hello ribbon

GreetingController.java

package com.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.hateoas.Resources;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.Optional;

@RestController
public class GreetingController {

    private static class AlbumResources extends Resources<Album> { }

    private String greeting;
    private final RestTemplate restTemplate;

    @Autowired
    public GreetingController(RestTemplate restTemplate, @Value("${greeting:Hello unknown}") String greeting) {
        this.greeting = greeting;
        this.restTemplate = restTemplate;
    }

    @GetMapping("/")
    public String greet() {
        String url = "http://zenika-music/albums";
        Optional<AlbumResources> albums;

        try {
            albums = Optional.of(restTemplate.getForObject(url, AlbumResources.class));
        } catch (Exception e) {
            albums = Optional.empty();
        }

        String albumsSummary = albums.map(it -> "There are " + it.getContent().size() + " albums. ")
                .orElse("We don't know how many albums there are. ");
        return greeting + albumsSummary;
    }

}