1.第三题
package net.mindview.interfaces; abstract class Base{ public Base(){ print(); } abstract void print(); } public class Test3 extends Base{ private int i = 5; @Override void print() { System.out.println(i); } public static void main(String[] args) { Test3 t = new Test3(); t.print(); } }
输出结果:
0 5
调用基类构造方法的时候, 只是给子类的成员变量分配了一块内存空间, 并将内存空间的值设置为默认值0. 当真正调用子类构造方法之前才会为成员变量赋值.
2.第七题
package net.mindview.interfaces; //啮(nie四声)齿动物 interface Rodent{ void say(); } //老鼠 class Mouse implements Rodent{ public void say(){System.out.println("hi,我是 Mouse");} } //鼹鼠 class Gerbil implements Rodent{ public void say(){System.out.println("hi,我是 Gerbil");} } //大颊鼠 class Hamster implements Rodent{ public void say(){System.out.println("hi,我是 Hamster");} } public class RodentHome { public static void instroduce(Rodent rodent){ rodent.say(); } public static void instroduceAll(Rodent[] rodents){ for(Rodent r: rodents){ instroduce(r); } } public static void main(String[] args) { Rodent[] rodents = { new Mouse(), new Gerbil(), new Hamster() }; instroduceAll(rodents); } }
3.第八题
package net.mindview.interfaces; import java.util.Random; /** 定义一个乐器类 */ interface Instrucment { int value = 5; //定义在接口中的成员是static&final的 void play(Note n); void adjust(); } /**抽象类*/ abstract class PublicMethod implements Instrucment{ public abstract void play(Note n); //这个方法不用谢,以为继承自Object的类都有toString()方法 //public abstract String toString(); public abstract void adjust(); } /**定义n个子类*/ class Wind extends PublicMethod { public void play(Note n){ System.out.println("Wind.play() " + n);} public String toString(){ return "Wind.what()";} public void adjust(){ System.out.println("Wind.adjust()");} } class Purcussion extends PublicMethod{ public void play(Note n){ System.out.println("Purcussion.play() " + n);} public String toString(){ return "Purcussion.what()";} public void adjust(){ System.out.println("Purcussion.adjust()");} } class Stringed extends PublicMethod{ public void play(Note n){ System.out.println("Stringed.play() " + n);} public String toString(){ return "Stringed.what()";} public void adjust(){ System.out.println("Stringed.adjust()");} } class Brass extends Wind{ public void play(Note n){ System.out.println("Brass.play() " + n);} public void adjust(){ System.out.println("Brass.adjust()");} } class WoodWind extends Wind{ public void play(Note n){ System.out.println("WoodWind.play() " + n);} public String toString(){ return "WoodWind.what()";} } class Other extends Wind{ public void play(Note n){ System.out.println("Other.play() " + n);} public String toString(){ return "Other.what()";} } /** 定义一个随机乐器生成器 */ class RandomInstrucmentGenerator { Random rand = new Random(100); public Instrucment next(){ switch(rand.nextInt(6)){ default: case 0: return new Wind(); case 1: return new Purcussion(); case 2: return new Stringed(); case 3: return new Brass(); case 4: return new WoodWind(); case 5: return new Other(); } } } public class Music5 { public static void tune(Instrucment i){ i.play(Note.MIDDLE_C); i.toString(); } public static void tuneAll(Instrucment[] e){ for(Instrucment i : e){ tune(i); } } private static RandomInstrucmentGenerator gen = new RandomInstrucmentGenerator(); public static void main(String[] args) { /*Instrucment[] orchestra = { new Wind(), new Purcussion(), new Stringed(), new Brass(), new WoodWind(), new Other() };*/ Instrucment[] ins = new Instrucment[10]; for(int i=0; i<ins.length; i++){ ins[i] = Music5.gen.next(); } tuneAll(ins); } }
4.练习11--这个练习是巩固如何写适配器设计模式
package net.mindview.interfaces; /** * 字符串反转类 */ public class StringReverse { public String name(){ return getClass().getSimpleName(); } //反转 public String reverse(String s) { char[] array = s.toCharArray(); String reverse = ""; for (int i = array.length - 1; i >= 0; i--) { reverse += array[i]; } return reverse; } }
package net.mindview.interfaces; public class StringReverseAdapter implements Processor{ StringReverse stringReverse; public StringReverseAdapter(StringReverse stringReverse){ this.stringReverse = stringReverse; } @Override public String name() { // TODO Auto-generated method stub return stringReverse.name(); } @Override public Object process(Object input) { // TODO Auto-generated method stub return stringReverse.reverse((String)input); } }
在使用的时候,可以直接调用Apply的process方法
public static void main(String[] args) { Apply.process(new StringReverseAdapter(new StringReverse()), "i am lily"); }
Apply方法没有写出来,这个类实在课文内部定义的,可以参考http://www.cnblogs.com/ITPower/p/8550627.html中第二点:解耦的案例一,案例二和案例三. 其中Apply类定义在案例一中。
5.第十二题
