* The MLET tag has the following syntax:
*
* <MLET
* CODE = class | OBJECT = serfile
* ARCHIVE = "archiveList"
* [CODEBASE = codebaseURL]
* [NAME = mbeanname]
* [VERSION = version]
* >
* [arglist]
* </MLET>
*
* where: *
CODE = class.class file of the MBean must be contained in one of the .jar files specified by the ARCHIVE
* attribute. Either CODE or OBJECT must be present.
* OBJECT = serfile.ser file that contains a serialized representation of the MBean to be obtained.
* This file must be contained in one of the .jar files specified by the ARCHIVE attribute. If the .jar file contains a directory hierarchy, specify the path of the file within this hierarchy. Otherwise a match will not be found. Either CODE or OBJECT must be present.
* ARCHIVE = "archiveList".jar files
* containing MBeans or other resources used by
* the MBean to be obtained. One of the .jar files must contain the file specified by the CODE or OBJECT attribute.
* If archivelist contains more than one file:
* .jar files in archivelist must be stored in the directory specified by the code base URL.
* CODEBASE = codebaseURL.jar files specified by the ARCHIVE attribute. Specify this attribute only if the .jar files are not in the same
* directory as the m-let text file. If this attribute is not specified, the base URL of the m-let text file is used.
* NAME = mbeannamegetDomain() method of the Framework class to
* obtain this information.
* VERSION = version.jar files to be obtained. This version number can
* be used to specify that the .jar files are loaded from the
* server to update those stored locally in the cache the next time the m-let
* text file is loaded. version must be a series of non-negative
* decimal integers each separated by a period from the one that precedes it.
* *
ARG TYPE=argumentType VALUE=value>*
The arguments' type in the argument list should be a Java primitive type or a Java basic type
* (java.lang.Boolean, java.lang.Byte, java.lang.Short, java.lang.Long, java.lang.Integer, java.lang.Float, java.lang.Double, java.lang.String).
*
* The m-let Service extends the java.net.URLClassLoader and can be used to load remote classes
* and jar files in the VM of the agent.
*
Note - The MLet class loader uses the {@link javax.management.MBeanServerFactory#getClassLoaderRepository(javax.management.MBeanServer)}
* to load classes that could not be found in the loaded jar files.
*
* @since 1.5
*/
public class MLet extends java.net.URLClassLoader
implements MLetMBean, MBeanRegistration, Externalizable {
private static final long serialVersionUID = 3636148327800330130L;
/*
* ------------------------------------------
* PRIVATE VARIABLES
* ------------------------------------------
*/
/**
* The reference to the MBean server.
* @serial
*/
private MBeanServer server = null;
/**
* The list of instances of the MLetContant
* class found at the specified URL.
* @serial
*/
private Vector mletList = new Vector();
/**
* The directory used for storing libraries locally before they are loaded.
*/
private String libraryDirectory;
/**
* The object name of the MLet Service.
* @serial
*/
private ObjectName mletObjectName = null;
/**
* The URLs of the MLet Service.
* @serial
*/
private URL[] myUrls = null;
/**
* The name of this class to be used for trace messages
*/
private static final String dbgTag = "MLet";
/**
* What ClassLoaderRepository, if any, to use if this MLet
* doesn't find an asked-for class.
*/
private transient ClassLoaderRepository currentClr;
/**
* True if we should consult the {@link ClassLoaderRepository}
* when we do not find a class ourselves.
*/
private transient boolean delegateToCLR;
/**
* objects maps from primitive classes to primitive object classes.
*/
private Hashtable primitiveClasses = new Hashtable(8) ;
{
primitiveClasses.put(Boolean.TYPE.toString(), Boolean.class);
primitiveClasses.put(Character.TYPE.toString(), Character.class);
primitiveClasses.put(Byte.TYPE.toString(), Byte.class);
primitiveClasses.put(Short.TYPE.toString(), Short.class);
primitiveClasses.put(Integer.TYPE.toString(), Integer.class);
primitiveClasses.put(Long.TYPE.toString(), Long.class);
primitiveClasses.put(Float.TYPE.toString(), Float.class);
primitiveClasses.put(Double.TYPE.toString(), Double.class);
}
/*
* ------------------------------------------
* CONSTRUCTORS
* ------------------------------------------
*/
/*
* The constructor stuff would be considerably simplified if our
* parent, URLClassLoader, specified that its one- and
* two-argument constructors were equivalent to its
* three-argument constructor with trailing null arguments. But
* it doesn't, which prevents us from having all the constructors
* but one call this(...args...).
