BlogController.java

package com.knoldus.blogs.controller;

import com.knoldus.blogs.models.Blogs;
import com.knoldus.blogs.models.BlogsUpdateRequest;
import com.knoldus.blogs.repository.BlogRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.Optional;

@RestController
public class BlogController {
    
    @Autowired
    BlogRepository blogRepository;
    
    @RequestMapping("/")
    public String index() {
        return "Welcome to the CRUD application!!";
    }
    
    @PostMapping("/blogs")
    public Blogs addBlogPost(@RequestBody Blogs newBlog) {
        return blogRepository.save(newBlog);
    }
    
    @GetMapping("/blogs/{id}")
    public Optional<Blogs> getBlog(@PathVariable String id) {
        if (blogRepository.existsById(id)) {
            return blogRepository.findById(id);
        } else
            return Optional.empty();
    }
    
    @GetMapping("/blogs/author/{author}")
    public Blogs getBlogByAuthorName(@PathVariable String author) {
        return blogRepository.findByAuthor(author);
    }
    
    @DeleteMapping("/blogs/topic/{topic}/author/{author}")
    public List<Blogs> deleteByAuthorAndTopic(@PathVariable String topic, @PathVariable String author) {
        return blogRepository.deleteBytopicAndAuthor(topic, author);
    }
    
    @DeleteMapping("/blogs/{id}")
    public void deleteById(@PathVariable String id) {
        blogRepository.deleteById(id);
    }
    
    @PutMapping("/blogs/{idToBeUpdated}")
    public String updateBlog(@PathVariable String idToBeUpdated, @RequestBody BlogsUpdateRequest blogsUpdateRequest) {
        
        Optional<Blogs> mayBeBlog = blogRepository.findById(idToBeUpdated)
                .map(blogs -> blogRepository
                        .save(Blogs
                                .builder()
                                .id(idToBeUpdated)
                                .topic(blogsUpdateRequest.getTopic())
                                .tags(blogsUpdateRequest.getTags())
                                .author(blogs.getAuthor())
                                .date(blogs.getDate())
                                .build())
                );
        if (mayBeBlog.isPresent()) {
            return "Blog Updated";
        } else {
            return "Blog does not exist";
        }
    }
}