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 * 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

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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(

                                    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(

                                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(

                            PerfDataFile.getLocalVmId(files[j]));

                }

            }

        }

        return jvmSet;

    }

}