and all Contributors for the Covered Software under Section 254 | 2.1 of this License shall terminate. 255 | 256 | 5.3. In the event of termination under Sections 5.1 or 5.2 above, all 257 | end user license agreements (excluding distributors and resellers) which 258 | have been validly granted by You or Your distributors under this License 259 | prior to termination shall survive termination. 260 | 261 | ************************************************************************ 262 | * * 263 | * 6. Disclaimer of Warranty * 264 | * ------------------------- * 265 | * * 266 | * Covered Software is provided under this License on an "as is" * 267 | * basis, without warranty of any kind, either expressed, implied, or * 268 | * statutory, including, without limitation, warranties that the * 269 | * Covered Software is free of defects, merchantable, fit for a * 270 | * particular purpose or non-infringing. The entire risk as to the * 271 | * quality and performance of the Covered Software is with You. * 272 | * Should any Covered Software prove defective in any respect, You * 273 | * (not any Contributor) assume the cost of any necessary servicing, * 274 | * repair, or correction. This disclaimer of warranty constitutes an * 275 | * essential part of this License. No use of any Covered Software is * 276 | * authorized under this License except under this disclaimer. * 277 | * * 278 | ************************************************************************ 279 | 280 | ************************************************************************ 281 | * * 282 | * 7. Limitation of Liability * 283 | * -------------------------- * 284 | * * 285 | * Under no circumstances and under no legal theory, whether tort * 286 | * (including negligence), contract, or otherwise, shall any * 287 | * Contributor, or anyone who distributes Covered Software as * 288 | * permitted above, be liable to You for any direct, indirect, * 289 | * special, incidental, or consequential damages of any character * 290 | * including, without limitation, damages for lost profits, loss of * 291 | * goodwill, work stoppage, computer failure or malfunction, or any * 292 | * and all other commercial damages or losses, even if such party * 293 | * shall have been informed of the possibility of such damages. This * 294 | * limitation of liability shall not apply to liability for death or * 295 | * personal injury resulting from such party's negligence to the * 296 | * extent applicable law prohibits such limitation. Some * 297 | * jurisdictions do not allow the exclusion or limitation of * 298 | * incidental or consequential damages, so this exclusion and * 299 | * limitation may not apply to You. * 300 | * * 301 | ************************************************************************ 302 | 303 | 8. Litigation 304 | ------------- 305 | 306 | Any litigation relating to this License may be brought only in the 307 | courts of a jurisdiction where the defendant maintains its principal 308 | place of business and such litigation shall be governed by laws of that 309 | jurisdiction, without reference to its conflict-of-law provisions. 310 | Nothing in this Section shall prevent a party's ability to bring 311 | cross-claims or counter-claims. 312 | 313 | 9. Miscellaneous 314 | ---------------- 315 | 316 | This License represents the complete agreement concerning the subject 317 | matter hereof. If any provision of this License is held to be 318 | unenforceable, such provision shall be reformed only to the extent 319 | necessary to make it enforceable. Any law or regulation which provides 320 | that the language of a contract shall be construed against the drafter 321 | shall not be used to construe this License against a Contributor. 322 | 323 | 10. Versions of the License 324 | --------------------------- 325 | 326 | 10.1. New Versions 327 | 328 | Mozilla Foundation is the license steward. Except as provided in Section 329 | 10.3, no one other than the license steward has the right to modify or 330 | publish new versions of this License. Each version will be given a 331 | distinguishing version number. 332 | 333 | 10.2. Effect of New Versions 334 | 335 | You may distribute the Covered Software under the terms of the version 336 | of the License under which You originally received the Covered Software, 337 | or under the terms of any subsequent version published by the license 338 | steward. 339 | 340 | 10.3. Modified Versions 341 | 342 | If you create software not governed by this License, and you want to 343 | create a new license for such software, you may create and use a 344 | modified version of this License if you rename the license and remove 345 | any references to the name of the license steward (except to note that 346 | such modified license differs from this License). 