GitHubClient.java

// Copyright 2013 Square, Inc.
package com.example.retrofit;

import retrofit.MockRestAdapter;
import retrofit.RestAdapter;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import java.util.*;

public class GitHubClient
{
  private static final String API_URL = "https://api.github.com";

  static class Contributor
  {
    public final String login;
    public final int    contributions;

    Contributor(String login, int contributions)
    {
      this.login = login;
      this.contributions = contributions;
    }
  }

  public interface GitHub
  {
    @GET
    @Path("/repos/{owner}/{repo}/contributors")
    List<Contributor> contributors(@PathParam("owner") String owner, @PathParam("repo") String repo);
  }

  /**
   * A mock implementation of the {@link GitHub} API interface.
   */
  static class MockGitHub implements GitHub
  {
    private final Map<String, Map<String, List<Contributor>>> ownerRepoContributors;

    public MockGitHub()
    {
      ownerRepoContributors = new LinkedHashMap<String, Map<String, List<Contributor>>>();

      // Seed some mock data.
      addContributor("square", "retrofit", "John Doe", 12);
      addContributor("square", "retrofit", "Bob Smith", 2);
      addContributor("square", "retrofit", "Big Bird", 40);
      addContributor("square", "picasso", "Proposition Joe", 39);
      addContributor("square", "picasso", "Keiser Soze", 152);
    }

    @Override
    public List<Contributor> contributors(String owner, String repo)
    {
      Map<String, List<Contributor>> repoContributors = ownerRepoContributors.get(owner);
      if (repoContributors == null)
      {
        return Collections.emptyList();
      }
      List<Contributor> contributors = repoContributors.get(repo);
      if (contributors == null)
      {
        return Collections.emptyList();
      }
      return contributors;
    }

    public void addContributor(String owner, String repo, String name, int contributions)
    {
      Map<String, List<Contributor>> repoContributors = ownerRepoContributors.get(owner);
      if (repoContributors == null)
      {
        repoContributors = new LinkedHashMap<String, List<Contributor>>();
        ownerRepoContributors.put(owner, repoContributors);
      }
      List<Contributor> contributors = repoContributors.get(repo);
      if (contributors == null)
      {
        contributors = new ArrayList<Contributor>();
        repoContributors.put(repo, contributors);
      }
      contributors.add(new Contributor(name, contributions));
    }
  }

  public static void main(String... args)
  {
    // Create a very simple REST adapter which points the GitHub API endpoint.
    RestAdapter restAdapter = new RestAdapter.Builder()
        .setServer(API_URL)
        .build();

    // Wrap our REST adapter to allow mock implementations and fake network delay.
    MockRestAdapter mockRestAdapter = MockRestAdapter.from(restAdapter);

    // Instantiate a mock object so we can interact with it later.
    MockGitHub mockGitHub = new MockGitHub();
    // Use the mock REST adapter and our mock object to create the API interface.
    GitHub gitHub = mockRestAdapter.create(GitHub.class, mockGitHub);

    // QueryParam for some contributors for a few repositories.
    printContributors(gitHub, "square", "retrofit");
    printContributors(gitHub, "square", "picasso");

    // Using the mock object, add some additional mock data.
    System.out.println("Adding more mock data...\n");
    mockGitHub.addContributor("square", "retrofit", "Foo Bar", 61);
    mockGitHub.addContributor("square", "picasso", "Kit Kat", 53);

    // QueryParam for the contributors again so we can see the mock data that was added.
    printContributors(gitHub, "square", "retrofit");
    printContributors(gitHub, "square", "picasso");
  }

  private static void printContributors(GitHub gitHub, String owner, String repo)
  {
    System.out.println(String.format("== Contributors for %s/%s ==", owner, repo));
    List<Contributor> contributors = gitHub.contributors(owner, repo);
    for (Contributor contributor : contributors)
    {
      System.out.println(contributor.login + " (" + contributor.contributions + ")");
    }
    System.out.println();
  }
}