Java tutorial
/* * RHQ Management Platform * Copyright (C) 2005-2008 Red Hat, Inc. * All rights reserved. * * 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.agent.promptcmd; import gnu.getopt.Getopt; import gnu.getopt.LongOpt; import java.beans.Introspector; import java.io.PrintWriter; import java.lang.management.ManagementFactory; import java.lang.management.MemoryMXBean; import java.lang.management.MemoryPoolMXBean; import java.lang.management.MemoryType; import java.lang.management.MemoryUsage; import java.util.List; import mazz.i18n.Msg; import org.apache.commons.logging.LogFactory; import org.rhq.enterprise.agent.AgentMain; import org.rhq.enterprise.agent.i18n.AgentI18NFactory; import org.rhq.enterprise.agent.i18n.AgentI18NResourceKeys; /** * Provides a way to help the agent clean up memory. * * @author John Mazzitelli */ public class GCPromptCommand implements AgentPromptCommand { private static final Msg MSG = AgentI18NFactory.getMsg(); /** * @see AgentPromptCommand#getPromptCommandString() */ public String getPromptCommandString() { return MSG.getMsg(AgentI18NResourceKeys.GC); } /** * @see AgentPromptCommand#execute(AgentMain, String[]) */ public boolean execute(AgentMain agent, String[] args) { processArguments(agent, args); return true; } /** * @see AgentPromptCommand#getSyntax() */ public String getSyntax() { return MSG.getMsg(AgentI18NResourceKeys.GC_SYNTAX); } /** * @see AgentPromptCommand#getHelp() */ public String getHelp() { return MSG.getMsg(AgentI18NResourceKeys.GC_HELP); } /** * @see AgentPromptCommand#getDetailedHelp() */ public String getDetailedHelp() { return MSG.getMsg(AgentI18NResourceKeys.GC_DETAILED_HELP); } private void processArguments(AgentMain agent, String[] args) { PrintWriter out = agent.getOut(); String sopts = "dfv:"; LongOpt[] lopts = { new LongOpt("verbose", LongOpt.REQUIRED_ARGUMENT, null, 'v'), new LongOpt("dump", LongOpt.NO_ARGUMENT, null, 'd'), new LongOpt("free", LongOpt.NO_ARGUMENT, null, 'f') }; Getopt getopt = new Getopt(getPromptCommandString(), args, sopts, lopts); int code; Boolean verbose = null; Boolean free = null; Boolean dump = null; while ((code = getopt.getopt()) != -1) { switch (code) { case ':': case '?': case 1: { out.println(MSG.getMsg(AgentI18NResourceKeys.HELP_SYNTAX_LABEL, getSyntax())); break; } case 'v': { String verboseOpt = getopt.getOptarg(); verbose = Boolean.valueOf(Boolean.parseBoolean(verboseOpt)); break; } case 'd': { dump = Boolean.TRUE; break; } case 'f': { free = Boolean.TRUE; break; } } } if ((getopt.getOptind() + 1) < args.length) { out.println(MSG.getMsg(AgentI18NResourceKeys.HELP_SYNTAX_LABEL, getSyntax())); } if (Boolean.TRUE.equals(dump)) { printCurrentMemoryUsage(out); } if (verbose != null) { setVerbosity(verbose.booleanValue()); } if (Boolean.TRUE.equals(free)) { freeMemory(out); } return; } private void setVerbosity(boolean verbose) { final MemoryMXBean memoryMxBean = ManagementFactory.getMemoryMXBean(); memoryMxBean.setVerbose(verbose); } private void freeMemory(PrintWriter out) { final MemoryMXBean memoryMxBean = ManagementFactory.getMemoryMXBean(); printGlobalMemoryUsage(out, memoryMxBean); // free up some global static caches Introspector.flushCaches(); LogFactory.releaseAll(); // invoke the garbage collector out.println(MSG.getMsg(AgentI18NResourceKeys.GC_INVOKE)); memoryMxBean.gc(); printGlobalMemoryUsage(out, memoryMxBean); return; } private void printCurrentMemoryUsage(PrintWriter out) { final MemoryMXBean memoryMxBean = ManagementFactory.getMemoryMXBean(); printGlobalMemoryUsage(out, memoryMxBean); List<MemoryPoolMXBean> poolMxBeans = ManagementFactory.getMemoryPoolMXBeans(); if (poolMxBeans != null) { for (MemoryPoolMXBean bean : poolMxBeans) { if (bean.isValid()) { String name = bean.getName(); MemoryType type = bean.getType(); MemoryUsage usage = bean.getUsage(); printMemoryUsage(out, name, type, usage); } } } return; } private void printGlobalMemoryUsage(PrintWriter out, final MemoryMXBean memoryMxBean) { printMemoryUsage(out, "GLOBAL", MemoryType.HEAP, memoryMxBean.getHeapMemoryUsage()); printMemoryUsage(out, "GLOBAL", MemoryType.NON_HEAP, memoryMxBean.getNonHeapMemoryUsage()); } private void printMemoryUsage(PrintWriter out, String name, MemoryType type, MemoryUsage memUsage) { long init = memUsage.getInit(); long max = memUsage.getMax(); long used = memUsage.getUsed(); long committed = memUsage.getCommitted(); String typeStr; switch (type) { case HEAP: typeStr = "Heap"; break; case NON_HEAP: typeStr = "Non-heap"; break; default: typeStr = "?"; } double usedPercentage = (used * 100.0) / committed; double committedPercentage = (committed * 100.0) / max; out.println(MSG.getMsg(AgentI18NResourceKeys.GC_MEM_USAGE, name, typeStr, init, max, used, usedPercentage, committed, committedPercentage)); } }