content: package com.erichgamma.api.post;
  
  import com.erichgamma.api.common.AbstractService;
  import com.erichgamma.api.enums.Messenger;
  import lombok.Getter;
  
  import java.sql.SQLException;
  import java.util.List;
  import java.util.Optional;
  
  public class PostServiceImpl extends AbstractService<Post> implements PostService {
      @Getter
      private static final PostServiceImpl instance = new PostServiceImpl();
      private PostRepository postRepository;
      private PostServiceImpl(){
          postRepository = PostRepository.getInstance();
      }
  
      @Override
      public Messenger save(Post post) {
          return null;
      }
  
      @Override
      public Messenger delete(Post post) {
          return null;
      }
  
      @Override
      public Messenger deleteAll() {
          return null;
      }
  
      @Override
      public List<Post> findAll()  throws SQLException {
          return postRepository.findAll();
      }
  
      @Override
      public Optional<Post> findById(Long id) {
          return Optional.empty();
      }
  
      @Override
      public Long count() {
          return null;
      }
  
      @Override
      public Optional<Post> getOne(String id) throws SQLException {
          return Optional.empty();
      }
  
      @Override
      public Boolean existsById(Long id) {
          return null;
      }
  }
  