2017你不應該錯過的Java庫包

# Typical dependency injection
public class DatabaseTransactionLogProvider implements Provider<TransactionLog> {
  @Inject Connection connection;
  public TransactionLog get() {
    return new DatabaseTransactionLog(connection);
  }
}
# FactoryModuleBuilder generates factory using your interface
public interface PaymentFactory {
   Payment create(Date startDate, Money amount);
 }
<p class="indent">

OkHttpClient client = new OkHttpClient();

String run(String url) throws IOException {
  Request request = new Request.Builder()
      .url(url)
      .build();

  Response response = client.newCall(request).execute();
  return response.body().string();
}
<p class="indent">

public interface GitHubService {
    @GET("users/{user}/repos")
    Call<List<Repo>listRepos(@Path("user") String user);
}
<p class="indent">

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("https://api.github.com/")
    .build();
 
GitHubService service = retrofit.create(GitHubService.class);
<p class="indent">

Call<List<Repo>> repos = service.listRepos("octocat");
<p class="indent">

Flowable.fromCallable(() -{
     Thread.sleep(1000); //  imitate expensive computation
     return "Done";
 })
   .subscribeOn(Schedulers.io())
   .observeOn(Schedulers.single())
   .subscribe(System.out::println, Throwable::printStackTrace);
 
 Thread.sleep(2000); // <--- wait for the flow to finish
<p class="indent">

// Define your listener
class SimpleFileListener{
    @Handler
    public void handle(File msg){
      // do something with the file
    }
}

// somewhere else in your code
MBassador bus = new MBassador();
Object listener = new SimpleFileListener();
bus.subscribe (listener);
bus.post(new File("/tmp/smallfile.csv")).now();
bus.post(new File("/tmp/bigfile.csv")).asynchronously();
<p class="indent">

       @Test
       @Parameters({"17, false", 
                    "22, true" })
       public void personIsAdult(int age, boolean valid) throws Exception {
         assertThat(new Person(age).isAdult(), is(valid));
       }
<p class="indent">

//你可以模擬具體的類，而不僅僅是介面
 LinkedList mockedList = mock(LinkedList.class);

 //stubbing
 when(mockedList.get(0)).thenReturn("first");
 when(mockedList.get(1)).thenThrow(new RuntimeException());

 //將列印 "first"
 System.out.println(mockedList.get(0));

 //將丟擲runtime exception
 System.out.println(mockedList.get(1));

 //將列印 "null" 因為get(999)沒有被stubbed
 System.out.println(mockedList.get(999));

 //Although it is possible to verify a stubbed invocation, usually it's just redundant
 //If your code cares what get(0) returns, then something else breaks (often even before verify() gets executed).
 //If your code doesn't care what get(0) returns, then it should not be stubbed. Not convinced? See here.
 verify(mockedList).get(0);
<p class="indent">

@RunWith(JukitoRunner.class)
public class EmailSystemTest {

  @Inject EmailSystemImpl emailSystem;
  Email dummyEmail;

  @Before
  public void setupMocks(
      IncomingEmails incomingEmails,
      EmailFactory factory) {
    dummyEmail = factory.createDummy();
    when(incomingEmails.count()).thenReturn(1);
    when(incomingEmails.get(0)).thenReturn(dummyEmail);
  }

  @Test
  public void shouldFetchEmailWhenStarting(
      EmailView emailView) {
    // WHEN
    emailSystem.start();

    // THEN
    verify(emailView).addEmail(dummyEmail);
  }
}
<p class="indent">

@Test
public void updatesCustomerStatus() throws Exception {
    // Publish an asynchronous event:
    publishEvent(updateCustomerStatusEvent);
    // Awaitility讓你等待非同步操作完成
    await().atMost(5, SECONDS).until(customerStatusIsUpdated());
    ...
}
<p class="indent">

class HelloSpockSpec extends spock.lang.Specification {
  def "length of Spock's and his friends' names"() {
    expect:
    name.size() == length

    where:
    name     | length
    "Spock"  | 5
    "Kirk"   | 4
    "Scotty" | 6
  }
}  
<p class="indent">

{
    "request": {
        "method": "GET",
        "url": "/some/thing"
    },
    "response": {
        "status": 200,
        "statusMessage": "Everything was just fine!"
    }
}

<p class="indent">