Java设计模式之组合模式详解

// 组件抽象类
public abstract class Component {
    protected String name;
    public Component(String name) {
        this.name = name;
    }
    public abstract void operation();
}
// 叶子节点
public class Leaf extends Component {
    public Leaf(String name) {
        super(name);
    }
    @Override
    public void operation() {
        System.out.println("Leaf " + name + " is operated.");
    }
}
// 组合节点
public class Composite extends Component {
    private List<Component> children = new ArrayList<>();
    public Composite(String name) {
        super(name);
    }
    public void add(Component component) {
        children.add(component);
    }
    public void remove(Component component) {
        children.remove(component);
    }
    @Override
    public void operation() {
        System.out.println("Composite " + name + " is operated.");
        for (Component component : children) {
            component.operation();
        }
    }
}

// 文件系统示例
public class FileSystemDemo {
    public static void main(String[] args) {
        Component file1 = new Leaf("file1.txt");
        Component file2 = new Leaf("file2.txt");
        Component folder1 = new Composite("Folder 1");
        folder1.add(file1);
        folder1.add(file2);
        Component file3 = new Leaf("file3.txt");
        Component file4 = new Leaf("file4.txt");
        Component folder2 = new Composite("Folder 2");
        folder2.add(file3);
        folder2.add(file4);
        Component root = new Composite("Root");
        root.add(folder1);
        root.add(folder2);
        root.operation();
    }
}