【设计模式】JAVA Design Patterns——Callback（回调模式）

public interface Callback {
 
  void call();
}

public abstract class Task {
 
  final void executeWith(Callback callback) {
    execute();
    Optional.ofNullable(callback).ifPresent(Callback::call);
  }
 
  public abstract void execute();
}
 
public final class SimpleTask extends Task {
 
  private static final Logger LOGGER = getLogger(SimpleTask.class);
 
  @Override
  public void execute() {
    LOGGER.info("Perform some important activity and after call the callback method.");
  }
}

    var task = new SimpleTask();
    task.executeWith(() -> LOGGER.info("I'm done now."));