23种设计模式（10）- 组合模式

public abstract class FolderComponent {
  private String name;

  public String getName() {
    return name;
  }

  public void setName(final String name) {
    this.name = name;
  }

  public FolderComponent() {
  }

  public FolderComponent(final String name) {
    this.name = name;
  }

  public abstract void add(FolderComponent component);

  public abstract void remove(FolderComponent component);

  public abstract void display();
}

public class FileLeaf extends FolderComponent {
  public FileLeaf(final String name) {
    super(name);
  }

  @Override
  public void add(final FolderComponent component) {
    // ...
  }

  @Override
  public void remove(final FolderComponent component) {
    // ...
  }

  @Override
  public void display() {
    System.out.println("FileLeaf:" + this.getName());
  }
}

public class FolderComposite extends FolderComponent {
  private final List<FolderComponent> components;

  public FolderComposite(final String name) {
    super(name);
    this.components = new ArrayList<FolderComponent>();
  }

  public FolderComposite() {
    this.components = new ArrayList<FolderComponent>();
  }

  @Override
  public void add(final FolderComponent component) {
    this.components.add(component);
  }

  @Override
  public void remove(final FolderComponent component) {
    this.components.remove(component);
  }

  @Override
  public void display() {
    System.out.println("FolderComposite---name:" + this.getName());
    for (final FolderComponent component : components) {
      System.out.println("FolderComposite---component-name:" + component.getName());
    }
  }
}

public class Client
{
    public static void main(final String[] args)
    {
        final FolderComponent leaf = new FileLeaf("runnable file");
        leaf.display();

        final FolderComponent folder = new FolderComposite("new folder");
        folder.add(new FileLeaf("content1 in new folder"));
        folder.add(new FileLeaf("content2 in new folder"));
        folder.display();
    }
}

FileLeaf:runnable file
FolderComposite---name:new folder
FolderComposite---component-name:content1 in new folder
FolderComposite---component-name:content2 in new folder