Halo semuanya, nama saya Konstantin. Saya berkembang di Jawa di Tinkoff.ru dan cinta SOLID. Dalam artikel ini, kami akan merumuskan prinsip substitusi Lisk, menunjukkan hubungannya dengan prinsip Terbuka-Tertutup, mempelajari cara membentuk hierarki warisan dengan benar, dan menjawab pertanyaan filosofis apakah persegi adalah persegi panjang.

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void drawShape(Shape shape) {
   if (shape instanceof Square) {
       drawSquare((Square) shape);
   } else {
       drawCircle((Circle) shape);
   }
}

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public class Rectangle {
    private int width;
    private int height;

    public int getWidth() {
        return width;
    }

    public void setWidth(int width) {
        this.width = width;
    }

    public int getHeight() {
        return height;
    }

    public void setHeight(int height) {
        this.height = height;
    }

    public int perimeter() {
        return 2 * height + 2 * width;
    }
}

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    @Override
    public void setWidth(int width) {
        super.setWidth(width);
        super.setHeight(width);
    }

    @Override
    public void setHeight(int height) {
        super.setHeight(height);
        super.setWidth(height);
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public class RectangleTest {

    @Test
    public void perimeter() {
        Rectangle rectangle = new Rectangle();
        rectangle.setHeight(5);
        rectangle.setWidth(7);

        int result = rectangle.perimeter();

        assertEquals(24, result);
    }

} 

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public class RectangleTest {

    @Test
    public void perimeter() {
        Rectangle rectangle = initRectangle();
        rectangle.setHeight(5);
        rectangle.setWidth(7);

        int result = rectangle.perimeter();

        assertEquals(24, result);
    }

    protected Rectangle initRectangle() {
        return new Rectangle();
    }

}

public class SquareTest extends RectangleTest {

    @Override
    protected Rectangle initRectangle() {
        return new Square();
    }

}

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