347 | 348 | 10.4. Distributing Source Code Form that is Incompatible With Secondary 349 | Licenses 350 | 351 | If You choose to distribute Source Code Form that is Incompatible With 352 | Secondary Licenses under the terms of this version of the License, the 353 | notice described in Exhibit B of this License must be attached. 354 | 355 | Exhibit A - Source Code Form License Notice 356 | ------------------------------------------- 357 | 358 | This Source Code Form is subject to the terms of the Mozilla Public 359 | License, v. 2.0. If a copy of the MPL was not distributed with this 360 | file, You can obtain one at http://mozilla.org/MPL/2.0/. 361 | 362 | If it is not possible or desirable to put the notice in a particular 363 | file, then You may include the notice in a location (such as a LICENSE 364 | file in a relevant directory) where a recipient would be likely to look 365 | for such a notice. 366 | 367 | You may add additional accurate notices of copyright ownership. 368 | 369 | Exhibit B - "Incompatible With Secondary Licenses" Notice 370 | --------------------------------------------------------- 371 | 372 | This Source Code Form is "Incompatible With Secondary Licenses", as 373 | defined by the Mozilla Public License, v. 2.0. 374 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 |

2 | 3 |

4 | Rust Design Patterns 5 |

6 |

7 | 8 | ## Creational Patterns 9 | 10 | | Pattern | Description | Status | 11 | |:-------:|:----------- |:------:| 12 | | [Factory Method](/creational/factory.rs) | Defers instantiation of an object to a specialized function for creating instances | ✔ | 13 | | [Abstract Factory](/creational/abstract_factory.rs) | Provides an interface for creating families of releated objects | ✔ | 14 | | [Builder](/creational/builder.rs) | Builds a complex object using simple objects | ✔ | 15 | | [Singleton](/creational/singleton.rs) | Restricts instantiation of a type to one object | ✔ | 16 | 17 | 18 | ## Behavioral Patterns 19 | | Pattern | Description | Status | 20 | |:-------:|:----------- |:------:| 21 | | [Strategy](/behavioral/strategy.rs) | Enables an algorithm's behavior to be selected at runtime | ✔ | 22 | | [State](/behavioral/state.rs) | Encapsulates varying behavior for the same object based on its internal state | ✔ | 23 | | [Command](/behavioral/command.rs) | Converts requests or simple operations into objects. | ✔ | 24 | | [Iterator](/behavioral/iterator.rs) | Lets you traverse elements of a collection without exposing its underlying representation | ✔ | 25 | | [Observer](/behavioral/observer.rs) | Allows one objects to notify other objects about changes in their state. | ✔ | 26 | | [Chain of Responsibility](/behavioral/chain_of_responsibility.rs) | Avoids coupling a sender to receiver by giving more than object a chance to handle the request | ✔ | 27 | 28 | 29 | 30 | 31 | ## Structural Patterns 32 | 33 | | Pattern | Description | Status | 34 | |:-------:|:----------- |:------:| 35 | | [Adapter](/structural/adapter.rs) | allows objects with incompatible interfaces to collaborate. | ✔ | 36 | | [Decorator](/structural/decorator.rs) | Adds behavior to an object, statically or dynamically | ✔ | 37 | | [Proxy](/structural/proxy.rs) | Provides a surrogate for an object to control it's actions | ✔ | 38 | 39 | -------------------------------------------------------------------------------- /behavioral/chain_of_responsibility.rs: -------------------------------------------------------------------------------- 1 | //! Chain of Responsibility is a behavioral design pattern that lets you pass requests along a chain of handlers. 2 | //! Upon receiving a request, each handler decides either to process the request or to pass it to the next handler in the chain. 3 | 4 | // The Handler trait declares a method for building the chain of 5 | // handlers. It also declares a method for executing a request. 6 | trait Handler<'a> { 7 | fn set_next(&mut self, next: &'a dyn Handler<'a>) -> &mut dyn Handler<'a>; 8 | fn handle(&self, request: &str); 9 | } 10 | 11 | struct AHandler<'a> { 12 | name: String, 13 | next: Option<&'a dyn Handler<'a>>, 14 | } 15 | impl<'a> AHandler<'a> { 16 | fn new(name: String) -> AHandler<'a> { 17 | AHandler { name, next: None } 18 | } 19 | } 20 | impl<'a> Handler<'a> for AHandler<'a> { 21 | fn set_next(&mut self, next: &'a dyn Handler<'a>) -> &mut dyn Handler<'a> { 22 | self.next = Some(next); 23 | self 24 | } 25 | fn handle(&self, request: &str) { 26 | println!