HuoJingping-优快云博客

原创《JAVA编程思想》学习备忘:Holding Your Objects-1

Its a farily simple program that only has a fixed quantity of objects with known lifetimes.Generics and type-safe containers泛型与类型安全容器One of the problems of using pre-Java SE5 containers was tha

2008-11-11 22:17:00 685

原创《JAVA编程思想》学习备忘（p345 Inner Classes-3)

续《JAVA编程思想》学习备忘（p345 Inner Classes-2)Closures & callbacksA closure is a callable oject that retains information from the scope in which it was created.The closure provided by the inner class is

2008-08-27 17:19:00 732

原创《JAVA编程思想》学习备忘（p345 Inner Classes-2)

续《JAVA编程思想》学习备忘（p345 Inner Classes-1)Factory Method revisitedLook at how much nicer the interfaces/Factories.java example comes out when you use anonymous inner classes:interface Service { void

2008-08-27 11:13:00 693

原创《JAVA编程思想》学习备忘（p345 Inner Classes-1)

Its possible to place a class definition within another class definition.This is called an inner class.The inner class is a valuable feature because it allows you to group classes that logically

2008-08-25 22:55:00 770

原创《JAVA编程思想》学习备忘（第311页Interfaces-1)

Interfaces and abstract classes provide a more structured way to separate interface from implementation.抽象类是普通类和接口的中继,它是构建一个含有些许未实现方法的类的重要和必须的工具。你不能总是使用一个纯粹的接口。Abstract classes and methods当你需要通过

2008-08-03 18:03:00 496

原创《JAVA编程思想》学习备忘（第277页Polymorphism-3)

续《JAVA编程思想》学习备忘（第277页Polymorphism-2)Behavior of polymorphic methods inside constructors示例:class Glyph { void draw(){ System.out.println("Glyph.draw()"); } Glyph(){ System.out.println("Glyph(

2008-07-26 23:51:00 482

原创《JAVA编程思想》学习备忘（第277页Polymorphism-2)

续《JAVA编程思想》学习备忘（第277页Polymorphism-1)Pitfall:"overriding" private methods以下这个例子是重写了私有的方法吗?public class PrivateOverride { private void f(){ System.out.println("private f()"); } public static vo

2008-07-23 20:15:00 573

原创《JAVA编程思想》学习备忘（第277页Polymorphism-1)

Polymorphism多态Upcasting revisited 示例:public enum Note { MIDDLE_C, C_SHARP, B_FLAT;}class Instrument { public void play(Note n){ System.out.println("Instrument.play()"); }}public class

2008-07-23 00:12:00 697

原创续《JAVA编程思想》学习备忘（第237页：Reusing Classes）-5

The final keywordJava 中 final 关键字表示不可被改变，无外乎两个理由：定制或者效率。但这两个理由很不同，它很可能造成不当使用final关键字。以下分别讨论三个final关键字可被使用的地方：data,methods 和 classes.final data许多编程语言都有一个方法来告诉编译器某块数据是“常量”。有两个理由说明一个常量非常有用：1、它可做为一个编译时从不改

2008-07-21 23:17:00 625

原创《JAVA编程思想》学习备忘（第237页：Reusing Classes）-5

续《JAVA编程思想》学习备忘（第237页：Reusing Classes）-4protectedNow that youve been introduced to inheritance,the keyword protected finally has meaning,In an ideal world,the private keyword would be enough.In r

2008-02-21 22:41:00 560

原创《JAVA编程思想》学习备忘（第237页：Reusing Classes）-4

续《JAVA编程思想》学习备忘（第237页：Reusing Classes）-3Name hidingIf a Java base class has a method name thats overloaded several times,redefining that method name in the derived class will not hide any of the

2008-02-19 00:28:00 683

原创《JAVA编程思想》学习备忘（第237页：Reusing Classes）-3

续《JAVA编程思想》学习备忘（第237页：Reusing Classes）-2Combining composition and inheritanceIt is very common to use composition and inheritance together.The following example shows the creation of a more comple

2008-02-16 10:16:00 689

原创《JAVA编程思想》学习备忘（第237页：Reusing Classes）-2

续《JAVA编程思想》学习备忘（第237页：Reusing Classes）-1 Initializing the base class...its essential that the base-class subobject be initialized correctly,and theres only one way to guarantee this:Perform the

2008-02-13 19:03:00 659

原创《JAVA编程思想》学习备忘（第237页：Reusing Classes）-1

One of the most compelling features about Java is code reuse.But to be revolutionary,youve got to be able to do a lot more than copy code and change it. Composition syntax重写toString()方法的例子：//