*/
/**
* Constructs a new MLet using the default delegation parent ClassLoader.
*/
public MLet() {
this(new URL[0]);
}
/**
* Constructs a new MLet for the specified URLs using the default
* delegation parent ClassLoader. The URLs will be searched in
* the order specified for classes and resources after first
* searching in the parent class loader.
*
* @param urls The URLs from which to load classes and resources.
*
*/
public MLet(URL[] urls) {
this(urls, true);
}
/**
* Constructs a new MLet for the given URLs. The URLs will be
* searched in the order specified for classes and resources
* after first searching in the specified parent class loader.
* The parent argument will be used as the parent class loader
* for delegation.
*
* @param urls The URLs from which to load classes and resources.
* @param parent The parent class loader for delegation.
*
*/
public MLet(URL[] urls, ClassLoader parent) {
this(urls, parent, true);
}
/**
* Constructs a new MLet for the specified URLs, parent class
* loader, and URLStreamHandlerFactory. The parent argument will
* be used as the parent class loader for delegation. The factory
* argument will be used as the stream handler factory to obtain
* protocol handlers when creating new URLs.
*
* @param urls The URLs from which to load classes and resources.
* @param parent The parent class loader for delegation.
* @param factory The URLStreamHandlerFactory to use when creating URLs.
*
*/
public MLet(URL[] urls,
ClassLoader parent,
URLStreamHandlerFactory factory) {
this(urls, parent, factory, true);
}
/**
* Constructs a new MLet for the specified URLs using the default
* delegation parent ClassLoader. The URLs will be searched in
* the order specified for classes and resources after first
* searching in the parent class loader.
*
* @param urls The URLs from which to load classes and resources.
* @param delegateToCLR True if, when a class is not found in
* either the parent ClassLoader or the URLs, the MLet should delegate
* to its containing MBeanServer's {@link ClassLoaderRepository}.
*
* @since.unbundled JMX 1.2
*/
public MLet(URL[] urls, boolean delegateToCLR) {
super(urls);
init(delegateToCLR);
}
/**
* Constructs a new MLet for the given URLs. The URLs will be
* searched in the order specified for classes and resources
* after first searching in the specified parent class loader.
* The parent argument will be used as the parent class loader
* for delegation.
*
* @param urls The URLs from which to load classes and resources.
* @param parent The parent class loader for delegation.
* @param delegateToCLR True if, when a class is not found in
* either the parent ClassLoader or the URLs, the MLet should delegate
* to its containing MBeanServer's {@link ClassLoaderRepository}.
*
* @since.unbundled JMX 1.2
*/
public MLet(URL[] urls, ClassLoader parent, boolean delegateToCLR) {
super(urls, parent);
init(delegateToCLR);
}
/**
* Constructs a new MLet for the specified URLs, parent class
* loader, and URLStreamHandlerFactory. The parent argument will
* be used as the parent class loader for delegation. The factory
* argument will be used as the stream handler factory to obtain
* protocol handlers when creating new URLs.
*
* @param urls The URLs from which to load classes and resources.
* @param parent The parent class loader for delegation.
* @param factory The URLStreamHandlerFactory to use when creating URLs.
* @param delegateToCLR True if, when a class is not found in
* either the parent ClassLoader or the URLs, the MLet should delegate
* to its containing MBeanServer's {@link ClassLoaderRepository}.
*
* @since.unbundled JMX 1.2
*/
public MLet(URL[] urls,
ClassLoader parent,
URLStreamHandlerFactory factory,
boolean delegateToCLR) {
super(urls, parent, factory);
init(delegateToCLR);
}
private void init(boolean delegateToCLR) {
this.delegateToCLR = delegateToCLR;
try {
libraryDirectory = System.getProperty(JmxProperties.MLET_LIB_DIR);
if (libraryDirectory == null)
libraryDirectory = getTmpDir();
} catch (SecurityException e) {
// OK : We don't do AccessController.doPrivileged, but we don't
// stop the user from creating an MLet just because they
// can't read the MLET_LIB_DIR or java.io.tmpdir properties
// either.
