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/*
* Copyright 2013 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package feign.examples;
import com.google.gson.Gson;
import com.google.gson.JsonIOException;
import com.google.gson.stream.JsonReader;
import dagger.Module;
import dagger.Provides;
import feign.Feign;
import feign.Logger;
import feign.Observable;
import feign.Observer;
import feign.RequestLine;
import feign.codec.Decoder;
import feign.codec.IncrementalDecoder;
import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;
import java.io.IOException;
import java.io.Reader;
import java.lang.reflect.Type;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import static dagger.Provides.Type.SET;
/**
* adapted from {@code com.example.retrofit.GitHubClient}
*/
public class GitHubExample {
interface GitHub {
@RequestLine("GET /repos/{owner}/{repo}/contributors")
List<Contributor> contributors(@Named("owner") String owner, @Named("repo") String repo);
@RequestLine("GET /repos/{owner}/{repo}/contributors")
Observable<Contributor> observable(@Named("owner") String owner, @Named("repo") String repo);
}
static class Contributor {
String login;
int contributions;
}
public static void main(String... args) throws InterruptedException {
GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GitHubModule());
System.out.println("Let's fetch and print a list of the contributors to this library.");
List<Contributor> contributors = github.contributors("netflix", "feign");
for (Contributor contributor : contributors) {
System.out.println(contributor.login + " (" + contributor.contributions + ")");
}
System.out.println("Let's treat our contributors as an observable.");
Observable<Contributor> observable = github.observable("netflix", "feign");
CountDownLatch latch = new CountDownLatch(2);
System.out.println("Let's add 2 subscribers.");
observable.subscribe(new ContributorObserver(latch));
observable.subscribe(new ContributorObserver(latch));
// wait for the task to complete.
latch.await();
System.exit(0);
}
@Module(overrides = true, library = true, includes = GsonModule.class)
static class GitHubModule {
@Provides Logger.Level loggingLevel() {
return Logger.Level.BASIC;
}
@Provides Logger logger() {
return new Logger.ErrorLogger();
}
}
/**
* Here's how it looks to wire json codecs. Note, that you can always instead use {@code feign-gson}!
*/
@Module(library = true)
static class GsonModule {
@Provides @Singleton Gson gson() {
return new Gson();
}
@Provides(type = SET) Decoder decoder(GsonDecoder gsonDecoder) {
return gsonDecoder;
}
@Provides(type = SET) IncrementalDecoder incrementalDecoder(GsonDecoder gsonDecoder) {
return gsonDecoder;
}
}
static class GsonDecoder implements Decoder.TextStream<Object>, IncrementalDecoder.TextStream<Object> {
private final Gson gson;
@Inject GsonDecoder(Gson gson) {
this.gson = gson;
}
@Override public Object decode(Reader reader, Type type) throws IOException {
return fromJson(new JsonReader(reader), type);
}
@Override
public void decode(Reader reader, Type type, Observer<? super Object> observer, AtomicBoolean subscribed) throws IOException {
JsonReader jsonReader = new JsonReader(reader);
jsonReader.beginArray();
while (jsonReader.hasNext() && subscribed.get()) {
observer.onNext(fromJson(jsonReader, type));
}
}
private Object fromJson(JsonReader jsonReader, Type type) throws IOException {
try {
return gson.fromJson(jsonReader, type);
} catch (JsonIOException e) {
if (e.getCause() != null && e.getCause() instanceof IOException) {
throw IOException.class.cast(e.getCause());
}
throw e;
}
}
}
static class ContributorObserver implements Observer<Contributor> {
private final CountDownLatch latch;
public int count;
public ContributorObserver(CountDownLatch latch) {
this.latch = latch;
}
// parsed directly from the text stream without an intermediate collection.
@Override public void onNext(Contributor contributor) {
count++;
}
@Override public void onSuccess() {
System.out.println("found " + count + " contributors");
latch.countDown();
}
@Override public void onFailure(Throwable cause) {
cause.printStackTrace();
latch.countDown();
}
}
}