9.3完全解耦（适配器设计模式）下

Processor 接口↓↓↓

Processor 与 Filter 有相同的行为,所以可以用适配器包装

public interface Processor {
    String name();
    Object process(Object input);
}

Filter 类↓↓↓

Processor 与 Filter 有相同的行为,所以可以用适配器包装

public class Filter {
    public String name() {
        return getClass().getSimpleName();
    }

    public Waveform process(Waveform input) {return input;}
}

FilterAdapter 适配器↓↓↓

适配器FilterAdapter 实现接口Processor

public class FilterAdapter implements Processor {

    Filter filter;

    public FilterAdapter(Filter filter) {
        this.filter = filter;
    }


    @Override
    public String name() {
        return filter.name();
    }

    @Override
    public Object process(Object input) {
        return filter.process((Waveform) input);
    }
}

HighPass 类↓↓↓

public class HighPass extends Filter {

    double cutoff;

    public HighPass(double cutoff) {this.cutoff = cutoff;}

    public Waveform process(Waveform input) {
        System.out.println("cutoff ----> " + cutoff);
        return input;
    }

}

FilterProcessor类↓↓↓

main函数在此
FilterAdapter适配器类将HighPass包装了一下
FilterAdapter是一个Processor
HighPass是一个Filter
Apply.process()接受的是Processor

public class FilterProcessor {
    public static void main(String[] args) {
        Waveform w = new Waveform();
        Apply.process(new FilterAdapter(new LowPass(1.0)), w);
        Apply.process(new FilterAdapter(new HighPass(2.0)), w);//看下面的Apply.process
        Apply.process(new FilterAdapter(new BandPass(3.0,4.0)), w);
    }
}

Apply.process

public class Apply {
    public static void process(Processor p, Object s) {
        System.out.println("Using Processor ----> " + p.name());
        System.out.println(p.process(s));//这里打印了 Waveform
    }
}