第9次作业--接口及接口回调

题目描述

利用接口和接口回调，实现简单工厂模式，当输入不同的字符，代表相应图形时，利用工厂类获得图形对象，再计算以该图形为底的柱体体积。

源代码

Shape 接口

package com.tomotoes.probleam.nine;

public interface Shape {
    double getArea();
}

工厂类

package com.tomotoes.probleam.nine;

import com.tomotoes.probleam.nine.shapes.*;

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.function.Supplier;

public class Factory {
    private static Scanner scanner = new Scanner(System.in);

    private static double input() {
        return scanner.nextDouble();
    }

    private static Map> factory = new HashMap<>();

    static {
        factory.put("rect", () -> new Rect(input(), input()));
        factory.put("circle", () -> new Circle(input()));
        factory.put("square", () -> new Square(input()));
        factory.put("trapezoid", () -> new Trapezoid(input(), input(), input()));
        factory.put("triangle", () -> new Triangle(input(), input(), input()));
    }

    public static Shape getInstance(String type) {
        return factory.getOrDefault(type, () -> null).get();
    }
}

主类

package com.tomotoes.probleam.nine;

import com.tomotoes.probleam.nine.shapes.Column;

import java.util.Objects;
import java.util.Scanner;

public class App {
    private static Scanner scanner = new Scanner(System.in);

    public static void init() {
        System.out.println("矩形类:   输入 rect -> Rect(宽,长)");
        System.out.println("圆形类:   输入 circle -> Circle(半径)");
        System.out.println("三角形类: 输入 triangle -> Triangle(底边,高,斜边)");
        System.out.println("正方形类: 输入 square -> Square(边长)");
        System.out.println("梯形类: 输入 trapezoid -> Trapezoid(顶边,底边,高)");
        System.out.printf("输入其他值, 程序退出.\n\n");
    }

    public static void main(String[] args) {
        init();
        while (true) {
            System.out.println("请输入类型参数: ");
            final String input = scanner.next().trim().toLowerCase();

            System.out.println("请输入类所需的构造参数: ");
            Shape shape = Factory.getInstance(input);

            if (Objects.isNull(shape)) {
                System.out.println("程序退出.");
                return;
            }

            System.out.println("请输入柱体的高: ");
            final double height = scanner.nextDouble();

            Column column = new Column(height, shape);
            System.out.printf("柱体的体积为: " + column.getVolume() + "\n\n");
        }

    }
}

柱体类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Column {
    double height;
    Shape shape;

    public Column(double height, Shape shape) {
        this.height = height;
        this.shape = shape;
    }

    public double getVolume() {
        return height * shape.getArea();
    }
}

矩形类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Rect implements Shape {
    double width;
    double length;

    public Rect(double width, double length) {
        this.width = width;
        this.length = length;
    }

    @Override
    public double getArea() {
        return width * length;
    }
}

圆形类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Circle implements Shape {
    double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return Math.pow(radius, 2) * Math.PI;
    }
}

正方形类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Square implements Shape {
    double length;

    public Square(double length) {
        this.length = length;
    }

    @Override
    public double getArea() {
        return length * length;
    }
}

梯形类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Trapezoid implements Shape {
    double top;
    double base;
    double height;

    public Trapezoid(double top, double base, double height) {
        this.top = top;
        this.base = base;
        this.height = height;
    }

    @Override
    public double getArea() {
        return (top + base) * height * 2;
    }
}

三角形类

package com.tomotoes.probleam.nine.shapes;

import com.tomotoes.probleam.nine.Shape;

public class Triangle implements Shape {
    double base;
    double height;
    double oblique;

    public Triangle(double base, double height, double oblique) {
        this.base = base;
        this.height = height;
        this.oblique = oblique;
    }

    @Override
    public double getArea() {
        return base * height / 2;
    }
}

运行截图