HttpRequest.java

import java.util.*;

import static java.util.Objects.requireNonNull;

public class HttpRequest {
    private final Method method;
    private final String url;
    private final Map<String, String> headers;
    private String body;

    public HttpRequest(Method method, String url) {
        this.method = requireNonNull(method);
        this.url = requireNonNull(url);
        this.body = "";
        this.headers = new HashMap<>();
    }

    public Method getMethod() {
        return method;
    }

    public String getUrl() {
        return url;
    }

    public HttpRequest setBody(String body) {
        this.body = body;
        return this;
    }

    public String getBody() {
        return body;
    }

    public HttpRequest setHeader(String name, String value) {
        headers.put(name, value);
        return this;
    }

    public Set<Map.Entry<String, String>> getHeaders() {
        return Collections.unmodifiableSet(headers.entrySet());
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        HttpRequest that = (HttpRequest) o;
        return method == that.method &&
                Objects.equals(url, that.url) &&
                Objects.equals(headers, that.headers) &&
                Objects.equals(body, that.body);
    }

    @Override
    public int hashCode() {
        return Objects.hash(method, url, headers, body);
    }

    @Override
    public String toString() {
        return "HttpRequest{" +
                "method=" + method +
                ", url='" + url + '\'' +
                ", headers=" + headers +
                ", body='" + body + '\'' +
                '}';
    }

    public enum Method {
        GET, POST
    }
}

HttpRequester.java

/**
 * A wrapper around AsyncHttpClient to facilitate test writing.
 */
public class HttpRequester {
    private final AsyncHttpClient client;

    @Inject
    public HttpRequester() {
        this.client = new DefaultAsyncHttpClient();
    }

    /**
     * Executes the request synchronously.
     *
     * @param request the request to execute.
     * @return http response
     * @throws ExecutionException   when unexpected error happens like timeout.
     * @throws InterruptedException when request thread interrupted.
     */
    public HttpResponse execute(HttpRequest request) throws ExecutionException, InterruptedException {
        Response response = executeAsync(request).get();

        return HttpResponse.newBuilder()
                .setBody(response.getResponseBody())
                .setStatusCode(response.getStatusCode())
                .build();
    }

    private ListenableFuture<Response> executeAsync(HttpRequest request) {
        BoundRequestBuilder builder;

        if (request.getMethod() == HttpRequest.Method.GET) {
            builder = client.prepareGet(request.getUrl());
        } else if (request.getMethod() == HttpRequest.Method.POST) {
            builder = client.preparePost(request.getUrl());
        } else {
            throw new UnsupportedOperationException(request.getMethod() + " not yet supported");
        }

        for (Map.Entry<String, String> header : request.getHeaders()) {
            builder = builder.setHeader(header.getKey(), header.getValue());
        }

        builder = builder.setBody(request.getBody());

        return builder.execute();
    }
}

HttpResponse.java

import java.util.Objects;

public class HttpResponse {
    private final int statusCode;
    private final String body;

    private HttpResponse(Builder builder) {
        statusCode = builder.statusCode;
        body = builder.body;
    }

    public static Builder newBuilder() {
        return new Builder();
    }

    public int getStatusCode() {
        return statusCode;
    }

    public String getBody() {
        return body;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        HttpResponse that = (HttpResponse) o;
        return statusCode == that.statusCode &&
                Objects.equals(body, that.body);
    }

    @Override
    public int hashCode() {
        return Objects.hash(statusCode, body);
    }

    @Override
    public String toString() {
        return "HttpResponse{" +
                "statusCode=" + statusCode +
                ", body='" + body + '\'' +
                '}';
    }

    public static final class Builder {
        private int statusCode;
        private String body;

        private Builder() {
        }

        public Builder setStatusCode(int statusCode) {
            this.statusCode = statusCode;
            return this;
        }

        public Builder setBody(String body) {
            this.body = body;
            return this;
        }

        public HttpResponse build() {
            return new HttpResponse(this);
        }
    }
}