Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.hadoop.chukwa.hicc; import java.io.*; import java.nio.charset.Charset; import java.util.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.chukwa.util.XssFilter; import org.json.simple.JSONArray; import org.json.simple.JSONObject; import org.json.simple.JSONValue; import org.apache.hadoop.chukwa.util.ExceptionUtil; public class Workspace extends HttpServlet { public static final long serialVersionUID = 101L; private static final Log log = LogFactory.getLog(Workspace.class); private String path = System.getenv("CHUKWA_DATA_DIR"); private JSONObject hash = new JSONObject(); transient private XssFilter xf; @Override protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { xf = new XssFilter(request); response.setContentType("text/plain"); String method = xf.getParameter("method"); if (method.equals("get_views_list")) { getViewsList(request, response); } if (method.equals("get_view")) { getView(request, response); } if (method.equals("save_view")) { saveView(request, response); } if (method.equals("change_view_info")) { changeViewInfo(request, response); } if (method.equals("get_widget_list")) { getWidgetList(request, response); } if (method.equals("clone_view")) { cloneView(request, response); } if (method.equals("delete_view")) { deleteView(request, response); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { doGet(request, response); } static public String getContents(File aFile) { // ...checks on aFile are elided StringBuffer contents = new StringBuffer(); try { // use buffering, reading one line at a time // FileReader always assumes default encoding is OK! BufferedReader input = new BufferedReader( new InputStreamReader(new FileInputStream(aFile.getAbsolutePath()), Charset.forName("UTF-8"))); try { String line = null; // not declared within while loop /* * readLine is a bit quirky : it returns the content of a line MINUS the * newline. it returns null only for the END of the stream. it returns * an empty String if two newlines appear in a row. */ while ((line = input.readLine()) != null) { contents.append(line); contents.append(System.getProperty("line.separator")); } } finally { input.close(); } } catch (IOException ex) { ex.printStackTrace(); } return contents.toString(); } public void setContents(String fName, String buffer) { try { BufferedWriter out = new BufferedWriter( new OutputStreamWriter(new FileOutputStream(fName), Charset.forName("UTF-8"))); out.write(buffer); out.close(); } catch (Exception e) { System.err.println("Error: " + e.getMessage()); } } public void cloneView(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); String name = xf.getParameter("name"); String template = xf.getParameter("clone_name"); File aFile = new File(path + "/views/" + template); String config = getContents(aFile); int i = 0; boolean check = true; while (check) { String tmpName = name; if (i > 0) { tmpName = name + i; } File checkFile = new File(path + "/views/" + tmpName + ".view"); check = checkFile.exists(); if (!check) { name = tmpName; } i = i + 1; } setContents(path + "/views/" + name + ".view", config); File deleteCache = new File(path + "/views/workspace_view_list.cache"); if (!deleteCache.delete()) { log.warn("Can not delete " + path + "/views/workspace_view_list.cache"); } genViewCache(path + "/views"); aFile = new File(path + "/views/workspace_view_list.cache"); String viewsCache = getContents(aFile); out.println(viewsCache); } public void deleteView(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String name = xf.getParameter("name"); File aFile = new File(path + "/views/" + name + ".view"); if (!aFile.delete()) { log.warn("Can not delete " + path + "/views/" + name + ".view"); } File deleteCache = new File(path + "/views/workspace_view_list.cache"); if (!deleteCache.delete()) { log.warn("Can not delete " + path + "/views/workspace_view_list.cache"); } genViewCache(path + "/views"); } public void getViewsList(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); genViewCache(path + "/views"); File aFile = new File(path + "/views/workspace_view_list.cache"); String viewsCache = getContents(aFile); out.println(viewsCache); } public void getView(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); String id = xf.getParameter("id"); genViewCache(path + "/views"); File aFile = new File(path + "/views/" + id + ".view"); String view = getContents(aFile); out.println(view); } public void changeViewInfo(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); String id = xf.getParameter("name"); String config = request.getParameter("config"); try { JSONObject jt = (JSONObject) JSONValue.parse(config); File aFile = new File(path + "/views/" + id + ".view"); String original = getContents(aFile); JSONObject updateObject = (JSONObject) JSONValue.parse(original); updateObject.put("description", jt.get("description")); setContents(path + "/views/" + id + ".view", updateObject.toString()); if (!rename(id, jt.get("description").toString())) { throw new Exception("Rename view file