Back to index...

	/*
	* Copyright (c) 2004, 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 java.io.File;
	import java.io.FilenameFilter;

	/**
	* Class to provide translations from the local Vm Identifier
	* name space into the file system name space and vice-versa.
	* <p>
	* Provides a factory for creating a File object to the backing
	* store file for instrumentation shared memory region for a JVM
	* identified by its Local Java Virtual Machine Identifier, or
	* <em>lvmid</em>.
	*
	* @author Brian Doherty
	* @since 1.5
	* @see java.io.File
	*/
	public class PerfDataFile {
	private PerfDataFile() { };

	/**
	* The name of the of the system dependent temporary directory
	*/
	public static final String tmpDirName;

	/**
	* The file name prefix for PerfData shared memory files.
	* <p>
	* This prefix must be kept in sync with the prefix used by the JVM.
	*/
	public static final String dirNamePrefix = "hsperfdata_";

	/**
	* The directory name pattern for the user directories.
	*/
	public static final String userDirNamePattern = "hsperfdata_\\S*";

	/**
	* The file name pattern for PerfData shared memory files.
	* <p>
	* This pattern must be kept in synch with the file name pattern
	* used by the 1.4.2 and later HotSpot JVM.
	*/
	public static final String fileNamePattern = "^[0-9]+$";

	/**
	* The file name pattern for 1.4.1 PerfData shared memory files.
	* <p>
	* This pattern must be kept in synch with the file name pattern
	* used by the 1.4.1 HotSpot JVM.
	*/
	public static final String tmpFileNamePattern =
	"^hsperfdata_[0-9]+(_[1-2]+)?$";


	/**
	* Get a File object for the instrumentation backing store file
	* for the JVM identified by the given local Vm Identifier.
	* <p>
	* This method looks for the most up to date backing store file for
	* the given <tt>lvmid</tt>. It will search all the user specific
	* directories in the temporary directory for the host operating
	* system, which may be influenced by platform specific environment
	* variables.
	*
	* @param lvmid the local Java Virtual Machine Identifier for the target
	* @return File - a File object to the backing store file for the named
	* shared memory region of the target JVM.
	* @see java.io.File
	* @see #getTempDirectory()
	*/
	public static File getFile(int lvmid) {
	if (lvmid == 0) {
	/*
	* lvmid == 0 is used to indicate the current Java Virtual Machine.
	* If the SDK provided an API to get a unique Java Virtual Machine
	* identifier, then a filename could be constructed with that
	* identifier. In absence of such an api, return null.
	*/
	return null;
	}

	/*
	* iterate over all files in all directories in tmpDirName that
	* match the file name patterns.
	*/
	File tmpDir = new File(tmpDirName);
	String[] files = tmpDir.list(new FilenameFilter() {
	public boolean accept(File dir, String name) {
	if (!name.startsWith(dirNamePrefix)) {
	return false;
	}
	File candidate = new File(dir, name);
	return ((candidate.isDirectory() \|\| candidate.isFile())
	&& candidate.canRead());
	}
	});

	long newestTime = 0;
	File newest = null;

	for (int i = 0; i < files.length; i++) {
	File f = new File(tmpDirName + files[i]);
	File candidate = null;

	if (f.exists() && f.isDirectory()) {
	/*
	* found a directory matching the name patterns. This
	* is a 1.4.2 hsperfdata_<user> directory. Check for
	* file named <lvmid> in that directory
	*/
	String name = Integer.toString(lvmid);
	candidate = new File(f.getName(), name);

	} else if (f.exists() && f.isFile()) {
	/*
	* found a file matching the name patterns. This
	* is a 1.4.1 hsperfdata_<lvmid> file.
	*/
	candidate = f;

	} else {
	// unexpected - let conditional below filter this one out
	candidate = f;
	}

	if (candidate.exists() && candidate.isFile()
	&& candidate.canRead()) {
	long modTime = candidate.lastModified();
	if (modTime >= newestTime) {
	newestTime = modTime;
	newest = candidate;
	}
	}
	}
	return newest;
	}

