Volley network core use OkHttp

OkStack.java

public class OKStack implements HttpStack {

	OkHttpClient client = new OkHttpClient();
	public static final String HEADER_CONTENT_TYPE = "Content-Type";

	@Override
	public HttpResponse performRequest(Request<?> request, Map<String, String> additionalHeaders) throws IOException,
			AuthFailureError {
		URL url = new URL(request.getUrl());
		
		client.setReadTimeout(request.getTimeoutMs(), TimeUnit.MILLISECONDS);
		client.setConnectTimeout(request.getTimeoutMs(), TimeUnit.MILLISECONDS);
		HttpURLConnection conn = client.open(url);
		conn.setUseCaches(false);
		conn.setDoInput(true);
		
		Map<String, String> params = new HashMap<String, String>();
		params.putAll(additionalHeaders);
		params.putAll(request.getHeaders());
		for (Entry<String, String> entry : params.entrySet())
			conn.addRequestProperty(entry.getKey(), entry.getValue());
		
		setRequestMethod(conn, request);
		ProtocolVersion version = new ProtocolVersion("http", 1, 1);
		int code = conn.getResponseCode();
		if (code == -1) {
			throw new IOException("Could not retrieve response code from Connection");
		}
		StatusLine state = new BasicStatusLine(version, code, conn.getResponseMessage());
		BasicHttpResponse response = new BasicHttpResponse(state);
		response.setEntity(buildResponseEntity(conn));
		for (Entry<String, List<String>> item : conn.getHeaderFields().entrySet()) {
			if (item.getKey() != null) {
				Header head = new BasicHeader(item.getKey(), item.getValue().get(0));
				response.setHeader(head);
			}
		}
		return response;
	}

	HttpEntity buildResponseEntity(HttpURLConnection conn) {
		BasicHttpEntity entity = new BasicHttpEntity();
		InputStream is;
		try {
			is = conn.getInputStream();
		} catch (IOException e) {
			is = conn.getErrorStream();
		}
		entity.setContent(is);
		entity.setContentEncoding(conn.getContentEncoding());
		entity.setContentLength(conn.getContentLength());
		entity.setContentType(conn.getContentType());
		return entity;
	}

	void addBody(HttpURLConnection conn, Request<?> request) throws AuthFailureError, IOException {
		byte[] body = request.getBody();
		if (body != null) {
			conn.setDoOutput(true);
			conn.addRequestProperty(HEADER_CONTENT_TYPE, request.getBodyContentType());
			DataOutputStream os = new DataOutputStream(conn.getOutputStream());
			os.write(body);
			os.close();
		}
	}

	void setRequestMethod(HttpURLConnection conn, Request<?> request) throws AuthFailureError, IOException {
		switch (request.getMethod()) {
		case Method.DEPRECATED_GET_OR_POST:
			byte[] body = request.getBody();
			if (body != null) {
				conn.setDoOutput(true);
				conn.setRequestMethod("POST");
				conn.addRequestProperty(HEADER_CONTENT_TYPE, request.getBodyContentType());
				DataOutputStream os = new DataOutputStream(conn.getOutputStream());
				os.write(body);
				os.close();
			}
			break;
		case Method.POST:
			conn.setRequestMethod("POST");
			addBody(conn, request);
			break;
		case Method.PUT:
			conn.setRequestMethod("PUT");
			addBody(conn, request);
			break;
		case Method.GET:
			conn.setRequestMethod("GET");
			break;
		case Method.DELETE:
			conn.setRequestMethod("DELETE");
			break;
		default:
			throw new IllegalStateException("Unkonw Request Method.");
		}
	}
}