}
}
/*
* ------------------------------------------
* PUBLIC METHODS
* ------------------------------------------
*/
/**
* Appends the specified URL to the list of URLs to search for classes and
* resources.
*/
public void addURL(URL url) {
if (!Arrays.asList(getURLs()).contains(url))
super.addURL(url);
}
/**
* Appends the specified URL to the list of URLs to search for classes and
* resources.
* @exception ServiceNotFoundException The specified URL is malformed.
*/
public void addURL(String url) throws ServiceNotFoundException {
try {
URL ur = new URL(url);
if (!Arrays.asList(getURLs()).contains(ur))
super.addURL(ur);
} catch (MalformedURLException e) {
debug("addURL", url + ": Malformed URL. " + e);
throw new
ServiceNotFoundException("The specified URL is malformed");
}
}
/** Returns the search path of URLs for loading classes and resources.
* This includes the original list of URLs specified to the constructor,
* along with any URLs subsequently appended by the addURL() method.
*/
public URL[] getURLs() {
return super.getURLs();
}
/**
* Loads a text file containing MLET tags that define the MBeans to
* be added to the agent. The location of the text file is specified by
* a URL. The MBeans specified in the MLET file will be instantiated and
* registered by the MBean server.
*
* @param url The URL of the text file to be loaded as URL object.
*
* @return A set containing one entry per MLET tag in the m-let text file loaded.
* Each entry specifies either the ObjectInstance for the created MBean, or a throwable object
* (that is, an error or an exception) if the MBean could not be created.
*
* @exception ServiceNotFoundException One of the following errors has occurred: The m-let text file does
* not contain an MLET tag, the m-let text file is not found, a mandatory
* attribute of the MLET tag is not specified, the value of url is
* null.
* @exception IllegalStateException MLet MBean is not registered with an MBeanServer.
*/
public Set getMBeansFromURL(URL url) throws ServiceNotFoundException {
if (url == null) {
throw new ServiceNotFoundException("The specified URL is null");
}
return getMBeansFromURL(url.toString());
}
/**
* Loads a text file containing MLET tags that define the MBeans to
* be added to the agent. The location of the text file is specified by
* a URL. The MBeans specified in the MLET file will be instantiated and
* registered by the MBean server.
*
* @param url The URL of the text file to be loaded as String object.
*
* @return A set containing one entry per MLET tag in the m-let text file loaded.
* Each entry specifies either the ObjectInstance for the created MBean, or a throwable object
* (that is, an error or an exception) if the MBean could not be created.
*
* @exception ServiceNotFoundException One of the following errors has occurred: The m-let text file does
* not contain an MLET tag, the m-let text file is not found, a mandatory
* attribute of the MLET tag is not specified, the url is malformed.
* @exception IllegalStateException MLet MBean is not registered with an MBeanServer.
*
*/
public Set getMBeansFromURL(String url) throws ServiceNotFoundException {
String mth = "getMBeansFromURL";
if (server == null) {
throw new IllegalStateException("This MLet MBean is not registered with an MBeanServer.");
}
// Parse arguments
if (url == null) {
if (isTraceOn()) {
trace(mth, "URL is null");
}
throw new ServiceNotFoundException("The specified URL is null");
} else {
url = url.replace(File.separatorChar,'/');
}
if (isTraceOn()) {
trace(mth, "
The format of the written data is not specified, but if * an implementation supports {@link #writeExternal} it must * also support {@link #readExternal} in such a way that what is * written by the former can be read by the latter.
* * @param out The object output stream to write to. * * @exception IOException If a problem occurred while writing. * @exception UnsupportedOperationException If this * implementation does not support this operation. */ public void writeExternal(ObjectOutput out) throws IOException, UnsupportedOperationException { throw new UnsupportedOperationException("MLet.writeExternal"); } /** *Restore this MLet's contents from the given {@link ObjectInput}. * Not all implementations support this method. Those that do not * throw {@link UnsupportedOperationException}. A subclass may * override this method to support it or to change the format of * the read data.
* *The format of the read data is not specified, but if an * implementation supports {@link #readExternal} it must also * support {@link #writeExternal} in such a way that what is * written by the latter can be read by the former.
