手写单例和组合模式运用实例

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发布于: 2020 年 06 月 24 日
手写单例两种实现方式：
1、懒汉式；
2、饿汉式。
如下图：
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一个组合模式实例请用组合设计模式编写程序，打印输出图 1 的窗口，窗口组件的树结构如图 2 所示，打印输出示例参考图 3。
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代码实现如下：
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1、定义组件抽象
package study;
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/**
 * @author linyurong
 * @date 2020/6/24 9:52
 */
public interface Component {
    /**
     * 打印
     */
    void print();
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    /**
     * 添加子组件
     * @param child
     */
    void addChild(Component child);
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    /**
     * 删除子组件
     * @param child
     */
    void removeChild(Component child);
}
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2、定义一个实现基类：
package study;
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import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
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/**
 * @author linyurong
 * @date 2020/6/24 9:55
 */
public class BaseComponent implements Component {
    private String name;
    protected List<Component> childList;
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    public BaseComponent() {}
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    public BaseComponent(String name) {
        this.name = name;
        this.childList = new ArrayList<>(16);
    }
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    @Override
    public void print() {
        System.out.printf("print %s(%s)\n", getClass().getSimpleName(), name);
        for (Component child : childList) {
            child.print();
        }
    }
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    @Override
    public void addChild(Component child) {
        if (Objects.nonNull(child)) {
            childList.add(child);
        }
    }
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    @Override
    public void removeChild(Component child) {
        childList.remove(child);
    }
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    @Override
    public boolean equals(Object obj) {
        return super.equals(obj);
    }
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    @Override
    public int hashCode() {
        return super.hashCode();
    }
}
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3、定义出各种组件，继承上述基类，重新构造方法
package study;
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/**
 * @author linyurong
 * @date 2020/6/24 10:01
 */
public class WinForm extends BaseComponent {
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    public WinForm(String name) {
        super(name);
    }
}
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public class Button extends BaseComponent {
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    public Button(String name) {
        super(name);
    }
}
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public class CheckBox extends BaseComponent {
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    public CheckBox(String name) {
        super(name);
    }
}
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public class Frame extends BaseComponent {
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    public Frame(String name) {
        super(name);
    }
}
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public class Label extends BaseComponent {
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    public Label(String name) {
        super(name);
    }
}
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public class LinkLabel extends BaseComponent {
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    public LinkLabel(String name) {
        super(name);
    }
}
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public class PasswordBox extends BaseComponent {
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    public PasswordBox(String name) {
        super(name);
    }
}
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public class Picture extends BaseComponent {
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    public Picture(String name) {
        super(name);
    }
}
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public class TextBox extends BaseComponent {
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    public TextBox(String name) {
        super(name);
    }
}
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4、客户端实现类
package study;
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/**
 * @author linyurong
 * @date 2020/6/24 10:02
 */
public class Main {
    public static void main(String[] args) {
        WinForm winForm = new WinForm("WINDOW窗口");
        winForm.addChild(new Picture("LOGO图片"));
        winForm.addChild(new Button("登录"));
        winForm.addChild(new Button("注册"));
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        Frame frame = new Frame("Frame1");
        frame.addChild(new Label("用户名"));
        frame.addChild(new TextBox("文本框"));
        frame.addChild(new Label("密码"));
        frame.addChild(new PasswordBox("密码框"));
        frame.addChild(new CheckBox("复选框"));
        frame.addChild(new TextBox("记住用户名"));
        frame.addChild(new LinkLabel("忘记密码"));
        winForm.addChild(frame);
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        winForm.print();
    }
}
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5、运行结果
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