	/**
	* Return the File object for the backing store file for the specified Java
	* Virtual Machine.
	* <p>
	* This method looks for the most up to date backing store file for
	* the JVM identified by the given user name and lvmid. The directory
	* searched is the temporary directory for the host operating system,
	* which may be influenced by environment variables.
	*
	* @param user the user name
	* @param lvmid the local Java Virtual Machine Identifier for the target
	* @return File - a File object to the backing store file for the named
	* shared memory region of the target JVM.
	* @see java.io.File
	* @see #getTempDirectory()
	*/
	public static File getFile(String user, int lvmid) {
	if (lvmid == 0) {
	/*
	* lvmid == 0 is used to indicate the current Java Virtual Machine.
	* If the SDK provided an API to get a unique Java Virtual Machine
	* identifier, then a filename could be constructed with that
	* identifier. In absence of such an api, return null.
	*/
	return null;
	}

	// first try for 1.4.2 and later JVMs
	String basename = getTempDirectory(user) + Integer.toString(lvmid);
	File f = new File(basename);

	if (f.exists() && f.isFile() && f.canRead()) {
	return f;
	}

	// No hit on 1.4.2 JVMs, try 1.4.1 files
	long newestTime = 0;
	File newest = null;
	for (int i = 0; i < 2; i++) {
	if (i == 0) {
	basename = getTempDirectory() + Integer.toString(lvmid);
	} else {
	basename = getTempDirectory() + Integer.toString(lvmid)
	+ Integer.toString(i);
	}

	f = new File(basename);

	if (f.exists() && f.isFile() && f.canRead()) {
	long modTime = f.lastModified();
	if (modTime >= newestTime) {
	newestTime = modTime;
	newest = f;
	}
	}
	}
	return newest;
	}

	/**
	* Method to extract a local Java Virtual Machine Identifier from the
	* file name of the given File object.
	*
	* @param file A File object representing the name of a
	* shared memory region for a target JVM
	* @return int - the local Java Virtual Machine Identifier for the target
	* associated with the file
	* @throws java.lang.IllegalArgumentException Thrown if the file name
	* does not conform to the expected pattern
	*/
	public static int getLocalVmId(File file) {
	try {
	// try 1.4.2 and later format first
	return Integer.parseInt(file.getName());
	} catch (NumberFormatException e) { }

	// now try the 1.4.1 format
	String name = file.getName();
	if (name.startsWith(dirNamePrefix)) {
	int first = name.indexOf('_');
	int last = name.lastIndexOf('_');
	try {
	if (first == last) {
	return Integer.parseInt(name.substring(first + 1));
	} else {
	return Integer.parseInt(name.substring(first + 1, last));
	}
	} catch (NumberFormatException e) { }
	}
	throw new IllegalArgumentException("file name does not match pattern");
	}

	/**
	* Return the name of the temporary directory being searched for
	* HotSpot PerfData backing store files.
	* <p>
	* This method generally returns the value of the java.io.tmpdir
	* property. However, on some platforms it may return a different
	* directory, as the JVM implementation may store the PerfData backing
	* store files in a different directory for performance reasons.
	*
	* @return String - the name of the temporary directory.
	*/
	public static String getTempDirectory() {
	return tmpDirName;
	}

	/**
	* Return the name of the temporary directory to be searched
	* for HotSpot PerfData backing store files for a given user.
	* <p>
	* This method generally returns the name of a subdirectory of
	* the directory indicated in the java.io.tmpdir property. However,
	* on some platforms it may return a different directory, as the
	* JVM implementation may store the PerfData backing store files
	* in a different directory for performance reasons.
	*
	* @return String - the name of the temporary directory.
	*/
	public static String getTempDirectory(String user) {
	return tmpDirName + dirNamePrefix + user + File.separator;
	}

	static {
	/*
	* For this to work, the target VM and this code need to use
	* the same directory. Instead of guessing which directory the
	* VM is using, we will ask.
	*/
	String tmpdir = sun.misc.VMSupport.getVMTemporaryDirectory();

	/*
	* Assure that the string returned has a trailing File.separator
	* character. This check was added because the Linux implementation
	* changed such that the java.io.tmpdir string no longer terminates
	* with a File.separator character.
	*/
	if (tmpdir.lastIndexOf(File.separator) != (tmpdir.length()-1)) {
	tmpdir = tmpdir + File.separator;
	}
	tmpDirName = tmpdir;
	}
	}

Back to index...