2008-02-12 22:58:00 615

原创《JAVA编程思想》学习备忘（第209页：Access Control）-3

续《JAVA编程思想》学习备忘（第209页：Access Control）-2Interface and implementationAccess control is often referred to as implementation hiding.Wrapping data and methods within classes in combination with implem

2008-02-12 14:56:00 748

原创《JAVA编程思想》学习备忘（第209页：Access Control）-2

续《JAVA编程思想》学习备忘（第209页：Access Control）-1Using imports to change behaviorA feature that is missing from Java is Cs conditional compilation,which allows you to change a switch and get different beha

2008-02-11 21:59:00 823

原创《JAVA编程思想》学习备忘（第209页：Access Control）-1

Access control(or implementation hiding) is about"not getting it right the first time."存取控制： All good writers-including those who write software-know that a piece of work isnt good until its bee

2008-02-10 10:13:00 797

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-7

续《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-6Variable argument lists自从所有的类最终继承于根类Object，你可以创建一个带有Object数组的方法，并且这样调用：例1：//:initialization/VarArgs.java//Using array syntax to create variable ar

2008-02-01 22:02:00 725

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-6

续《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-5Non-static instance initializationJava 提供一种相似的语法，叫做实例初始化，用来为每个对象初始化非静态变量。举例：//:initialization/Mugs.java// Java "Instance Initialization."i

2008-02-01 19:08:00 687

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-5

续《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-4Member initialization如果一个类中的属性为原始数据类型，它将会确保有一个初始值。以下程序为一例证：import static staticPrint.Print.print;public class InitialValues{ boolean t;

2008-01-28 18:01:00 649

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-4

续《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-3The meaning of static静态的含义With the this keyword in mind,you can more fully understand what it means to make a method static.It means that there

2008-01-08 22:15:00 637

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-3

续《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）-2Calling constructors from constructorsWhen you write several constuctors for a class,there are times when youd like to call one constructor from

2008-01-01 22:06:00 570

原创《JAVA编程思想》学习备忘（第155页：Initialization & Cleanup）--2

The this keywordThe this keyword-which can be used only inside a non-static method-produces the reference to the object that the method has been called for.但调用同处一类中的方法时不需要this 。The this keywo

2007-12-21 00:11:00 631

原创《JAVA编程思想》学习备忘（第135页：Controlling Execution）

Controlling Execution Like a sentient creature,a program must manipulate its world and make choices during execution.In Java you make choices with execution control statements. 像一个有感知的生物体，一个程序在其

2007-12-16 13:06:00 709

原创《JAVA编程思想》学习备忘（第93页：Operators--3）

续《JAVA编程思想》学习备忘（第93页：Operators--2）Common pitfalls when using operators运算符使用中的“陷井”一个Java中的错误例子：while(x=y){ //...}当x和y是boolean类型是，x=y是一个合法的表达式，能通过编译，如果y的值为true,则此例会产生一个死循环。 Casting

2007-12-14 20:30:00 585

原创《JAVA编程思想》学习备忘（第93页：Operators--2）

续《JAVA编程思想》学习备忘（第93页：Operators--1）Short-circuiting 使用逻辑运算符时的“短路”现象：在并列逻辑判断项运算过程中得到的值如可明确为最终结果，其后的逻辑运算将不执行。举个例子：import static staticPrint.Print.print;public class ShortCircuit{ stati

2007-12-13 23:55:00 818

原创《JAVA编程思想》学习备忘（第93页：Operators--1）

在最底层，数据在Java中靠运算符来控制。Simpler print statements 以下为简化了的打印语句包及方法,使用时可导入包:| package staticPrint;| public class Print { | public static void print(Object obj){| System.out.pr

2007-12-12 22:19:00 581

原创《JAVA编程思想》学习备忘（p61：Everything Is an Object--3）

（接Everything Is an Object--2）Methods,arguments,and return valuesMethods in Java determine the message an object can receive.The fundamental parts of a method are the name,the arguments,the return

2007-12-11 23:01:00 673

原创《JAVA编程思想》学习备忘（第61页：Everything Is an Object--2）

(接Everything Is an Object--1）You never need to destroy an object 本小节介绍Java中的垃圾清理工作。Scoping 范围（作用域），在Java中用一对花括号来表示：{}举例：| { int x = 12; //x 的作用范围 { int q

2007-12-10 20:22:00 640

原创《JAVA编程思想》学习备忘（第61页：Everything Is an Object--1）

“If we spoke a different language,we would perceive a somewhat different world” 此为本章开篇引言，大意：如果我们使用另类的语言，我们将追寻一个些许不同的世界。很多人认为编程语言对于初学者来说大都晦涩难懂，但不要忘掉的是，它仅仅是一门语言，既然是语言，就如同我们日常所说所讲的语言一样

2007-12-09 23:33:00 1084

HuoJingping的专栏