failed"); } File deleteCache = new File(path + "/views/workspace_view_list.cache"); if (!deleteCache.delete()) { log.warn("Can not delete " + path + "/views/workspace_view_list.cache"); } genViewCache(path + "/views"); out.println("Workspace is stored successfully."); } catch (Exception e) { out.println("Workspace store failed."); } } public void saveView(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); String id = xf.getParameter("name"); String config = request.getParameter("config"); setContents(path + "/views/" + id + ".view", config); out.println("Workspace is stored successfully."); } public void getWidgetList(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { PrintWriter out = response.getWriter(); genWidgetCache(path + "/descriptors"); File aFile = new File(path + "/descriptors/workspace_plugin.cache"); String viewsCache = getContents(aFile); out.println(viewsCache); } private void genViewCache(String source) { File cacheFile = new File(source + "/workspace_view_list.cache"); if (!cacheFile.exists()) { File dir = new File(source); File[] filesWanted = dir.listFiles(new FilenameFilter() { public boolean accept(File dir, String name) { return name.endsWith(".view"); } }); if (filesWanted != null) { JSONObject[] cacheGroup = new JSONObject[filesWanted.length]; for (int i = 0; i < filesWanted.length; i++) { String buffer = getContents(filesWanted[i]); try { JSONObject jt = (JSONObject) JSONValue.parse(buffer); String fn = filesWanted[i].getName(); jt.put("key", fn.substring(0, (fn.length() - 5))); cacheGroup[i] = jt; } catch (Exception e) { log.debug(ExceptionUtil.getStackTrace(e)); } } String viewList = convertObjectsToViewList(cacheGroup); setContents(source + "/workspace_view_list.cache", viewList); } } } public String convertObjectsToViewList(JSONObject[] objArray) { JSONArray jsonArr = new JSONArray(); JSONObject permission = new JSONObject(); JSONObject user = new JSONObject(); try { permission.put("read", 1); permission.put("modify", 1); user.put("all", permission); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } for (int i = 0; i < objArray.length; i++) { try { JSONObject jsonObj = new JSONObject(); jsonObj.put("key", objArray[i].get("key")); jsonObj.put("description", objArray[i].get("description")); jsonObj.put("owner", ""); jsonObj.put("permission", user); jsonArr.add(jsonObj); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } } return jsonArr.toString(); } private void genWidgetCache(String source) { File cacheFile = new File(source + "/workspace_plugin.cache"); File cacheDir = new File(source); if (!cacheFile.exists() || cacheFile.lastModified() < cacheDir.lastModified()) { File dir = new File(source); File[] filesWanted = dir.listFiles(new FilenameFilter() { public boolean accept(File dir, String name) { return name.endsWith(".descriptor"); } }); if (filesWanted != null) { JSONObject[] cacheGroup = new JSONObject[filesWanted.length]; for (int i = 0; i < filesWanted.length; i++) { String buffer = getContents(filesWanted[i]); try { JSONObject jt = (JSONObject) JSONValue.parse(buffer); cacheGroup[i] = jt; } catch (Exception e) { log.debug(ExceptionUtil.getStackTrace(e)); } } String widgetList = convertObjectsToWidgetList(cacheGroup); setContents(source + "/workspace_plugin.cache", widgetList); } } } public String convertObjectsToWidgetList(JSONObject[] objArray) { JSONObject jsonObj = new JSONObject(); JSONArray jsonArr = new JSONArray(); for (int i = 0; i < objArray.length; i++) { jsonArr.add(objArray[i]); } try { jsonObj.put("detail", jsonArr); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } for (int i = 0; i < objArray.length; i++) { try { String[] categoriesArray = objArray[i].get("categories").toString().split(","); hash = addToHash(hash, categoriesArray, objArray[i]); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } } try { jsonObj.put("children", hash); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } return jsonObj.toString(); } public JSONObject addToHash(JSONObject hash, String[] categoriesArray, JSONObject obj) { JSONObject subHash = hash; for (int i = 0; i < categoriesArray.length; i++) { String id = categoriesArray[i]; if (i >= categoriesArray.length - 1) { try { subHash.put("leaf:" + obj.get("title"), obj.get("id")); } catch (Exception e) { System.err.println("JSON Exception: " + e.getMessage()); } } else { try { subHash = (JSONObject) subHash.get("node:" + id); } catch (Exception e) { try { JSONObject tmpHash = new JSONObject(); subHash.put("node:" + id, tmpHash); subHash = tmpHash; } catch (Exception ex) { log.debug(ExceptionUtil.getStackTrace(e)); } } } } return hash; } private boolean rename(String id, String desc) { try { File view = new File(path + "/views/" + id + ".view"); File newFile = new File(path + File.separator + "views" + File.separator + desc + ".view"); if (!view.renameTo(newFile)) { log.warn("Can not rename " + path + "/views/" + id + ".view to " + path + File.separator + "views" + File.separator + desc + ".view"); } } catch (Exception e) { return false; } return true; } }