Add services responsible for fetching data from GitHub API. Add domai…

…n classes. Add tests for same layer.

.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+github.token
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/

build.gradle

@@ -14,9 +14,20 @@ repositories {
 
 dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation "org.assertj:assertj-vavr:0.2.0"
+
+    compile 'javax.inject:javax.inject:1'
+    compile 'io.vavr:vavr:0.10.2'
+
+    compileOnly 'org.projectlombok:lombok:1.18.10'
+
+    annotationProcessor 'org.projectlombok:lombok:1.18.10'
+
     testImplementation('org.springframework.boot:spring-boot-starter-test') {
         exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
     }
+
+    testCompile("org.assertj:assertj-core:3.11.1")
 }
 
 test {

lombok.config

@@ -0,0 +1 @@
+lombok.anyConstructor.addConstructorProperties = true

src/main/java/com/gosiewski/contributorsjava/ContributorsJavaApplication.java

@@ -2,10 +2,17 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.web.client.RestTemplate;
 
 @SpringBootApplication
 public class ContributorsJavaApplication {
 
+    @Bean
+    public RestTemplate restTemplate() {
+        return new RestTemplate();
+    }
+
     public static void main(String[] args) {
         SpringApplication.run(ContributorsJavaApplication.class, args);
     }

src/main/java/com/gosiewski/contributorsjava/dto/incoming/ContributorRequestDto.java

@@ -0,0 +1,9 @@
+package com.gosiewski.contributorsjava.dto.incoming;
+
+import lombok.Value;
+
+@Value
+public final class ContributorRequestDto {
+    private final String login;
+    private final int contributions;
+}

src/main/java/com/gosiewski/contributorsjava/dto/incoming/RepositoryRequestDto.java

@@ -0,0 +1,8 @@
+package com.gosiewski.contributorsjava.dto.incoming;
+
+import lombok.Value;
+
+@Value
+public final class RepositoryRequestDto {
+    private String name;
+}

src/main/java/com/gosiewski/contributorsjava/dto/outgoing/ContributorDto.java

@@ -0,0 +1,9 @@
+package com.gosiewski.contributorsjava.dto.outgoing;
+
+import lombok.Value;
+
+@Value
+public class ContributorDto {
+    private String name;
+    private int contributions;
+}

src/main/java/com/gosiewski/contributorsjava/error/ApiCallError.java

@@ -0,0 +1,7 @@
+package com.gosiewski.contributorsjava.error;
+
+public final class ApiCallError extends Error {
+    public ApiCallError() {
+        super("External HTTP response was different than expected.");
+    }
+}

src/main/java/com/gosiewski/contributorsjava/error/Error.java

@@ -0,0 +1,10 @@
+package com.gosiewski.contributorsjava.error;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public abstract class Error {
+    private final String reason;
+}

src/main/java/com/gosiewski/contributorsjava/error/IllegalArgumentError.java

@@ -0,0 +1,7 @@
+package com.gosiewski.contributorsjava.error;
+
+public final class IllegalArgumentError extends Error {
+    public IllegalArgumentError(String reason) {
+        super(reason);
+    }
+}

src/main/java/com/gosiewski/contributorsjava/error/NotFoundError.java

@@ -0,0 +1,7 @@
+package com.gosiewski.contributorsjava.error;
+
+public final class NotFoundError extends Error {
+    public NotFoundError() {
+        super("Not found");
+    }
+}

src/main/java/com/gosiewski/contributorsjava/service/GitHubAPIService.java

@@ -0,0 +1,102 @@
+package com.gosiewski.contributorsjava.service;
+
+import com.gosiewski.contributorsjava.dto.incoming.ContributorRequestDto;
+import com.gosiewski.contributorsjava.dto.incoming.RepositoryRequestDto;
+import com.gosiewski.contributorsjava.error.ApiCallError;
+import com.gosiewski.contributorsjava.error.Error;
+import com.gosiewski.contributorsjava.error.IllegalArgumentError;
+import com.gosiewski.contributorsjava.service.domain.Contributor;
+import com.gosiewski.contributorsjava.service.domain.Repository;
+import io.vavr.collection.List;
+import io.vavr.collection.Seq;
+import io.vavr.control.Either;
+import lombok.RequiredArgsConstructor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+
+import java.util.ArrayList;
+
+@Service
+@RequiredArgsConstructor
+public class GitHubAPIService {
+    final static Logger logger = LoggerFactory.getLogger(GitHubAPIService.class);
+
+    private final static String REPOS_URL = "https://api.github.com/orgs/%1$s/repos";
+    private final static String CONTRIBUTORS_URL = "https://api.github.com/repos/%1$s/%2$s/contributors";
+
+    private final HttpClient httpClient;
+
+    final Either<Error, Seq<Repository>> getOrganizationRepos(final String organizationName) {
+        if (organizationName.isBlank()) {
+            return Either.left(new IllegalArgumentError("Organization name cannot be blank."));
+        }
+
+        final String url = String.format(REPOS_URL, organizationName);
+
+        return getFullGitHubResource(url, RepositoryRequestDto.class).map(this::mapRepositoryDtos);
+    }
+
+    final Either<Error, Seq<Contributor>> getRepoContributors(final String ownerName,
+                                                              final String repoName) {
+        if (ownerName.isBlank() || repoName.isBlank()) {
+            return Either.left(new IllegalArgumentError("Owner name or repo name cannot be blank."));
+        }
+
+        final String url = String.format(CONTRIBUTORS_URL, ownerName, repoName);
+
+        return getFullGitHubResource(url, ContributorRequestDto.class).map(this::mapContributorDtos);
+    }
+
+    private <T> Either<Error, Seq<T>> getFullGitHubResource(final String url, final Class<T> clazz) {
+        Either<Error, ResponseEntity<java.util.List<T>>> result = httpClient.fetchFirstPage(url, clazz);
+
+        if (result.isLeft()) {
+            return Either.left(result.getLeft());
+        }
+
+        ResponseEntity<java.util.List<T>> response = result.get();
+
+        if (response.getBody() == null) {
+            logEmptyBodyError(response.toString());
+
+            return Either.left(new ApiCallError());
+        }
+
+        final java.util.List<T> fullResult = new ArrayList<>(response.getBody());
+
+        while(httpClient.hasNextPage(response.getHeaders())) {
+            result = httpClient.fetchNextPage(response, clazz);
+
+            if (result.isLeft()) {
+                return Either.left(result.getLeft());
+            }
+
+            response = result.get();
+
+            if (response.getBody() == null) {
+                logEmptyBodyError(response.toString());
+
+                return Either.left(new ApiCallError());
+            }
+
+            fullResult.addAll(response.getBody());
+        }
+
+        return Either.right(List.ofAll(fullResult));
+    }
+
+    private Seq<Contributor> mapContributorDtos(final Seq<ContributorRequestDto> dtos) {
+        return dtos.map(contributorDto -> new Contributor(contributorDto.getLogin(), contributorDto.getContributions()));
+    }
+
+    private Seq<Repository> mapRepositoryDtos(final Seq<RepositoryRequestDto> dtos) {
+        return dtos.map(repositoryDto -> new Repository(repositoryDto.getName()));
+    }
+
+    private void logEmptyBodyError(final String response) {
+        logger.error("GitHub responded with empty body:");
+        logger.error(response);
+    }
+}