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.felix.webconsole.internal.system; import java.io.IOException; import java.text.DateFormat; import java.text.MessageFormat; import java.util.Date; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.felix.webconsole.DefaultVariableResolver; import org.apache.felix.webconsole.SimpleWebConsolePlugin; import org.apache.felix.webconsole.WebConsoleUtil; import org.apache.felix.webconsole.internal.OsgiManagerPlugin; import org.json.JSONException; import org.json.JSONObject; import org.osgi.framework.Bundle; import org.osgi.framework.BundleException; import org.osgi.service.startlevel.StartLevel; /** * VMStatPlugin provides the System Information tab. This particular plugin uses * more than one templates. */ public class VMStatPlugin extends SimpleWebConsolePlugin implements OsgiManagerPlugin { private static final String LABEL = "vmstat"; private static final String TITLE = "%vmstat.pluginTitle"; private static final String CSS[] = null; private static final String ATTR_TERMINATED = "terminated"; private static final String PARAM_SHUTDOWN_TIMER = "shutdown_timer"; private static final String PARAM_SHUTDOWN_TYPE = "shutdown_type"; private static final String PARAM_SHUTDOWN_TYPE_RESTART = "Restart"; //private static final String PARAM_SHUTDOWN_TYPE_STOP = "Stop"; private static final long startDate = System.currentTimeMillis(); // from BaseWebConsolePlugin private static String START_LEVEL_NAME = StartLevel.class.getName(); // templates private final String TPL_VM_MAIN; private final String TPL_VM_STOP; private final String TPL_VM_RESTART; /** Default constructor */ public VMStatPlugin() { super(LABEL, TITLE, CSS); // load templates TPL_VM_MAIN = readTemplateFile("/templates/vmstat.html"); TPL_VM_STOP = readTemplateFile("/templates/vmstat_stop.html"); TPL_VM_RESTART = readTemplateFile("/templates/vmstat_restart.html"); } /** * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { final String action = request.getParameter("action"); if ("setStartLevel".equals(action)) { StartLevel sl = getStartLevel(); if (sl != null) { int bundleSL = WebConsoleUtil.getParameterInt(request, "bundleStartLevel", -1); if (bundleSL > 0 && bundleSL != sl.getInitialBundleStartLevel()) { sl.setInitialBundleStartLevel(bundleSL); } int systemSL = WebConsoleUtil.getParameterInt(request, "systemStartLevel", -1); if (systemSL > 0 && systemSL != sl.getStartLevel()) { sl.setStartLevel(systemSL); } } } else if ("gc".equals(action)) { System.gc(); System.gc(); // twice for sure } else if (request.getParameter(PARAM_SHUTDOWN_TIMER) == null) { // whether to stop or restart the framework final boolean restart = PARAM_SHUTDOWN_TYPE_RESTART.equals(request.getParameter(PARAM_SHUTDOWN_TYPE)); // simply terminate VM in case of shutdown :-) final Bundle systemBundle = getBundleContext().getBundle(0); Thread t = new Thread("Stopper") { public void run() { try { Thread.sleep(2000L); } catch (InterruptedException ie) { // ignore } log("Shutting down server now!"); // stopping bundle 0 (system bundle) stops the framework try { if (restart) { systemBundle.update(); } else { systemBundle.stop(); } } catch (BundleException be) { log("Problem stopping or restarting the Framework", be); } } }; t.start(); request.setAttribute(ATTR_TERMINATED, ATTR_TERMINATED); request.setAttribute(PARAM_SHUTDOWN_TYPE, new Boolean(restart)); } // render the response without redirecting doGet(request, response); } /** * @see org.apache.felix.webconsole.AbstractWebConsolePlugin#renderContent(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ protected void renderContent(HttpServletRequest request, HttpServletResponse response) throws IOException { String body; if (request.getAttribute(ATTR_TERMINATED) != null) { Object restart = request.getAttribute(PARAM_SHUTDOWN_TYPE); if ((restart instanceof Boolean) && ((Boolean) restart).booleanValue()) { body = TPL_VM_RESTART; } else { body = TPL_VM_STOP; } response.getWriter().print(body); return; } body = TPL_VM_MAIN; long freeMem = Runtime.getRuntime().freeMemory() / 1024; long totalMem = Runtime.getRuntime().totalMemory() / 1024; long usedMem = totalMem - freeMem; boolean shutdownTimer = request.getParameter(PARAM_SHUTDOWN_TIMER) != null; String shutdownType = request.getParameter(PARAM_SHUTDOWN_TYPE); if (shutdownType == null) shutdownType = ""; DateFormat format = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, request.getLocale()); final String startTime = format.format(new Date(startDate)); final String upTime = formatPeriod(System.currentTimeMillis() - startDate); JSONObject json = new JSONObject(); try { json.put("systemStartLevel", getStartLevel().getStartLevel()); json.put("bundleStartLevel", getStartLevel().getInitialBundleStartLevel()); json.put("lastStarted", startTime); json.put("upTime", upTime); json.put("runtime", System.getProperty("java.runtime.name") + "(build " + System.getProperty("java.runtime.version") + ")"); json.put("jvm", System.getProperty("java.vm.name") + "(build " + System.getProperty("java.vm.version") + ", " + System.getProperty("java.vm.info") + ")"); json.put("shutdownTimer", shutdownTimer); json.put("mem_total", totalMem); json.put("mem_free", freeMem); json.put("mem_used", usedMem); json.put("shutdownType", shutdownType); // only add the processors if the number is available final int processors = getAvailableProcessors(); if (processors > 0) { json.put("processors", processors); } } catch (JSONException e) { throw new IOException(e.toString()); } DefaultVariableResolver vars = ((DefaultVariableResolver) WebConsoleUtil.getVariableResolver(request)); vars.put("startData", json.toString()); response.getWriter().print(body); } private String formatPeriod(final long period) { final Long msecs = new Long(period % 1000); final Long secs = new Long(period / 1000 % 60); final Long mins = new Long(period / 1000 / 60 % 60); final Long hours = new Long(period / 1000 / 60 / 60 % 24); final Long days = new Long(period / 1000 / 60 / 60 / 24); return MessageFormat.format( "{0,number} '${vmstat.upTime.format.days}' {1,number,00}:{2,number,00}:{3,number,00}.{4,number,000}", new Object[] { days, hours, mins, secs, msecs }); } private final StartLevel getStartLevel() { return (StartLevel) getService(START_LEVEL_NAME); } /** * Returns the number of processor available on Java 1.4 and newer runtimes. * If the Runtime.availableProcessors() method is not available, this * method returns -1. */ private int getAvailableProcessors() { try { return Runtime.getRuntime().availableProcessors(); } catch (Throwable t) { // NoSuchMethodError on pre-1.4 runtimes } return -1; } }