设计模式原则(开闭原则，里氏替换原则，依赖倒置原则）

理解开闭原则，实现以下样例

public abstract class AbstractButton {
	public abstract void view();
}

public class CircleButton extends AbstractButton{

	@Override
	public void view() {
		// TODO Auto-generated method stub
		System.out.println("CircleButton view ...");
	}
	
}

public class RectangleButton extends AbstractButton{

	@Override
	public void view() {
		// TODO Auto-generated method stub
		System.out.println("RectangleButton view ...");
	}

}

public class LoginForm {

	public void display(AbstractButton button) {
		button.view();
	}
}

public class LoginTest {

	public static void main(String[] args) {
		AbstractButton circleButton = new CircleButton();
		AbstractButton rectangleButton = new RectangleButton();
		LoginForm loginForm = new LoginForm();
		loginForm.display(circleButton);
		loginForm.display(rectangleButton);
	}

}

理解里氏替换原则，实现以下样例

public class Animal {
	public double runSpeed;

	public double getRunSpeed() {
		return runSpeed;
	}

	public void setRunSpeed(double runSpeed) {
		this.runSpeed = runSpeed;
	}
	
}

public class Bird extends Animal{
	public double flySpeed;

	public double getFlySpeed() {
		return flySpeed;
	}

	public void setFlySpeed(double flySpeed) {
		this.flySpeed = flySpeed;
	}
	
	 public double getFlyTime(double distance) {
	        return (distance / flySpeed);
	    }
}

public class BrownKiwi extends Bird {
	@Override
	public void setRunSpeed(double runSpeed) {
		flySpeed = 0;
	}
}

public class Swallow extends Bird{

}

public class LSPtest {
	public static void main(String[] args) {
		Bird bird1 = new Swallow();
		Bird bird2 = new BrownKiwi();
		bird1.setFlySpeed(120);
		bird2.setFlySpeed(150);
		System.out.println("如果飞行300公里：");
		try {
			System.out.println("燕子将飞行" + bird1.getFlyTime(300) + "小时.");
			System.out.println("几维鸟将飞行" + bird2.getFlyTime(300) + "小时。");
		} catch (Exception err) {
			System.out.println("发生错误了!");
		}
	}
}

理解依赖倒转原则，实现以下样例

public abstract class AbstractSource {
	public abstract String source();
}

public abstract class AbstractTransformer {
	public abstract String transform();
}

public class DatabaseSource extends AbstractSource{

	@Override
	public String source() {
		// TODO Auto-generated method stub
		return "DatabaseSource";
	}
}

public class TextSource extends AbstractSource {

	@Override
	public String source() {
		// TODO Auto-generated method stub
		return "TextSource";
	}
}

public class XLSTTransformer extends AbstractTransformer{

	@Override
	public String transform() {
		// TODO Auto-generated method stub
		return "XLSTTransformer";
	}
}

public class XMLTransformer extends AbstractTransformer{

	@Override
	public String transform() {
		// TODO Auto-generated method stub
		return "XMLTransformer";
	}
}

public class MainClass {

	public static void main(String[] args) {
		AbstractSource s1 = new DatabaseSource();
		AbstractSource s2 = new TextSource();
		System.out.println(s1.source());
		System.out.println(s2.source());
		System.out.println("-----------------------------------------");
		AbstractTransformer t1 = new XLSTTransformer();
		AbstractTransformer t2 = new XMLTransformer();
		System.out.println(t1.transform());
		System.out.println(t2.transform());
	}
}