("{} handle the request: {}", self.name, request); 27 | if let Some(v) = &self.next { 28 | v.handle(request); 29 | } 30 | } 31 | } 32 | 33 | struct BHandler<'a> { 34 | next: Option<&'a dyn Handler<'a>>, 35 | } 36 | impl<'a> BHandler<'a> { 37 | fn new() -> BHandler<'a> { 38 | BHandler { next: None } 39 | } 40 | } 41 | impl<'a> Handler<'a> for BHandler<'a> { 42 | fn set_next(&mut self, next: &'a dyn Handler<'a>) -> &mut dyn Handler<'a> { 43 | self.next = Some(next); 44 | self 45 | } 46 | fn handle(&self, request: &str) { 47 | println!("BHandler handle the request: {}", request); 48 | if let Some(v) = &self.next { 49 | v.handle(request); 50 | } 51 | } 52 | } 53 | 54 | struct Client; 55 | impl<'a> Client { 56 | fn handle>(h: &T) { 57 | h.handle("do something...") 58 | } 59 | } 60 | 61 | fn main() { 62 | let a1 = AHandler::new("dog".to_string()); 63 | Client::handle(&a1); 64 | 65 | println!(); 66 | let mut b = BHandler::new(); 67 | let mut a2 = AHandler::new("cat".to_string()); 68 | b.set_next(&a1); 69 | // or 70 | // let h = b.set_next(&a1); 71 | //a2.set_next(h); 72 | a2.set_next(&b); 73 | Client::handle(&a2); 74 | } 75 | -------------------------------------------------------------------------------- /behavioral/command.rs: -------------------------------------------------------------------------------- 1 | //! Each action is encapsulated into a struct with the trait Command 2 | 3 | use std::collections::HashMap; 4 | 5 | trait Command { 6 | fn execute(&self); 7 | } 8 | 9 | #[derive(Copy, Clone)] 10 | struct TV; 11 | impl TV { 12 | fn new() -> TV { 13 | TV 14 | } 15 | fn on(&self) { 16 | println!("TV is on, watch movies."); 17 | } 18 | fn off(&self) { 19 | println!("TV is off"); 20 | } 21 | } 22 | 23 | struct TVOnCommand { 24 | tv: TV, 25 | } 26 | 27 | impl TVOnCommand { 28 | fn new(tv: TV) -> TVOnCommand { 29 | TVOnCommand { tv } 30 | } 31 | } 32 | 33 | impl Command for TVOnCommand { 34 | fn execute(&self) { 35 | self.tv.on(); 36 | } 37 | } 38 | 39 | struct TVOffCommand { 40 | tv: TV, 41 | } 42 | 43 | impl TVOffCommand { 44 | fn new(tv: TV) -> TVOffCommand { 45 | TVOffCommand { tv } 46 | } 47 | } 48 | 49 | impl Command for TVOffCommand { 50 | fn execute(&self) { 51 | self.tv.off(); 52 | } 53 | } 54 | 55 | struct TVRemoteControl { 56 | commands: HashMap>, 57 | } 58 | 59 | impl TVRemoteControl { 60 | fn new() -> TVRemoteControl { 61 | TVRemoteControl { 62 | commands: HashMap::new(), 63 | } 64 | } 65 | fn set_command(&mut self, idx: i32, cmd: Box) { 66 | self.commands.insert(idx, cmd); 67 | } 68 | fn press_button(&self, idx: i32) { 69 | if let Some(cmd) = self.commands.get(&idx) { 70 | cmd.execute(); 71 | } else { 72 | println!("do nothing."); 73 | } 74 | } 75 | } 76 | 77 | fn main() { 78 | let tv = TV::new(); 79 | let mut remote_control = TVRemoteControl::new(); 80 | remote_control.press_button(0); 81 | 82 | remote_control.set_command(1, Box::new(TVOnCommand::new(tv))); 83 | remote_control.set_command(2, Box::new(TVOffCommand::new(tv))); 84 | 85 | remote_control.press_button(1); 86 | remote_control.press_button(2); 87 | } 88 | -------------------------------------------------------------------------------- /behavioral/iterator.rs: -------------------------------------------------------------------------------- 1 | //! Iterator is a behavioral design pattern that lets you traverse elements of a collection without exposing its underlying representation (list, stack, tree, etc.). 2 | 3 | trait Iterator { 4 | fn next(&mut self) -> Option; 5 | fn current(&self) -> Option; 6 | fn has_next(&self) -> bool; 7 | fn reset(&mut self); 8 | } 9 | 10 | struct Container { 11 | data: Vec, 12 | } 13 | 14 | struct ConcreteIterator<'a, T> { 15 | idx: usize, 16 | container: &'a Container, 17 | } 18 | 19 | impl<'a, T: Clone> ConcreteIterator<'a, T> { 20 | fn new(container: &'a Container) -> ConcreteIterator { 21 | ConcreteIterator { idx: 0, container } 22 | } 23 | } 24 | 25 | impl<'a, T: Clone> Iterator for ConcreteIterator<'a, T> { 26 | fn next(&mut self) -> Option { 27 | let item = self.container.data.get(self.idx).cloned(); 28 | self.idx += 1; 29 | item 30 | } 31 | fn current(&self) -> Option { 32 | self.container.data.get(self.idx).cloned() 33 | } 34 | fn has_next(&self) -> bool { 35 | self.container.data.len() > self.idx 36 | } 37 | fn reset(&mut self) { 38 | self.idx = 0; 39 | } 40 | } 41 | 42 | impl Container { 43 | fn new() -> Container { 44 | Container { data: Vec::new() } 45 | } 46 | fn add_item(&mut self, item: T) { 47 | self.data.push(item); 48 | } 49 | fn iter(&self) -> impl Iterator + '_ { 50 | ConcreteIterator::new(self) 51 | } 52 | } 53 | 54 | fn main() { 55 | let mut c = Container::new(); 56 | c.add_item(1); 57 | c.add_item(2); 58 | c.add_item(3); 59 | 60 | let mut iter = c.iter(); 61 | let has_next = iter.has_next(); 62 | assert_eq!