package net.mindview.interfaces; interface CanFight { void fight(); } interface CanSwim { void swim(); } interface CanFly { void fly(); } interface CanClimb { void climb(); } //行为特征 class ActionCharacter { public void fight(){ } } class Hero extends ActionCharacter implements CanFight,CanSwim,CanFly,CanClimb{ @Override public void fly() { } @Override public void swim() { } @Override public void climb() { } } //冒险 public class Adventure { public static void f(CanFly fly){ fly.fly(); } public static void s(CanSwim swim){ swim.swim(); } public static void v(CanFight fight){ fight.fight(); } public static void m(ActionCharacter ac){ ac.fight(); } public static void p(CanClimb c){ c.climb(); } public static void main(String[] args) { Hero hero = new Hero(); f(hero); s(hero); v(hero); m(hero); p(hero); } }
6.第十四题：这道题的思想和书上p180页的案例思想一样.继承+多次实现接口
package net.mindview.interfaces; interface BaseInterface1 { public void a(); public void b(); } interface BaseInterface2 { public void c(); public void d(); } interface BaseInterface3 { public void e(); public void f(); } interface Interface4 extends BaseInterface1,BaseInterface2,BaseInterface3{ public void g(); } class Specific implements Interface4{ public void h(){ } @Override public void a() { } @Override public void b() { } @Override public void c() { } @Override public void d() { } @Override public void e() { } @Override public void f() { } @Override public void g() { } } public class Test14 extends Specific implements Interface4{ public static void aa(BaseInterface1 b1){ b1.a(); b1.b(); } public static void bb(BaseInterface2 b){ b.c(); b.d(); } public static void cc(BaseInterface3 b){ b.e(); b.f(); } public static void dd(Interface4 b){ b.g(); } public static void main(String[] args) { Specific specific = new Specific(); aa(specific); bb(specific); cc(specific); dd(specific); } }
7.第十六题
package net.mindview.interfaces; import java.io.IOException; import java.nio.CharBuffer; import java.util.Random; import java.util.Scanner; class RandomChar { Random rand = new Random(47); Random count = new Random(47); private static final char[] captials = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray(); public char[] make(){ StringBuffer sb = new StringBuffer(""); for(int i=0; i<count.nextInt(10); i++){ sb.append(captials[rand.nextInt(captials.length)]); } return sb.toString().toCharArray(); } public static void main(String[] args) { RandomChar rc = new RandomChar(); char[] c = rc.make(); System.out.println(c); for(char ch:c){ System.out.print(ch); } } } public class AdapterRandomChar implements Readable{ RandomChar rc; private int count; public AdapterRandomChar(RandomChar rc, int count){ this.rc = rc; this.count = count; } @Override public int read(CharBuffer cb) throws IOException { if(count-- == 0){ return -1; } StringBuffer sb = new StringBuffer(""); for(char c:rc.make()){ sb.append(c); } String result = sb.toString() + " " ; cb.append(result); return result.length(); } public static void main(String[] args) { Scanner s = new Scanner(new AdapterRandomChar(new RandomChar(), 5)); while(s.hasNext()){ System.out.print(s.next()+" "); } } }
8.第十八题
package net.mindview.interfaces; //产品 interface Cycle { } class Unicycle implements Cycle{ public Unicycle(){ System.out.println("我是一个Unicycle"); } } class Bicycle implements Cycle{ public Bicycle(){ System.out.println("我是一个Bicycle"); } } class Tricycle implements Cycle{ public Tricycle(){ System.out.println("我是一个Tricycle"); } } //工厂类 interface CycleFactory{ public Cycle make(); } class UnicycleFactory implements CycleFactory{ @Override public Cycle make() { return new Unicycle(); } } class BicycleFactory implements CycleFactory{ @Override public Cycle make() { return new Bicycle(); } } class TricycleFactory implements CycleFactory{ @Override public Cycle make() { return new Tricycle(); } } public class CycleCustomer { public static Cycle serviceCustoemr(CycleFactory fact){ return fact.make(); } public static void main(String[] args) { Cycle u = serviceCustoemr(new UnicycleFactory()); Cycle b = serviceCustoemr(new BicycleFactory()); Cycle t = serviceCustoemr(new TricycleFactory()); } }
9.第十九题
package net.mindview.interfaces; import java.util.Random; /** * 这时一个抛硬币和掷骰子等类型的框架 */ interface ThrowProduct {} class ThrowCorn implements ThrowProduct{ Random rand = new Random(47); public ThrowCorn(){ if(rand.nextInt(100) %2 ==0){ System.out.println("硬币的正面"); }else{ System.out.println("硬币的反面"); } } } class ThrowDice implements ThrowProduct{ Random rand = new Random(47); public ThrowDice(){ System.out.println("掷的骰子数是"+rand.nextInt(7)); } } interface ThrowFactory{ ThrowProduct throwOut(); } class ThrowCornFactory implements ThrowFactory{ public ThrowCornFactory(){ System.out.print("开始抛硬币:"); } @Override public ThrowProduct throwOut() { return new ThrowCorn(); } } class ThrowDiceFactory implements ThrowFactory{ public ThrowDiceFactory(){ System.out.print("开始掷骰子:"); } @Override public ThrowProduct throwOut() { return new ThrowDice(); } } public class ThrowFrame { public static ThrowProduct service(ThrowFactory f){ return f.throwOut(); } public static void main(String[] args) { service(new ThrowCornFactory()); service(new ThrowDiceFactory()); } }
结果:
开始抛硬币:硬币的正面 开始掷骰子:掷的骰子数是6
