设计模式/结构型设计模式
简述
使用不同的标准来过滤一组对象，通过逻辑运算以解耦的方式把它们连接起来
结合多个标准来获得单一标准
UML图
代码
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@Slf4j
@Getter
public class OrangeCat extends Cat {
private String color;
public OrangeCat(String color) {
this.color = color;
}
@Override
public void run() {
log.debug(“橘猫 run — >> “);
}
}
@Slf4j
@Getter
public class BlueCat extends Cat {
private String color;
public BlueCat(String color) {
this.color = color;
}
@Override
public void run() {
log.debug(“蓝猫 run — >> “);
}
}
public interface CatFilter {
List<Cat> filter(List<Cat> list);
}
public class DefaultCatFilter implements CatFilter {
@Override
public List<Cat> filter(List<Cat> list) {
List<Cat> orange = new ArrayList<>();
list.stream().map(cat -> {
if (cat instanceof OrangeCat) {
orange.add(cat);
}
return orange;
}).collect(Collectors.toList());
return orange;
}
}
public class ColorFilter implements CatFilter {
@Override
public List<Cat> filter(List<Cat> list) {
List<Cat> color = new ArrayList<>();
list.stream().map(cat -> {
if (((OrangeCat) cat).getColor().equals("橘色")) {
color.add(cat);
}
return color;
}).collect(Collectors.toList());
return color;
}
}
public class Client {
public static void main(String[] args) {
OrangeCat orange1 = new OrangeCat(“橘色”);
OrangeCat orange2 = new OrangeCat(“橘色”);
OrangeCat orange3 = new OrangeCat(“橘白相间”);
BlueCat blue1 = new BlueCat("蓝色");
BlueCat blue2 = new BlueCat("蓝黑色”);
List < Cat > list = new ArrayList<>();
list.add(orange1);
list.add(orange2);
list.add(orange3);
list.add(blue1);
list.add(blue2);
List<Cat> filter = new DefaultCatFilter().filter(list);
List<Cat> color = new ColorFilter().filter(filter);
color.forEach(Cat::run);
}
}
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