(has_next, true); 63 | let item = iter.next(); 64 | println!("item: {:?}", item); 65 | iter.reset(); 66 | while iter.has_next() { 67 | let v = iter.next().unwrap(); 68 | println!("item: {}", v); 69 | } 70 | let item = iter.next(); 71 | assert_eq!(item, None); 72 | } 73 | -------------------------------------------------------------------------------- /behavioral/observer.rs: -------------------------------------------------------------------------------- 1 | //! Observer is a behavioral design pattern that allows one objects to notify other objects about changes in their state. 2 | 3 | trait IObserver { 4 | fn update(&self); 5 | } 6 | 7 | trait ISubject<'a, T: IObserver> { 8 | fn attach(&mut self, observer: &'a T); 9 | fn detach(&mut self, observer: &'a T); 10 | fn notify_observers(&self); 11 | } 12 | 13 | struct Subject<'a, T: IObserver> { 14 | observers: Vec<&'a T>, 15 | } 16 | impl<'a, T: IObserver + PartialEq> Subject<'a, T> { 17 | fn new() -> Subject<'a, T> { 18 | Subject { 19 | observers: Vec::new(), 20 | } 21 | } 22 | } 23 | 24 | impl<'a, T: IObserver + PartialEq> ISubject<'a, T> for Subject<'a, T> { 25 | fn attach(&mut self, observer: &'a T) { 26 | self.observers.push(observer); 27 | } 28 | fn detach(&mut self, observer: &'a T) { 29 | if let Some(idx) = self.observers.iter().position(|x| *x == observer) { 30 | self.observers.remove(idx); 31 | } 32 | } 33 | fn notify_observers(&self) { 34 | for item in self.observers.iter() { 35 | item.update(); 36 | } 37 | } 38 | } 39 | 40 | #[derive(PartialEq)] 41 | struct ConcreteObserver { 42 | id: i32, 43 | } 44 | impl IObserver for ConcreteObserver { 45 | fn update(&self) { 46 | println!("Observer id:{} received event!", self.id); 47 | } 48 | } 49 | 50 | fn main() { 51 | let mut subject = Subject::new(); 52 | let observer_a = ConcreteObserver { id: 1 }; 53 | let observer_b = ConcreteObserver { id: 2 }; 54 | 55 | subject.attach(&observer_a); 56 | subject.attach(&observer_b); 57 | subject.notify_observers(); 58 | 59 | subject.detach(&observer_b); 60 | subject.notify_observers(); 61 | } 62 | -------------------------------------------------------------------------------- /behavioral/state.rs: -------------------------------------------------------------------------------- 1 | //! State is a behavioral design pattern that lets an object alter its behavior when its internal state changes. 2 | //! It appears as if the object changed its class. 3 | 4 | //! We’ll implement a blog post workflow 5 | //! 1. A blog post starts as an empty draft. 6 | //! 2. When the draft is done, a review of the post is requested. 7 | //! 3. When the post is approved, it gets published. 8 | //! 4. Only published blog posts return content to print, so unapproved posts can’t accidentally be published. 9 | 10 | trait State { 11 | fn request_review(self: Box) -> Box; 12 | fn approve(self: Box) -> Box; 13 | fn content<'a>(&self, _post: &'a Post) -> &'a str { 14 | "" 15 | } 16 | } 17 | 18 | struct Draft; 19 | impl State for Draft { 20 | fn request_review(self: Box) -> Box { 21 | Box::new(PendingReview {}) 22 | } 23 | fn approve(self: Box) -> Box { 24 | self 25 | } 26 | } 27 | 28 | struct PendingReview; 29 | impl State for PendingReview { 30 | fn request_review(self: Box) -> Box { 31 | self 32 | } 33 | fn approve(self: Box) -> Box { 34 | Box::new(Published {}) 35 | } 36 | } 37 | 38 | struct Published; 39 | impl State for Published { 40 | fn request_review(self: Box) -> Box { 41 | self 42 | } 43 | fn approve(self: Box) -> Box { 44 | self 45 | } 46 | fn content<'a>(&self, post: &'a Post) -> &'a str { 47 | &post.content 48 | } 49 | } 50 | 51 | struct Post { 52 | state: Option>, 53 | content: String, 54 | } 55 | 56 | impl Post { 57 | fn new() -> Post { 58 | Post { 59 | state: Some(Box::new(Draft {})), 60 | content: String::new(), 61 | } 62 | } 63 | fn add_text(&mut self, text: &str) { 64 | self.content.push_str(text); 65 | } 66 | fn content(&self) -> &str { 67 | self.state.as_ref().unwrap().content(self) 68 | } 69 | fn request_review(&mut self) { 70 | if let Some(s) = self.state.take() { 71 | self.state = Some(s.request_review()) 72 | } 73 | } 74 | fn approve(&mut self) { 75 | if let Some(s) = self.state.take() { 76 | self.state = Some(s.approve()) 77 | } 78 | } 79 | } 80 | 81 | fn main() { 82 | let mut post = Post::new(); 83 | 84 | let text = "State is a behavioral design pattern."; 85 | post.add_text(text); 86 | assert_eq!("", post.content()); 87 | 88 | post.request_review(); 89 | assert_eq!("", post.content()); 90 | 91 | post.approve(); 92 | assert_eq!