Java怎样实现菱形继承

Java怎样实现菱形继承

首先要有个表示People行为的接口：
public interface PeopleBehavior {
void sayName();
}

则有People类实现如下：

public class People implements PeopleBehavior {
private final String mName;

public People(final String name) {
mName = name;
}

@Override
public void sayName() {
System.out.println("People:" + "sayName:" + mName);
}
}

为了模拟C++的虚继承两边指向同一个虚基类对象，参考Decorator pattern的设计，关键在于要有一个People类的wrapper：

public class PeopleWrapper implements PeopleBehavior {
private final People mPeople;

public PeopleWrapper(final People people) {
mPeople = people;
}

@Override
public void sayName() {
mPeople.sayName();
}
}

表示Programmer行为的接口：
public interface ProgramBehavior {
void setLanguage(final String lanaguage);
void program();
}

则有Programmer类：

public class Programmer extends PeopleWrapper implements ProgramBehavior {
private String mLanguage;

public Programmer(final People people) {
super(people);
}

@Override
public void program() {
System.out.println("Programmer:" + "program:" + mLanguage);
}

@Override
public void setLanguage(final String lanaguage) {
mLanguage = lanaguage;
}
}

同理表示Manager行为的接口：
public interface ManagerBehavior {
void setStyle(final String style);
void manage();
}

Manager类：

public class Manager extends PeopleWrapper implements ManagerBehavior {
private String mStyle;

public Manager(final People people) {
super(people);
}

@Override
public void setStyle(final String style) {
mStyle = style;
}

@Override
public void manage() {
System.out.println("Manager:" + "manage:" + mStyle);
}
}

如此，不难得出ProgramManager类的设计：

public class ProgramManager extends PeopleWrapper implements ProgramBehavior,
ManagerBehavior {

private final ProgramBehavior mProgramAbility;
private final ManagerBehavior mManagerAbility;

public ProgramManager(final People people) {
super(people);
mProgramAbility = new Programmer(people);
mManagerAbility = new Manager(people);
}

@Override
public void setStyle(final String style) {
mManagerAbility.setStyle(style);
}

@Override
public void manage() {
mManagerAbility.manage();
}

@Override
public void setLanguage(final String lanaguage) {
mProgramAbility.setLanguage(lanaguage);
}

@Override
public void program() {
mProgramAbility.program();
}
}

public static void main(string[]args){ string s1=joptionpane.showinputdialog("请输入★单数★行"); int n=integer.parseint(s1); for(int i=1;i<=(n+1)/2;i++){ for(int j=1;j<=(n+1)/2-i;j++){system.out.print(" ");} for(int k=1;k<=2*i-1;k++){system.out.print("*");} system.out.println(); } for(int i=1;i<=(n-1)/2;i++){ for(int j=1;j<=i;j++){system.out.print(" ");} for(int k=1;k<=n-2*i;k++){system.out.print("*");} system.out.println(); } } ???????的地方应该是 k<=n-2*i 下面的第i行有 n-2*i个 * 号 第2个问题没有看懂