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.plugins.platform; import java.beans.Introspector; import java.beans.PropertyDescriptor; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStreamReader; import java.util.List; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.rhq.core.domain.configuration.Configuration; import org.rhq.core.domain.measurement.AvailabilityType; import org.rhq.core.domain.measurement.MeasurementDataNumeric; import org.rhq.core.domain.measurement.MeasurementReport; import org.rhq.core.domain.measurement.MeasurementScheduleRequest; import org.rhq.core.pluginapi.inventory.InvalidPluginConfigurationException; import org.rhq.core.pluginapi.inventory.ResourceComponent; import org.rhq.core.pluginapi.inventory.ResourceContext; import org.rhq.core.pluginapi.measurement.MeasurementFacet; import org.rhq.core.system.AggregateProcessInfo; import org.rhq.core.system.ProcessInfo; import org.rhq.core.system.SystemInfo; import org.rhq.core.util.exception.ThrowableUtil; /** * Monitors a generic process. * * @author Greg Hinkle * @author John Mazzitelli */ public class ProcessComponent implements ResourceComponent, MeasurementFacet { private static final Log log = LogFactory.getLog(ProcessComponent.class); private enum Type { pidFile, piql } private ResourceContext resourceContext; private ProcessInfo process; private Type type; private String pidFile; private String piql; private boolean fullProcessTree; public void start(ResourceContext resourceContext) throws InvalidPluginConfigurationException, Exception { this.resourceContext = resourceContext; try { Configuration config = this.resourceContext.getPluginConfiguration(); this.type = Type.valueOf(config.getSimpleValue("type", "pidFile")); this.pidFile = config.getSimpleValue("pidFile", null); this.piql = config.getSimpleValue("piql", null); this.fullProcessTree = config.getSimple("fullProcessTree").getBooleanValue(); } catch (Exception e) { throw new InvalidPluginConfigurationException(e); } // validate the plugin config some more if (this.type == Type.pidFile && (this.pidFile == null || this.pidFile.length() == 0)) { throw new InvalidPluginConfigurationException("Missing pidfile"); } if (this.type == Type.piql && (this.piql == null || this.piql.length() == 0)) { throw new InvalidPluginConfigurationException("Missing process query"); } } public void stop() { } public AvailabilityType getAvailability() { try { return getProcess().isRunning() ? AvailabilityType.UP : AvailabilityType.DOWN; } catch (Exception e) { if (log.isDebugEnabled()) { log.debug("failed to get process info: " + ThrowableUtil.getAllMessages(e)); } return AvailabilityType.DOWN; } } private ProcessInfo getProcess() throws Exception { if (this.process == null || !this.process.isRunning()) { this.process = getProcessForConfiguration(); } return this.process; } private ProcessInfo getProcessForConfiguration() throws Exception { SystemInfo sysInfo = this.resourceContext.getSystemInformation(); return getProcessForConfiguration(this.type, this.pidFile, this.piql, this.fullProcessTree, sysInfo); } protected static ProcessInfo getProcessForConfiguration(Configuration config, SystemInfo systemInfo) throws Exception { Type type = Type.valueOf(config.getSimpleValue("type", "pidFile")); String pidFile = config.getSimpleValue("pidFile", null); String piql = config.getSimpleValue("piql", null); boolean fullProcessTree = config.getSimple("fullProcessTree").getBooleanValue(); return getProcessForConfiguration(type, pidFile, piql, fullProcessTree, systemInfo); } private static ProcessInfo getProcessForConfiguration(Type type, String pidFile, String piql, boolean fullProcessTree, SystemInfo systemInfo) throws Exception { long pid; if (type == Type.pidFile) { File file = new File(pidFile); if (file.canRead()) { FileInputStream fis = new FileInputStream(file); try { BufferedReader r = new BufferedReader(new InputStreamReader(fis)); pid = Long.parseLong(r.readLine()); } finally { try { fis.close(); } catch (Exception ignore) { } } } else { throw new FileNotFoundException("pidfile [" + pidFile + "] does not exist or is not allowed to be read. full path=" + file.getAbsolutePath()); } } else if (type == Type.piql) { List<ProcessInfo> processes = systemInfo.getProcesses(piql); if (processes != null && processes.size() == 1) { pid = processes.get(0).getPid(); } else { throw new Exception("process query [" + piql + "] did not return a single process: " + processes); } } else { throw new InvalidPluginConfigurationException("Invalid type [" + type + "]"); } ProcessInfo processInfo; if (fullProcessTree) { processInfo = new AggregateProcessInfo(pid); } else { processInfo = new ProcessInfo(pid); } return processInfo; } public void getValues(MeasurementReport report, Set<MeasurementScheduleRequest> metrics) { if (this.process != null) { this.process.refresh(); for (MeasurementScheduleRequest request : metrics) { String propertyName = request.getName(); if (propertyName.startsWith("Process.")) { propertyName = convertPropertyName(propertyName, this.process); Object val = lookupAttributeProperty(this.process, propertyName.substring("Process.".length())); if (val != null && val instanceof Number) { report.addData(new MeasurementDataNumeric(request, ((Number) val).doubleValue())); } } } } return; } private String convertPropertyName(String propertyName, ProcessInfo theProcess) { // if its an aggregate process info, the bean property name is different if (theProcess instanceof AggregateProcessInfo) { propertyName = propertyName.replace(".cpu.", ".aggregateCpu."); propertyName = propertyName.replace(".memory.", ".aggregateMemory."); propertyName = propertyName.replace(".fileDescriptor.", ".aggregateFileDescriptor."); } return propertyName; } private Object lookupAttributeProperty(Object value, String property) { String[] ps = property.split("\\.", 2); String searchProperty = ps[0]; // Try to use reflection try { PropertyDescriptor[] pds = Introspector.getBeanInfo(value.getClass()).getPropertyDescriptors(); for (PropertyDescriptor pd : pds) { if (pd.getName().equals(searchProperty)) { value = pd.getReadMethod().invoke(value); break; } } } catch (Exception e) { if (log.isDebugEnabled()) { log.debug("Unable to read property [" + property + "]; measurement attribute [" + searchProperty + "] not found on [" + this.resourceContext.getResourceKey() + "]. Cause: " + e); } } if (ps.length > 1) { value = lookupAttributeProperty(value, ps[1]); } return value; } }