(text, post.content()); 93 | println!("post content: {}", post.content()); 94 | } 95 | -------------------------------------------------------------------------------- /behavioral/strategy.rs: -------------------------------------------------------------------------------- 1 | trait FlyBehaviour { 2 | fn fly(&self); 3 | } 4 | 5 | struct FlyWithWings; 6 | 7 | impl FlyBehaviour for FlyWithWings { 8 | fn fly(&self) { 9 | println!("i can fly!") 10 | } 11 | } 12 | 13 | struct FlyNoWay; 14 | 15 | impl FlyBehaviour for FlyNoWay { 16 | fn fly(&self) { 17 | println!("i can't fly!~~") 18 | } 19 | } 20 | 21 | trait Duck { 22 | fn get_fly_behaviour(&self) -> &dyn FlyBehaviour; 23 | fn fly(&self) { 24 | let s = self.get_fly_behaviour(); 25 | s.fly(); 26 | } 27 | } 28 | 29 | struct MallardDuck { 30 | fly_behaviour: Box, 31 | } 32 | 33 | impl Duck for MallardDuck { 34 | fn get_fly_behaviour(&self) -> &dyn FlyBehaviour { 35 | return &(*self.fly_behaviour); 36 | } 37 | } 38 | 39 | impl MallardDuck { 40 | fn new(fly_behaviour: Box) -> Self { 41 | MallardDuck { fly_behaviour } 42 | } 43 | fn set_fly_behaviour(&mut self, fly_behaviour: Box) { 44 | self.fly_behaviour = fly_behaviour; 45 | } 46 | } 47 | 48 | struct ModelDuck { 49 | fly_behaviour: Box, 50 | } 51 | 52 | impl Duck for ModelDuck { 53 | fn get_fly_behaviour(&self) -> &dyn FlyBehaviour { 54 | return &(*self.fly_behaviour); 55 | } 56 | } 57 | 58 | impl ModelDuck { 59 | fn new(fly_behaviour: Box) -> Self { 60 | ModelDuck { fly_behaviour } 61 | } 62 | } 63 | 64 | pub fn main() { 65 | let mut mallard_duck = MallardDuck::new(Box::new(FlyWithWings)); 66 | mallard_duck.fly(); 67 | mallard_duck.set_fly_behaviour(Box::new(FlyNoWay)); 68 | mallard_duck.fly(); 69 | 70 | let model_duck = ModelDuck::new(Box::new(FlyNoWay)); 71 | model_duck.fly(); 72 | } 73 | -------------------------------------------------------------------------------- /creational/abstract_factory.rs: -------------------------------------------------------------------------------- 1 | //! Abstract Factory is a creational design pattern that lets you produce families of related objects without specifying their concrete classes. 2 | 3 | trait GUIFactory { 4 | fn create_button(&self) -> Box; 5 | fn create_checkbox(&self) -> Box; 6 | } 7 | 8 | struct WinFactory; 9 | impl GUIFactory for WinFactory { 10 | fn create_button(&self) -> Box { 11 | Box::new(WinButton {}) 12 | } 13 | fn create_checkbox(&self) -> Box { 14 | Box::new(WinCheckbox {}) 15 | } 16 | } 17 | 18 | struct MacFactory; 19 | impl GUIFactory for MacFactory { 20 | fn create_button(&self) -> Box { 21 | Box::new(MacButton {}) 22 | } 23 | fn create_checkbox(&self) -> Box { 24 | Box::new(MacCheckbox {}) 25 | } 26 | } 27 | 28 | trait Button { 29 | fn paint(&self); 30 | } 31 | 32 | struct WinButton; 33 | impl Button for WinButton { 34 | fn paint(&self) { 35 | println!("windows os button"); 36 | } 37 | } 38 | 39 | struct MacButton; 40 | impl Button for MacButton { 41 | fn paint(&self) { 42 | println!("mac os button"); 43 | } 44 | } 45 | 46 | trait Checkbox { 47 | fn paint(&self); 48 | } 49 | 50 | struct WinCheckbox; 51 | impl Checkbox for WinCheckbox { 52 | fn paint(&self) { 53 | println!("windows os checkbox"); 54 | } 55 | } 56 | 57 | struct MacCheckbox; 58 | impl Checkbox for MacCheckbox { 59 | fn paint(&self) { 60 | println!("mac os checkbox"); 61 | } 62 | } 63 | 64 | struct Application; 65 | impl Application { 66 | fn new_gui_factory(os: &str) -> Box { 67 | match os { 68 | "mac" => Box::new(MacFactory {}), 69 | "win" => Box::new(WinFactory {}), 70 | _ => panic!("error"), 71 | } 72 | } 73 | } 74 | 75 | fn main() { 76 | let mac_app = Application::new_gui_factory("mac"); 77 | let btn = mac_app.create_button(); 78 | btn.paint(); // output: mac os button 79 | let cb = mac_app.create_checkbox(); 80 | cb.paint(); // output: mac os checkbox 81 | 82 | let win_app = Application::new_gui_factory("win"); 83 | let btn = win_app.create_button(); 84 | btn.paint(); // output: windows os button 85 | let cb = win_app.create_checkbox(); 86 | cb.paint(); // output: windows os checkbox 87 | } 88 | -------------------------------------------------------------------------------- /creational/builder.rs: -------------------------------------------------------------------------------- 1 | //! Builder is a creational design pattern, which allows constructing complex objects step by step. 2 | 3 | #[derive(Clone)] 4 | struct Product { 5 | parts: Vec, 6 | } 7 | 8 | impl Product { 9 | fn new() -> Product { 10 | Product { parts: Vec::new() } 11 | } 12 | fn list_parts(&self) { 13 | let parts_list = String::from(" parts "); 14 | println!