Java tutorial
/* * RHQ Management Platform * Copyright 2014, Red Hat Middleware LLC, and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ package org.rhq.enterprise.server.plugins.jdr; import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.InetAddress; import java.net.ServerSocket; import java.net.Socket; import java.net.SocketException; import java.net.SocketTimeoutException; import java.util.Map; import java.util.UUID; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.ObjectWriter; import org.rhq.enterprise.server.plugin.pc.ServerPluginComponent; import org.rhq.enterprise.server.plugin.pc.ServerPluginContext; import org.rhq.enterprise.server.system.SystemInfoManagerLocal; import org.rhq.enterprise.server.util.LookupUtil; public class JdrServerPluginComponent implements ServerPluginComponent { private UUID accessToken; private static final Log log = LogFactory.getLog(JdrServerPluginComponent.class); private static final int LISTEN = 7079; private static final int SOCK_TIMEOUT = 5 * 1000; private static final String TOKEN_FILE_NAME = "jdr-token"; private static final int TOKEN_SIZE = UUID.randomUUID().toString().length(); private static final Object lock = new Object(); private Thread serverThread; private ServerSocket server; @Override public void initialize(ServerPluginContext context) throws Exception { setAccessToken(); log.debug("Plugin initialized"); } private void setAccessToken() { synchronized (lock) { accessToken = UUID.randomUUID(); writeAccessToken(); } } private String getAccessToken() { synchronized (lock) { return accessToken.toString(); } } private void writeAccessToken() { File dataDir = new File(System.getProperty("jboss.server.data.dir")); if (!dataDir.exists() || !dataDir.canWrite()) { log.error("Failed to write access token, jboss.server.data.dir=" + dataDir + " does not exist or not writable"); return; } File file = new File(dataDir, TOKEN_FILE_NAME); try { PrintWriter pw = new PrintWriter(file); pw.println(accessToken); pw.close(); file.setWritable(true, true); file.setReadable(true, true); file.setExecutable(false, false); boolean isWindows = (File.separatorChar == '\\'); if (!isWindows) { try { Runtime.getRuntime().exec("chmod 600 " + file.getAbsolutePath()); } catch (IOException e) { log.error("Unable to set file permissions", e); } } } catch (FileNotFoundException fnfe) { log.error("Failed to write acces token, jboss.server.data.dir=" + file.getParent() + " does not exist or not writable"); } } @Override public void start() { try { server = new ServerSocket(LISTEN, 1, InetAddress.getByName(null)); serverThread = new Thread(new Runnable() { @Override public void run() { try { log.debug("Listening on " + LISTEN); while (true) { Socket socket = server.accept(); socket.setSoTimeout(SOCK_TIMEOUT); log.debug("Connection successfull"); PrintWriter out = new PrintWriter(socket.getOutputStream(), true); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); String inputLine = null; try { char[] buffer = new char[TOKEN_SIZE]; int read = in.read(buffer); if (read == TOKEN_SIZE) { inputLine = new String(buffer); if (inputLine.equals(getAccessToken())) { log.debug("Client authorized"); out.println(getSystemInfo()); log.debug("SystemInfo returned"); setAccessToken(); // regenerate } else { log.debug("Invalid token recieved"); out.println("Bye!"); } } else { log.debug("Invalid token recieved"); out.println("Bye!"); } } catch (SocketTimeoutException ex) { log.debug("Client timed out to send token"); out.println("Bye!"); } in.close(); out.close(); socket.close(); } } catch (SocketException e) { // listening was canceled } catch (Exception e) { log.error("Socket server interrupted", e); } } }); serverThread.start(); } catch (Exception ex) { log.error(ex); } } private String getSystemInfo() { try { SystemInfoManagerLocal mgr = LookupUtil.getSystemInfoManager(); Map<String, String> systemInfo = mgr.getSystemInformation(LookupUtil.getSubjectManager().getOverlord()); final ObjectWriter writer = new ObjectMapper().writerWithDefaultPrettyPrinter(); return writer.writeValueAsString(systemInfo); } catch (Exception e) { log.error(e); return "ERROR retrieving system info : " + e.getMessage(); } } @Override public void stop() { if (serverThread != null) { serverThread.interrupt(); } if (server != null) { try { if (!server.isClosed()) { server.close(); log.debug("Socket server closed"); } } catch (Exception e) { log.error(e); } } } @Override public void shutdown() { stop(); } }