* * @param in The object input stream to read from. * * @exception IOException if a problem occurred while reading. * @exception ClassNotFoundException if the class for the object * being restored cannot be found. * @exception UnsupportedOperationException if this * implementation does not support this operation. */ public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException, UnsupportedOperationException { throw new UnsupportedOperationException("MLet.readExternal"); } /* * ------------------------------------------ * PACKAGE METHODS * ------------------------------------------ */ /** *Load a class, using the given {@link ClassLoaderRepository} if * the class is not found in this MLet's URLs. The given * ClassLoaderRepository can be null, in which case a {@link * ClassNotFoundException} occurs immediately if the class is not * found in this MLet's URLs.
* * @param name The name of the class we want to load. * @param clr The ClassLoaderRepository that will be used to search * for the given class, if it is not found in this * ClassLoader. May be null. * @return The resulting Class object. * @exception ClassNotFoundException The specified class could not be * found in this ClassLoader nor in the given * ClassLoaderRepository. * * @since.unbundled JMX 1.1 */ public synchronized Class loadClass(String name, ClassLoaderRepository clr) throws ClassNotFoundException { final ClassLoaderRepository before=currentClr; try { currentClr = clr; final Class c = loadClass(name); return c; } finally { currentClr = before; } } /* * ------------------------------------------ * PROTECTED METHODS * ------------------------------------------ */ /** * This is the main method for class loaders that is being redefined. * * @param name The name of the class. * * @return The resulting Class object. * * @exception ClassNotFoundException The specified class could not be * found. */ protected Class findClass(String name) throws ClassNotFoundException { /* currentClr is context sensitive - used to avoid recursion in the class loader repository. (This is no longer necessary with the new CLR semantics but is kept for compatibility with code that might have called the two-parameter loadClass explicitly.) */ return findClass(name, currentClr); } /** * Called by {@link MLet#findClass(java.lang.String)}. * * @param name The name of the class that we want to load/find. * @param clr The ClassLoaderRepository that can be used to search * for the given class. This parameter is *null when called from within the
* {@link javax.management.MBeanServerFactory#getClassLoaderRepository(javax.management.MBeanServer) Class Loader Repository}.
* @exception ClassNotFoundException The specified class could not be
* found.
*
**/
Class findClass(String name, ClassLoaderRepository clr)
throws ClassNotFoundException {
Class c = null;
if (isTraceOn()) {
trace("findClass", name);
}
// Try looking in the JAR:
try {
c = super.findClass(name);
if (isTraceOn()) {
trace("findClass", "Class "+name+
" loaded through mlet classloader");
}
} catch (ClassNotFoundException e) {
// Drop through
debug("findClass", "Class "+name+ " not found locally.");
}
// if we are not called from the ClassLoaderRepository
if (c == null && delegateToCLR && clr != null) {
// Try the classloader repository:
//
try {
debug("findClass", "Class "+name+": looking in CLR");
c = clr.loadClassBefore(this, name);
// The loadClassBefore method never returns null.
// If the class is not found we get an exception.
if (isTraceOn()) {
trace("findClass", "Class "+name+
" loaded through the default classloader repository");
}
} catch (ClassNotFoundException e) {
debug("findClass", "Class "+name+ " not found in CLR.");
// Drop through
}
}
if (c == null) {
debug("findClass","Failed to load class " + name);
throw new ClassNotFoundException(name);
}
return c;
}
/**
* Returns the absolute path name of a native library. The VM invokes this method to locate the native
* libraries that belong to classes loaded with this class loader. Libraries are searched in the JAR files
* using first just the native library name and if not found the native library name together with the
* architecture-specific path name (OSName/OSArch/OSVersion/lib/nativelibname), i.e.
* * the library stat on Solaris SPARC 5.7 will be searched in the JAR file as: *
* If this method returns null, i.e. the libraries were not found in any of the JAR
* files loaded with this class loader, the VM searches the library along the path specified as
* the java.library.path property.
*
* @param libname The library name.
*
* @return The absolute path of the native library.
*/
protected String findLibrary(String libname) {
String abs_path;
String mth = "findLibrary";
// Get the platform-specific string representing a native library.
//
String nativelibname = System.mapLibraryName(libname);
//
// See if the native library is accessible as a resource through the JAR file.
