Java tutorial
/* Copyright 2017 Arlind Rufi Copyright 2017 Gianmario Pozzi Copyright 2017 Giorgio Pea 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 it.polimi.diceH2020.plugin.net; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.util.List; import org.apache.commons.io.IOUtils; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.ContentType; import org.apache.http.entity.mime.MultipartEntityBuilder; import org.apache.http.entity.mime.content.FileBody; import org.apache.http.entity.mime.content.StringBody; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.EntityUtils; import org.json.simple.JSONArray; import org.json.simple.JSONObject; import org.json.simple.parser.JSONParser; import org.json.simple.parser.ParseException; import it.polimi.diceH2020.plugin.control.Configuration; import it.polimi.diceH2020.plugin.preferences.Preferences; /** * Manages interaction with the backend * * @author Giorgio Pea <giorgio.pea@mail.polimi.it> */ public class NetworkManager { private static NetworkManager instance; private static String rootEndpoint = Preferences.getFrontEndUrl(); private static String vmConfigsEndpoint = Preferences.getBackEndUrl() + "vm-types"; private static String uploadRest = rootEndpoint + "/files/upload"; public static NetworkManager getInstance() { if (instance != null) { return instance; } instance = new NetworkManager(); return instance; } private NetworkManager() { System.setProperty("org.apache.commons.logging.Log", "org.apache.commons.logging.impl.SimpleLog"); System.setProperty("org.apache.commons.logging.simplelog.showdatetime", "true"); System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http.wire", "DEBUG"); } /** * Fetches vm configurations from the web * * @return A json object representing the fetched vm configurations */ public JSONArray fetchVmConfigs() { CloseableHttpClient httpclient = HttpClients.createDefault(); HttpGet httpget = new HttpGet(vmConfigsEndpoint); CloseableHttpResponse response; String body; JSONParser parser; try { response = httpclient.execute(httpget); if (response.getStatusLine().getStatusCode() != 200) { return null; } else { // Converts response stream into string in order to parse // everything int json body = IOUtils.toString(response.getEntity().getContent(), "UTF-8"); parser = new JSONParser(); response.close(); return ((JSONArray) parser.parse(body)); } } catch (UnsupportedOperationException | ParseException | IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } /** * Sends to the backend the models to be simulated * * @param files * The model files * @param scenario * The scenario parameter * @throws UnsupportedEncodingException */ public void sendModel(List<File> files, String scenario) throws UnsupportedEncodingException { HttpClient httpclient = HttpClients.createDefault(); HttpResponse response; HttpPost post = new HttpPost(uploadRest); MultipartEntityBuilder builder = MultipartEntityBuilder.create(); builder.addPart("scenario", new StringBody(scenario, ContentType.DEFAULT_TEXT)); for (File file : files) { builder.addPart("file[]", new FileBody(file)); } post.setEntity(builder.build()); try { response = httpclient.execute(post); String json = EntityUtils.toString(response.getEntity()); HttpPost repost = new HttpPost(this.getLink(json)); response = httpclient.execute(repost); String js = EntityUtils.toString(response.getEntity()); parseJson(js); System.out.println("Code : " + response.getStatusLine().getStatusCode()); if (response.getStatusLine().getStatusCode() != 200) { System.err.println("Error: POST not succesfull"); } else { } System.out.println(Configuration.getCurrent().getID()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public String[] getTechnologies() { String s[] = { "Storm", "Spark", "Hadoop Map-reduce" }; return s; } private void parseJson(String string) { JSONParser parser = new JSONParser(); try { JSONObject json = (JSONObject) parser.parse(string); JSONObject lin = (JSONObject) json.get("_links"); JSONObject sub = (JSONObject) lin.get("solution"); String link = (String) sub.get("href"); File f = new File(Preferences.getSavingDir() + "results"); if (!f.exists()) { try { PrintWriter writer = new PrintWriter(Preferences.getSavingDir() + "results", "UTF-8"); writer.println(Configuration.getCurrent().getID()); writer.println(link); writer.close(); } catch (IOException e) { // do something } } else { try (FileWriter fw = new FileWriter(Preferences.getSavingDir() + "results", true); BufferedWriter bw = new BufferedWriter(fw); PrintWriter out = new PrintWriter(bw)) { out.println(Configuration.getCurrent().getID()); // more code out.println(link); // more code } catch (IOException e) { // exception handling left as an exercise for the reader } } } catch (ParseException e) { // TODO Auto-generated catch block e.printStackTrace(); } } private String getLink(String string) { JSONParser parser = new JSONParser(); String link = ""; try { JSONObject json = (JSONObject) parser.parse(string); JSONObject lin = (JSONObject) json.get("_links"); JSONObject sub = (JSONObject) lin.get("submit"); link = (String) sub.get("href"); } catch (ParseException e) { // TODO Auto-generated catch block e.printStackTrace(); } return link; } }