设计模式：可复用面向对象软件的基础 ([美] Erich Gamma)（Z-Library）

【One-Line Pitch】 A field-defining catalog of 23 reusable object-oriented design patterns, showing not just what each pattern looks like but when to apply it and what trade-offs it buys you. Best for developers and students who already know an OO language (C++ or Smalltalk) and want to design systems that survive change. 【Book Arc】 - **Opening (~0%–10%)**: Frames what a design pattern is, using Smalltalk MVC as the running example, and explains the two-axis catalog (purpose × scope) that organizes all 23 patterns. - **Early (~10%–22%)**: Walks through the design problems patterns solve — finding objects, deciding granularity, programming to interfaces rather than implementations, and anticipating change — then introduces the running case study: a document editor (Lexi). - **Early–Middle (~22%–35%)**: Covers the creational patterns (Abstract Factory, Builder, Factory Method, Prototype, Singleton), each with intent, structure, participants, collaborations, and effects. - **Middle (~35%–55%)**: Moves into structural patterns (Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy), emphasizing how objects are composed and how abstraction is separated from implementation. - **Late (~55%–85%)**: Treats behavioral patterns (Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor), focused on interaction and responsibility assignment. - **Ending (~85%–100%)**: Wraps up with how patterns relate to one another and how to select and apply them in practice; the excerpts do not cover the closing chapters in detail. 【Key Takeaways】 - **Patterns are named solutions to recurring design problems**, not code to copy (Opening): each entry documents intent, applicability, structure, participants, and consequences so you can judge fit before implementing. - **The catalog is organized by purpose and scope** (Opening): creational / structural / behavioral crossed with class-level vs. object-level, which makes the 23 patterns navigable rather than a flat list. - **Program to an interface, not an implementation** (Early): the book's recurring theme — declaring variables against abstract types reduces coupling and enables the substitution patterns rely on. - **Design for change** (Early): patterns exist to let one aspect of a system vary independently; the book maps common causes of redesign to the patterns that absorb them. - **Creational patterns decouple clients from concrete classes** (Early–Middle): Abstract Factory, Factory Method, Builder, Prototype, and Singleton each hide instantiation in a different way, trading flexibility against complexity. - **Structural patterns manage composition and wrapping** (Middle): Adapter converts interfaces, Bridge separates abstraction from implementation, Composite builds recursive trees, Decorator adds responsibilities dynamically, Facade simplifies subsystems, Flyweight shares state, Proxy controls access. - **Behavioral patterns assign responsibility and control interaction** (Late): Command encapsulates requests (enabling undo/redo), Iterator abstracts traversal, Observer decouples model from views, Strategy and State vary algorithm or state, Visitor adds operations without changing element classes. - **Patterns interact and overlap** (Late): the book stresses relationships among patterns and warns that choosing one often implies trade-offs elsewhere — selection is a design decision, not a lookup. 【Reading Tips】 - Read Chapter 1 carefully; it defines the vocabulary and the selection method that every later pattern entry assumes. - Use the case study (document editor) as a thread — it reappears across patterns and shows how they combine in one realistic system. - For each pattern, skim the sample code on first pass but deep-read the intent, applicability, and consequences sections; those are what you'll actually reuse. - Treat the pattern catalog as a reference, not a novel — jump to entries as design problems arise, and revisit the relationships discussion at the end. - If you're new to OO design, read with a language you know (C++ or Smalltalk) open beside you to test the structures mentally. 【Coverage Limits】 This guide is based on stratified excerpts covering roughly the first half of the book plus scattered later material; the closing chapters and several behavioral pattern details are only partially represented, so specifics there are inferred from the catalog structure rather than fully verified.