//
if (isTraceOn()) {
trace(mth, "Search " + libname + " in all JAR files.");
}
// First try to locate the library in the JAR file using only the native library name.
// e.g. if user requested a load for "foo" on Solaris SPARC 5.7 we try to load
// "libfoo.so" from the JAR file.
//
if (isTraceOn()) {
trace(mth, "loadLibraryAsResource(" + nativelibname + ")");
}
abs_path = loadLibraryAsResource(nativelibname);
if (abs_path != null) {
if (isTraceOn()) {
trace(mth, nativelibname + " loaded " + "absolute path = " + abs_path);
}
return abs_path;
}
// Next try to locate it using the native library name and the architecture-specific path name.
// e.g. if user requested a load for "foo" on Solaris SPARC 5.7 we try to load
// "SunOS/sparc/5.7/lib/libfoo.so" from the JAR file.
//
nativelibname = removeSpace(System.getProperty("os.name")) + File.separator +
removeSpace(System.getProperty("os.arch")) + File.separator +
removeSpace(System.getProperty("os.version")) + File.separator +
"lib" + File.separator + nativelibname;
if (isTraceOn()) {
trace(mth, "loadLibraryAsResource(" + nativelibname + ")");
}
abs_path = loadLibraryAsResource(nativelibname);
if (abs_path != null) {
if (isTraceOn()) {
trace(mth, nativelibname + " loaded " + "absolute path = " + abs_path);
}
return abs_path;
}
//
// All paths exhausted, library not found in JAR file.
//
if (isTraceOn()) {
trace(mth, libname + " not found in any JAR file.");
trace(mth, "Search " + libname + " along the path specified as the java.library.path property.");
}
// Let the VM search the library along the path
// specified as the java.library.path property.
//
return null;
}
/*
* ------------------------------------------
* PRIVATE METHODS
* ------------------------------------------
*/
private String getTmpDir() {
// JDK 1.4
String tmpDir = (String)System.getProperty("java.io.tmpdir");
if (tmpDir != null) return tmpDir;
// JDK < 1.4
File tmpFile = null;
try {
// Try to guess the system temporary dir...
tmpFile = File.createTempFile("tmp","jmx");
if (tmpFile == null) return null;
final File tmpDirFile = tmpFile.getParentFile();
if (tmpDirFile == null) return null;
return tmpDirFile.getAbsolutePath();
} catch (Exception x) {
debug("getTmpDir","Failed to determine system temporary dir.");
return null;
} finally {
// Cleanup ...
if (tmpFile!=null) try {
tmpFile.delete();
} catch (Exception x) {
debug("getTmpDir","Failed to delete temporary file: " + x.getMessage());
}
}
}
/**
* Search the specified native library in any of the JAR files loaded by this classloader.
* If the library is found copy it into the library directory and return the absolute path.
* If the library is not found then return null.
*/
private synchronized String loadLibraryAsResource(String libname) {
try {
InputStream is = getResourceAsStream(libname.replace(File.separatorChar,'/'));
if (is != null) {
File directory = new File(libraryDirectory);
directory.mkdirs();
File file = File.createTempFile(libname + ".", null, directory);
file.deleteOnExit();
FileOutputStream fileOutput = new FileOutputStream(file);
int c;
while ((c = is.read()) != -1) {
fileOutput.write(c);
}
is.close();
fileOutput.close();
if (file.exists()) {
return file.getAbsolutePath();
}
}
} catch (Exception e) {
debug("loadLibraryAsResource",libname+
": Failed to load library. " + e);
return null;
}
return null;
}
/**
* Removes any white space from a string. This is used to
* convert strings such as "Windows NT" to "WindowsNT".
*/
private String removeSpace(String s) {
s = s.trim();
int j = s.indexOf(' ');
if (j == -1) {
return s;
}
String temp = "";
int k = 0;
while (j != -1) {
s = s.substring(k);
j = s.indexOf(' ');
if (j != -1) {
temp = temp + s.substring(0, j);
} else {
temp = temp + s.substring(0);
}
k = j + 1;
}
return temp;
}
/**
*
This method is to be overridden when extending this service to * support caching and versioning. It is called from {@link * #getMBeansFromURL getMBeansFromURL} when the version, * codebase, and jarfile have been extracted from the MLet file, * and can be used to verify that it is all right to load the * given MBean, or to replace the given URL with a different one.