("{0}{1}{0}", "*".repeat(10), parts_list); 15 | for v in &self.parts { 16 | println!("{}", v); 17 | } 18 | println!("{0}{1}{0}", "*".repeat(10), "*".repeat(parts_list.len())); 19 | } 20 | } 21 | 22 | /** 23 | * The Builder trait specifies methods for creating the different parts of 24 | * the Product objects. 25 | */ 26 | trait Builder { 27 | fn produce_part_a(&mut self); 28 | fn produce_part_b(&mut self); 29 | fn produce_part_c(&mut self); 30 | fn get_product(&mut self) -> Product; 31 | } 32 | 33 | /** 34 | * The Concrete Builder classes follow the Builder interface and provide 35 | * specific implementations of the building steps. Your program may have several 36 | * variations of Builders, implemented differently. 37 | */ 38 | struct ContreteBuilder1 { 39 | product: Product, 40 | } 41 | 42 | impl ContreteBuilder1 { 43 | fn new() -> ContreteBuilder1 { 44 | ContreteBuilder1 { 45 | product: Product::new(), 46 | } 47 | } 48 | } 49 | 50 | impl Builder for ContreteBuilder1 { 51 | fn produce_part_a(&mut self) { 52 | self.product.parts.push("part a1".to_string()); 53 | } 54 | fn produce_part_b(&mut self) { 55 | self.product.parts.push("part b1".to_string()); 56 | } 57 | fn produce_part_c(&mut self) { 58 | self.product.parts.push("part c1".to_string()); 59 | } 60 | fn get_product(&mut self) -> Product { 61 | let p = self.product.clone(); 62 | self.product = Product::new(); 63 | p 64 | } 65 | } 66 | 67 | struct ContreteBuilder2 { 68 | product: Product, 69 | } 70 | 71 | impl ContreteBuilder2 { 72 | fn new() -> ContreteBuilder2 { 73 | ContreteBuilder2 { 74 | product: Product::new(), 75 | } 76 | } 77 | } 78 | 79 | impl Builder for ContreteBuilder2 { 80 | fn produce_part_a(&mut self) { 81 | self.product.parts.push("part a ~~~~ 2".to_string()); 82 | } 83 | fn produce_part_b(&mut self) { 84 | self.product.parts.push("part b ~~~~ 2".to_string()); 85 | } 86 | fn produce_part_c(&mut self) { 87 | self.product.parts.push("part c ~~~~ 2".to_string()); 88 | } 89 | fn get_product(&mut self) -> Product { 90 | let p = Product { 91 | parts: self.product.parts.clone(), 92 | ..self.product 93 | }; 94 | self.product = Product::new(); 95 | p 96 | } 97 | } 98 | 99 | /** 100 | * The Director is only responsible for executing the building steps in a 101 | * particular sequence. It is helpful when producing products according to a 102 | * specific order or configuration. Strictly speaking, the Director class is 103 | * optional, since the client can control builders directly. 104 | */ 105 | struct Director { 106 | builder: Box, 107 | } 108 | 109 | impl Director { 110 | fn new(builder: Box) -> Director { 111 | Director { builder: builder } 112 | } 113 | 114 | fn construct(&mut self) { 115 | self.builder.produce_part_a(); 116 | self.builder.produce_part_b(); 117 | self.builder.produce_part_c(); 118 | } 119 | } 120 | 121 | fn main() { 122 | let builder1 = Box::new(ContreteBuilder1::new()); 123 | let mut direct = Director::new(builder1); 124 | direct.construct(); 125 | let product = direct.builder.get_product(); 126 | product.list_parts(); 127 | // output: 128 | /* 129 | ********** parts ********** 130 | part a1 131 | part b1 132 | part c1 133 | *************************** 134 | */ 135 | 136 | let build2 = Box::new(ContreteBuilder2::new()); 137 | let mut direct = Director::new(build2); 138 | direct.construct(); 139 | let product = direct.builder.get_product(); 140 | product.list_parts(); 141 | // output: 142 | /* 143 | ********** parts ********** 144 | part a ~~~~ 2 145 | part b ~~~~ 2 146 | part c ~~~~ 2 147 | *************************** 148 | */ 149 | } 150 | -------------------------------------------------------------------------------- /creational/factory.rs: -------------------------------------------------------------------------------- 1 | //! Factory method creational design pattern allows creating objects without having to specify the exact type of the object that will be created. 2 | 3 | trait Shape { 4 | fn draw(&self); 5 | } 6 | 7 | enum ShapeType { 8 | Rectangle, 9 | Circle, 10 | } 11 | 12 | struct Rectangle {} 13 | 14 | impl Shape for Rectangle { 15 | fn draw(&self) { 16 | println!("draw a rectangle!"); 17 | } 18 | } 19 | 20 | struct Circle {} 21 | 22 | impl Shape for Circle { 23 | fn draw(&self) { 24 | println!("draw a circle!"); 25 | } 26 | } 27 | 28 | struct ShapeFactory; 29 | impl ShapeFactory { 30 | fn new_shape(s: &ShapeType) -> Box { 31 | match s { 32 | ShapeType::Circle => Box::new(Circle {}), 33 | ShapeType::Rectangle => Box::new(Rectangle {}), 34 | } 35 | } 36 | } 37 | 38 | fn main() { 39 | let shape = ShapeFactory::new_shape(&ShapeType::Circle); 40 | shape.draw(); // output: draw a circle! 