Java部分类

Java不支持部分或开放类。其他JVM语言是,但不是Java。在您的示例中,最简单的事情可能是不幸地使用委派。您可以让aimpl使用另一个对象来实现这些扩展方法的接口。然后,生成的aimpl将生成迭代器方法等方法,这些方法可以委托给您传入的用户创建的对象。

How about that: 
Compute.java  =    your class
Compute$.java  =   base class for partial classes. Reference a Compute object
Compute$Add.java = your partial class. Subclass Compute$.
Compute$Sub.java = your partial class. Subclass Compute$.

文件compute.java

public class Compute {
    protected int a, b;
    Compute$Add add;
    Compute$Sub sub;

    public Compute() {
        add = new Compute$Add(this);
        sub = new Compute$Sub(this);
    }

    public int[] doMaths() {
        int radd = add.add();
        int rsub = sub.sub();
        return new int[] { radd, rsub };
    }
}

文件计算$JAVA

public abstract class Compute$ {
    protected Compute $that;
    public Compute$(Compute c){
        $that=c;
    }
}

文件compute$add.java

public class Compute$Add extends Compute$ {
    public Compute$Add(Compute c) {
        super(c);
        // TODO Auto-generated constructor stub
    }

    public int add(){
        return $that.a+$that.b;
    }
}

文件compute$sub.java

public class Compute$Sub extends Compute$ {
    public Compute$Sub(Compute c) {
        super(c);
    }

    public int sub() {
        return $that.a - $that.b;
    }
}

你可以扩展a(比如接口b扩展a),扩展aimpl和实现b(类bimpl扩展aimpl实现b)。