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	/*
	* Copyright (c) 2004, 2007, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.jvmstat.perfdata.monitor.protocol.local;

	import sun.jvmstat.monitor.*;
	import sun.jvmstat.monitor.event.*;
	import java.util.*;
	import java.util.regex.*;
	import java.io.*;

	/**
	* Class for managing the LocalMonitoredVm instances on the local system.
	* <p>
	* This class is responsible for the mechanism that detects the active
	* HotSpot Java Virtual Machines on the local host and possibly for a
	* specific user. The ability to detect all possible HotSpot Java Virtual
	* Machines on the local host may be limited by the permissions of the
	* principal running this JVM.
	*
	* @author Brian Doherty
	* @since 1.5
	*/
	public class LocalVmManager {
	private String userName; // user name for monitored jvm
	private File tmpdir;
	private Pattern userPattern;
	private Matcher userMatcher;
	private FilenameFilter userFilter;
	private Pattern filePattern;
	private Matcher fileMatcher;
	private FilenameFilter fileFilter;
	private Pattern tmpFilePattern;
	private Matcher tmpFileMatcher;
	private FilenameFilter tmpFileFilter;

	/**
	* Creates a LocalVmManager instance for the local system.
	* <p>
	* Manages LocalMonitoredVm instances for which the principal
	* has appropriate permissions.
	*/
	public LocalVmManager() {
	this(null);
	}

	/**
	* Creates a LocalVmManager instance for the given user.
	* <p>
	* Manages LocalMonitoredVm instances for all JVMs owned by the specified
	* user.
	*
	* @param user the name of the user
	*/
	public LocalVmManager(String user) {
	this.userName = user;

	if (userName == null) {
	tmpdir = new File(PerfDataFile.getTempDirectory());
	userPattern = Pattern.compile(PerfDataFile.userDirNamePattern);
	userMatcher = userPattern.matcher("");

	userFilter = new FilenameFilter() {
	public boolean accept(File dir, String name) {
	userMatcher.reset(name);
	return userMatcher.lookingAt();
	}
	};
	} else {
	tmpdir = new File(PerfDataFile.getTempDirectory(userName));
	}

	filePattern = Pattern.compile(PerfDataFile.fileNamePattern);
	fileMatcher = filePattern.matcher("");

	fileFilter = new FilenameFilter() {
	public boolean accept(File dir, String name) {
	fileMatcher.reset(name);
	return fileMatcher.matches();
	}
	};

	tmpFilePattern = Pattern.compile(PerfDataFile.tmpFileNamePattern);
	tmpFileMatcher = tmpFilePattern.matcher("");

	tmpFileFilter = new FilenameFilter() {
	public boolean accept(File dir, String name) {
	tmpFileMatcher.reset(name);
	return tmpFileMatcher.matches();
	}
	};
	}

	/**
	* Return the current set of monitorable Java Virtual Machines.
	* <p>
	* The set returned by this method depends on the user name passed
	* to the constructor. If no user name was specified, then this
	* method will return all candidate JVMs on the system. Otherwise,
	* only the JVMs for the given user will be returned. This assumes
	* that principal associated with this JVM has the appropriate
	* permissions to access the target set of JVMs.
	*
	* @return Set - the Set of monitorable Java Virtual Machines
	*/
	public synchronized Set<Integer> activeVms() {
	/*
	* This method is synchronized because the Matcher object used by
	* fileFilter is not safe for concurrent use, and this method is
	* called by multiple threads. Before this method was synchronized,
	* we'd see strange file names being matched by the matcher.
	*/
	Set<Integer> jvmSet = new HashSet<Integer>();

	if (! tmpdir.isDirectory()) {
	return jvmSet;
	}

	if (userName == null) {
	/*
	* get a list of all of the user temporary directories and
	* iterate over the list to find any files within those directories.
	*/
	File[] dirs = tmpdir.listFiles(userFilter);

	for (int i = 0 ; i < dirs.length; i ++) {
	if (!dirs[i].isDirectory()) {
	continue;
	}

	// get a list of files from the directory
	File[] files = dirs[i].listFiles(fileFilter);

	if (files != null) {
	for (int j = 0; j < files.length; j++) {
	if (files[j].isFile() && files[j].canRead()) {
	jvmSet.add(new Integer(
	PerfDataFile.getLocalVmId(files[j])));
	}
	}
	}
	}
	} else {
	/*
	* Check if the user directory can be accessed. Any of these
	* conditions may have asynchronously changed between subsequent
	* calls to this method.
	*/

	// get the list of files from the specified user directory
	File[] files = tmpdir.listFiles(fileFilter);

	if (files != null) {
	for (int j = 0; j < files.length; j++) {
	if (files[j].isFile() && files[j].canRead()) {
	jvmSet.add(new Integer(
	PerfDataFile.getLocalVmId(files[j])));
	}
	}
	}
	}

	// look for any 1.4.1 files
	File[] files = tmpdir.listFiles(tmpFileFilter);
	if (files != null) {
	for (int j = 0; j < files.length; j++) {
	if (files[j].isFile() && files[j].canRead()) {
	jvmSet.add(new Integer(
	PerfDataFile.getLocalVmId(files[j])));
	}
	}
	}

	return jvmSet;
	}
	}

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