* *The default implementation of this method returns
* codebase unchanged.
.jar
* file stored locally.
* @param codebase The base URL of the remote .jar file.
* @param jarfile The name of the .jar file to be loaded.
* @param mlet The MLetContent instance that
* represents the MLET tag.
*
* @return the codebase to use for the loaded MBean. The returned
* value should not be null.
*
* @exception Exception if the MBean is not to be loaded for some
* reason. The exception will be added to the set returned by
* {@link #getMBeansFromURL getMBeansFromURL}.
*
* @since.unbundled JMX 1.2
*/
protected URL check(String version, URL codebase, String jarfile,
MLetContent mlet)
throws Exception {
return codebase;
}
/**
* Loads the serialized object specified by the OBJECT
* attribute of the MLET tag.
*
* @param codebase The codebase.
* @param filename The name of the file containing the serialized object.
* @return The serialized object.
* @exception ClassNotFoundException The specified serialized object could not be found.
* @exception IOException An I/O error occurred while loading serialized object.
*/
private Object loadSerializedObject(URL codebase, String filename) throws IOException, ClassNotFoundException {
if (filename != null) {
filename = filename.replace(File.separatorChar,'/');
}
if (isTraceOn()) {
trace("loadSerializedObject", codebase.toString() + filename);
}
InputStream is = getResourceAsStream(filename);
if (is != null) {
try {
ObjectInputStream ois = new MLetObjectInputStream(is, this);
Object serObject = ois.readObject();
ois.close();
return serObject;
} catch (IOException e) {
if (isDebugOn()) {
debug("loadSerializedObject", "Exception while deserializing " + filename + ", " + e.getMessage());
}
throw e;
} catch (ClassNotFoundException e) {
if (isDebugOn()) {
debug("loadSerializedObject", "Exception while deserializing " + filename + ", " + e.getMessage());
}
throw e;
}
} else {
if (isDebugOn()) {
debug("loadSerializedObject", "Error: File " + filename + " containing serialized object not found");
}
throw new Error("File " + filename + " containing serialized object not found");
}
}
/**
* Converts the String value of the constructor's parameter to
* a basic Java object with the type of the parameter.
*/
private Object constructParameter(String param, String type) {
// check if it is a primitive type
Class c = (Class) primitiveClasses.get(type);
if (c != null) {
try {
Constructor cons =
c.getConstructor(new Class[] {String.class});
Object[] oo = new Object[1];
oo[0]=param;
return(cons.newInstance(oo));
} catch (Exception e) {
if (isDebugOn()) {
debug(dbgTag, "constructParameter", "Unexpected Exception" + e.getClass().getName() + " occured");
}
}
}
if (type.compareTo("java.lang.Boolean") == 0)
return new Boolean(param);
if (type.compareTo("java.lang.Byte") == 0)
return new Byte(param);
if (type.compareTo("java.lang.Short") == 0)
return new Short(param);
if (type.compareTo("java.lang.Long") == 0)
return new Long(param);
if (type.compareTo("java.lang.Integer") == 0)
return new Integer(param);
if (type.compareTo("java.lang.Float") == 0)
return new Float(param);
if (type.compareTo("java.lang.Double") == 0)
return new Double(param);
if (type.compareTo("java.lang.String") == 0)
return param;
return param;
}
private synchronized void setMBeanServer(final MBeanServer server) {
this.server = server;
currentClr = (ClassLoaderRepository)
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
return server.getClassLoaderRepository();
}
});
}
// TRACES & DEBUG
//---------------
private boolean isTraceOn() {
return Trace.isSelected(Trace.LEVEL_TRACE, Trace.INFO_MLET);
}
private void trace(String clz, String func, String info) {
Trace.send(Trace.LEVEL_TRACE, Trace.INFO_MLET, clz, func, info);
}
private void trace(String func, String info) {
trace(dbgTag, func, info);
}
private boolean isDebugOn() {
return Trace.isSelected(Trace.LEVEL_DEBUG, Trace.INFO_MLET);
}
private void debug(String clz, String func, String info) {
Trace.send(Trace.LEVEL_DEBUG, Trace.INFO_MLET, clz, func, info);
}
private void debug(String func, String info) {
debug(dbgTag, func, info);
}
}