41 | 42 | let shape = ShapeFactory::new_shape(&ShapeType::Rectangle); 43 | shape.draw(); // output: draw a rectangle! 44 | } 45 | -------------------------------------------------------------------------------- /creational/singleton.rs: -------------------------------------------------------------------------------- 1 | use std::mem::MaybeUninit; 2 | use std::sync::{Mutex, Once}; 3 | 4 | #[derive(Debug)] 5 | struct Config { 6 | db_connection_str: String, 7 | } 8 | 9 | fn get_config() -> &'static Mutex { 10 | static mut CONF: MaybeUninit> = MaybeUninit::uninit(); 11 | static ONCE: Once = Once::new(); 12 | 13 | ONCE.call_once(|| unsafe { 14 | CONF.as_mut_ptr().write(Mutex::new(Config { 15 | db_connection_str: "test config".to_string(), 16 | })); 17 | }); 18 | 19 | unsafe { &*CONF.as_ptr() } 20 | } 21 | 22 | fn main() { 23 | let f1 = get_config(); 24 | println!("{:?}", f1); 25 | // modify 26 | { 27 | let mut conf = f1.lock().unwrap(); 28 | conf.db_connection_str = "hello".to_string(); 29 | } 30 | 31 | let f2 = get_config(); 32 | println!("{:?}", f2); 33 | let conf2 = f2.lock().unwrap(); 34 | 35 | assert_eq!(conf2.db_connection_str, "hello".to_string()) 36 | } 37 | -------------------------------------------------------------------------------- /rust-logo.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/lpxxn/rust-design-pattern/d020c4641af0b272a7984fdacb45af0827dfac57/rust-logo.png -------------------------------------------------------------------------------- /structural/adapter.rs: -------------------------------------------------------------------------------- 1 | use std::rc::Rc; 2 | 3 | // The Target defines the domain-specific interface used by the client code. 4 | trait Target { 5 | fn get_request(&self) -> String { 6 | String::from("Target: The default target's behavior.") 7 | } 8 | } 9 | 10 | struct DefaultTarget; 11 | impl Target for DefaultTarget {} 12 | 13 | // The Adaptee contains some useful behavior, but its interface is 14 | // incompatible with the existing client code. The Adaptee needs some 15 | // adaptation before the client code can use it. 16 | struct Adaptee { 17 | req_str: String, 18 | } 19 | 20 | impl Adaptee { 21 | fn new(s: String) -> Adaptee { 22 | Adaptee { req_str: s } 23 | } 24 | fn specific_request(&self) -> String { 25 | format!("specific request: {}", self.req_str) 26 | } 27 | } 28 | 29 | // The Adapter makes the Adaptee's interface compatible with the Target's 30 | // interface. 31 | struct Adapter { 32 | adaptee: Rc, 33 | } 34 | 35 | impl Adapter { 36 | fn new(a: Rc) -> Adapter { 37 | Adapter { adaptee: a } 38 | } 39 | } 40 | 41 | impl Target for Adapter { 42 | fn get_request(&self) -> String { 43 | format!("Adapter: {}", self.adaptee.specific_request()) 44 | } 45 | } 46 | 47 | // The client code supports all classes that follow the Target trait. 48 | struct Client; 49 | impl Client { 50 | fn client_code(target: &T) { 51 | println!("{}", target.get_request()); 52 | } 53 | } 54 | 55 | fn main() { 56 | println!("Client: I can work just fine with the Target objects:"); 57 | Client::client_code(&DefaultTarget {}); 58 | let adaptee = Rc::new(Adaptee::new("hello world".to_string())); 59 | println!("Client: The Adaptee class has a weird interface. See, I don't understand it:"); 60 | println!("Adaptee: {}", adaptee.specific_request()); 61 | 62 | println!("Client: But I can work with it via the Adapter:"); 63 | let adapter = Adapter::new(adaptee); 64 | Client::client_code(&adapter); 65 | } 66 | -------------------------------------------------------------------------------- /structural/decorator.rs: -------------------------------------------------------------------------------- 1 | use std::rc::Rc; 2 | 3 | // The base Component trait defines operations that can be altered by 4 | // decorators. 5 | trait Component { 6 | fn operation(&self) -> String; 7 | } 8 | 9 | // Concrete Components provide default implementations of the operations. 10 | // There might be several variations of these classes. 11 | struct ConcreteComponent {} 12 | 13 | impl Component for ConcreteComponent { 14 | fn operation(&self) -> String { 15 | "ConcreteComponent".to_string() 16 | } 17 | } 18 | 19 | // The base Decorator class follows the same interface as the other 20 | // components. The primary purpose of this class is to define the wrapping 21 | // interface for all concrete decorators. The default implementation of the 22 | // wrapping code might include a field for storing a wrapped component and 23 | // the means to initialize it. 24 | trait Decorator: Component { 25 | fn new(component: Rc) -> Self; 26 | } 27 | 28 | // Concrete Decorators call the wrapped object and alter its result in some 29 | // way. 30 | struct ConcreteDecoratorA { 31 | component: Rc, 32 | } 33 | 34 | impl Decorator for ConcreteDecoratorA { 35 | fn new(component: Rc) -> Self { 36 | ConcreteDecoratorA { component } 37 | } 38 | } 39 | 40 | impl Component for ConcreteDecoratorA { 41 | fn operation(&self) -> String { 42 | format!