170608(목) - DI with Dagger2

DI with Dagger2

http://kunny.github.io/life/2016/06/06/dagger2_resources/

How do we avoid the boilerplate that comes with the pattern?

1. 기존 소스

public calss Tweeter {

public void tweet(String tweet) {

TwitterApi api = new TwitterApi();

api.postTweet("신대규", tweet);

}

}

public class TwitterApi {

public void postTweet(String user, String tweet) {

OkHttpClient client = new OkHttpClient();

Request request = ...

client.newCall(request).execute();

}

}

Tweeter tweeter = new Tweeter();

tweeter.tweet("Hello, #Devoxx 2014!");

2. 개선

public class TwitterApi {

private final OkHttpClient client;

public TwitterApi(OkHttpClient client) {

this.client = client;

}

public void postTweet(String user, String tweet) {

OkHttpClient client = new OkHttpClient();

Request request = ...

client.newCall(request).execute();

}

}

public calss Tweeter {

private final TwitterApi api = new TwitterApi(new OkHttpClient());

private final String user;

public Tweeter(String user) {

this.user = user;

}

public void tweet(String tweet) {

api.postTweet(user, tweet);

}

}

Tweeter tweeter = new Tweeter("신대규");

tweeter.tweet("Hello, #Devoxx 2014!");

3. (more)기존코드

Timeline timeline = new Timeline("신대규");

timeline.loadMore(20);

for (Tweet tweet : timeline.get()) {

System.out.println(tweet);

}

public class Timeline() {

private final List<Tweet> cache = new ArrayList<>();

private final TwitterApi api = new TwitterApi(new OkHttpClient());

private final String user;

public Timeline(String user);

this.user = user;

}

public List<Tweet> get() {   

...

}

public void loadMore(int amount) {

...

}

}

4. (more) 개선

public class Timeline() {

private final List<Tweet> cache = new ArrayList<>();

private final TwitterApi api = new TwitterApi(new OkHttpClient());;

private final String user;

public Timeline(TwitterApi api, String user);

this.api = api;

this.user = user;

}

public List<Tweet> get() {   

...

}

public void loadMore(int amount) {

...

}

}

public calss Tweeter {

private final TwitterApi api = new TwitterApi(new OkHttpClient());;;

private final String user;

public Tweeter(TwitterApi api, String user) {

this.api = api;

this.user = user;

}

public void tweet(String tweet) {

api.postTweet(user, tweet);

}

}

OkHttpClient client = new OkHttpClient();

TwitterApi api = new TwitterApi(client);

String user = "신대규";

Tweeter tweeter = new Tweeter(api, user);

tweeter.tweet("Hello, #Devoxx 2014!");

Timeline timeline = new Timeline(api, user);

timeline.loadMore(20);

for (Tweet tweet : timeline.get()) {

System.out.println(tweet);

}