重构 : 改善既有代码的设计

chapter 1 refactoring， a first example（新增批注共21条）

the starting point

the first step in refactoring

decomposing and redistributing the statement method

replacing the conditional logic on price code with polymorphism

final thoughts

chapter 2 principles in refactoring（新增批注共11条）

defining refactoring

why should you refactor？

when should you refactor？

what do i tell my manager？

problems with refactoring

refactoring and design

refactoring and performance

where did refactoring come from？

chapter 3 bad smells in code （by kent beck and martin fowler）

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duplicated code

long method

large class

.long parameter list

divergent change

shotgun surgery

feature envy

data clumps

primitive obsession

switch statements

parallel inheritance hierarchies

lazy class

speculative generality

temporary field

message chains

middle man

inappropriate intimacy

alternative classes with different interfaces

incomplete library class

data class

refused bequest

comments

chapter 4 building tests（新增批注共2条）

the value of self．testing code

the junit testing framework

adding more tests

chapter 5 toward a catalog of refactorings

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format of the refactorings

finding references

how mature are these refactorings？

chapter 6 composing methods（新增批注共9条）

extract method

inline method

inline temp

replace temp with query

introduce explaining variable

split temporary variable

remove assignments to parameters

replace method with method object

substitute algorithm

chapter 7 moving features between objects

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move method

move field

extract class

inline class

hide delegate

remove middle man

introduce foreign method

introduce local extension

chapter 8 organizing data（新增批注共9条）

self encapsulate field

replace data value with object

change value to reference

change reference to value

replace array with object

duplicate observed data

change unidirectional association to bidirectional

change bidirectional association to unidirectional

replace magic number with symbolic constant

encapsulate field

encapsulate collection

replace record with data class

replace type code with class

replace type code with subclasses

replace type code with state/strategy

replace subclass with fields

chapter 9 simplifying conditional expressions

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decompose conditional

consolidate conditional expression

consolidate duplicate conditional fragments

remove contr01 flag

replace nested conditional with guard clauses

replace conditional with polymorphism

introduce null object

introduce assertion

chapter 10 making method calls simpler（新增批注共14条）

rename method

add parameter

remove parameter

separate query from modifier

parameterize method

replace parameter with explicit methods

preserve whole object

replace parameter with method

introduce parameter object

remove setting method

hide method

replace constructor with factory method

encapsulate downcast

replace error code with exception

replace exception with test

chapter 11 dealing with generalization（新增批注共6条）

pull up field

pull up method

pull up constructor body

push down method

push down field

extract subclass

extract superclass

extract interface

collapse hierarchy

form template method

replace inheritance with delegation

replace delegation with inheritance

chapter 12 big refactorings （by kent beck and martin fowler）

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tease apart inheritance

convert procedural design to objects

separate domain from presentation

extract hierarchy

chapter 13 refactoring， reuse， and reality （by william opdyke）

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a reality check

why are developers reluctant to refactor their programs？

a reality check （revisited）

resources and references for refactoring

implications regarding software reuse and technology transfer

a final note

references

chapter 14 refactoring tools （by don roberts and john brant）

refactoring with a tool

technical criteria for a refactoring tool

practical criteria for a refactoring tool

wrap up

chapter 15 putting it all together （by kent beck）

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references

list of soundbites

index

重构，一言以蔽之，就是在不改变外部行为的前提下，有条不紊地改善代码。多年前，正是本书原版的出版，使重构终于从编程高手们的小圈子走出，成为众多普通程序员日常开发工作中不可或缺的一部分。《重构：改善既有代码的设计（评注版）》也因此成为与《设计模式》齐名的经典著作，被译为中、德、俄、日等众多语言，在世界范围内畅销不衰。

　　Martin Fowler等著的《重构：改善既有代码的设计（评注版）》凝聚了软件开发社区专家多年摸索而获得的宝贵经验，拥有不因时光流逝而磨灭的价值。今天，无论是重构本身，业界对重构的理解，还是开发工具对重构的支持力度，都与本书最初出版时不可同日而语，但书中所蕴涵的意味和精华，依然值得反复咀嚼，而且往往能够常读常新。

　　《重构：改善既有代码的设计（评注版）》力邀国内资深专家执笔，在英文原著基础上增加中文点评与注释，旨在以先行者的学研心得与实践感悟，对读者阅读与学习加以点拨、指明捷径。

MartinFowler和本书另几位作者清楚揭示了重构过程，他们为面向对象软件开发所做的贡献难以衡量。《重构——改善既有代码的设计(评注版)》解释了重构的原理和最佳实践，并指出何时何地你应该开始挖掘你的代码以求改善。本书的核心是一系列完整的重构方法，其中每一项都介绍一种经过实践检验的代码变换手法的动机和技术。某些项目如ExtractMethod和MoveField看起来可能很浅显，但不要掉以轻心，因为理解这类技术正是有条不紊地进行重构的关键。本书所提的这些重构手法将帮助你一次一小步地修改你的代码，这就减少了过程中的风险。很快你就会把这些重构手法和其名称加入自己的开发词典中，并且朗朗上口。