("ConcreteDecoratorA: {}", self.component.operation()) 43 | } 44 | } 45 | 46 | struct ConcreteDecoratorB { 47 | component: Rc, 48 | } 49 | 50 | impl Decorator for ConcreteDecoratorB { 51 | fn new(component: Rc) -> Self { 52 | ConcreteDecoratorB { component } 53 | } 54 | } 55 | 56 | impl Component for ConcreteDecoratorB { 57 | fn operation(&self) -> String { 58 | format!("ConcreteDecoratorB: {}", self.component.operation()) 59 | } 60 | } 61 | 62 | // The client code works with all objects using the Component interface. 63 | // This way it can stay independent of the concrete classes of 64 | // components it works with. 65 | struct Client; 66 | 67 | impl Client { 68 | fn client_code(component: &T) { 69 | println!("result: {}", component.operation()) 70 | } 71 | } 72 | 73 | fn main() { 74 | let component = Rc::new(ConcreteComponent {}); 75 | println!("client: i get a simple component: "); 76 | Client::client_code(component.as_ref()); 77 | println!("client: now I've got a decorated component:"); 78 | let decorator_a1 = ConcreteDecoratorA::new(component.clone()); 79 | Client::client_code(&decorator_a1); 80 | 81 | let decorator_a2 = ConcreteDecoratorB::new(Rc::new(decorator_a1)); 82 | Client::client_code(&decorator_a2); 83 | } 84 | -------------------------------------------------------------------------------- /structural/proxy.rs: -------------------------------------------------------------------------------- 1 | //! Proxy is a structural design pattern that lets you provide a substitute or placeholder for another object. 2 | //! A proxy controls access to the original object, allowing you to perform something either before or after the request gets through to the original object. 3 | 4 | // The Subject trait declares common operations for both RealSubject and 5 | // the Proxy. As long as the client works with RealSubject using this 6 | // interface, you'll be able to pass it a proxy instead of a real subject. 7 | trait Subject { 8 | fn request(&self); 9 | } 10 | 11 | // The RealSubject contains some core business logic. Usually, RealSubjects 12 | // are capable of doing some useful work which may also be very slow or 13 | // sensitive - e.g. correcting input data. A Proxy can solve these issues 14 | // without any changes to the RealSubject's code. 15 | struct RealSubject {} 16 | impl Subject for RealSubject { 17 | fn request(&self) { 18 | println!("RealSubject: handling request."); 19 | } 20 | } 21 | 22 | struct Proxy<'a> { 23 | real_subject: &'a RealSubject, 24 | } 25 | impl<'a> Proxy<'a> { 26 | fn new(real_subject: &'a RealSubject) -> Proxy { 27 | Proxy { real_subject } 28 | } 29 | fn check_access(&self) -> bool { 30 | // Some real checks should go here. 31 | println!("Proxy: checking access prior to firing a real request."); 32 | true 33 | } 34 | fn log_access(&self) { 35 | println!("Proxy: logging the request."); 36 | } 37 | } 38 | 39 | impl<'a> Subject for Proxy<'a> { 40 | // The most common applications of the Proxy pattern are lazy loading, 41 | // caching, controlling the access, logging, etc. A Proxy can perform one of 42 | // these things and then, depending on the result, pass the execution to the 43 | // same method in a linked RealSubject object. 44 | fn request(&self) { 45 | if self.check_access() { 46 | self.real_subject.request(); 47 | self.log_access(); 48 | } 49 | } 50 | } 51 | 52 | struct Client; 53 | impl Client { 54 | // The client code is supposed to work with all objects (both subjects 55 | // and proxies) via the Subject interface in order to support both real 56 | // subjects and proxies. In real life, however, clients mostly work with 57 | // their real subjects directly. In this case, to implement the pattern 58 | // more easily, you can extend your proxy from the real subject's class. 59 | fn client_code(subject: &T) { 60 | subject.request(); 61 | } 62 | } 63 | 64 | fn main() { 65 | let real_subject = RealSubject {}; 66 | println!("client: executing the client code with a real subject:"); 67 | Client::client_code(&real_subject); 68 | 69 | println!(""); 70 | println!("client: executing the same client code with a proxy:"); 71 | let proxy = Proxy::new(&real_subject); 72 | Client::client_code(&proxy); 73 | } 74 | --------------------------------------------------------------------------------