public class MLet extends URLClassLoader implements MLetMBean, MBeanRegistration, Externalizable
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 = mbeannameMBeanServer.getDefaultDomain().
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 MBeanServerFactory.getClassLoaderRepository(javax.management.MBeanServer)
to load classes that could not be found in the loaded jar files.
| Constructor and Description |
|---|
MLet()
Constructs a new MLet using the default delegation parent ClassLoader.
|
MLet(URL[] urls)
Constructs a new MLet for the specified URLs using the default
delegation parent ClassLoader.
|
MLet(URL[] urls,
boolean delegateToCLR)
Constructs a new MLet for the specified URLs using the default
delegation parent ClassLoader.
|
MLet(URL[] urls,
ClassLoader parent)
Constructs a new MLet for the given URLs.
|
MLet(URL[] urls,
ClassLoader parent,
boolean delegateToCLR)
Constructs a new MLet for the given URLs.
|
MLet(URL[] urls,
ClassLoader parent,
URLStreamHandlerFactory factory)
Constructs a new MLet for the specified URLs, parent class
loader, and URLStreamHandlerFactory.
|
MLet(URL[] urls,
ClassLoader parent,
URLStreamHandlerFactory factory,
boolean delegateToCLR)
Constructs a new MLet for the specified URLs, parent class
loader, and URLStreamHandlerFactory.
|
| Modifier and Type | Method and Description |
|---|---|
void |
addURL(String url)
Appends the specified URL to the list of URLs to search for classes and
resources.
|
void |
addURL(URL url)
Appends the specified URL to the list of URLs to search for classes and
resources.
|
protected URL |
check(String version,
URL codebase,
String jarfile,
MLetContent mlet)
This method is to be overridden when extending this service to
support caching and versioning.
|
protected Class<?> |
findClass(String name)
This is the main method for class loaders that is being redefined.
|
protected String |
findLibrary(String libname)
Returns the absolute path name of a native library.
|
String |
getLibraryDirectory()
Gets the current directory used by the library loader for
storing native libraries before they are loaded into memory.
|
Set<Object> |
getMBeansFromURL(String url)
Loads a text file containing MLET tags that define the MBeans to
be added to the MBean server.
|
Set<Object> |
getMBeansFromURL(URL url)
Loads a text file containing MLET tags that define the MBeans to
be added to the MBean server.
|
URL[] |
getURLs()
Returns the search path of URLs for loading classes and resources.
|
Class<?> |
loadClass(String name,
ClassLoaderRepository clr)
Load a class, using the given
ClassLoaderRepository if
the class is not found in this MLet's URLs. |
void |
postDeregister()
Allows the m-let to perform any operations needed after having been
unregistered in the MBean server.
|
void |
postRegister(Boolean registrationDone)
Allows the m-let to perform any operations needed after having been
registered in the MBean server or after the registration has failed.
|
void |
preDeregister()
Allows the m-let to perform any operations it needs before being unregistered
by the MBean server.
|
ObjectName |
preRegister(MBeanServer server,
ObjectName name)
Allows the m-let to perform any operations it needs before
being registered in the MBean server.
|
void |
readExternal(ObjectInput in)
Restore this MLet's contents from the given
ObjectInput. |
void |
setLibraryDirectory(String libdir)
Sets the directory used by the library loader for storing
native libraries before they are loaded into memory.
|
void |
writeExternal(ObjectOutput out)
Save this MLet's contents to the given
ObjectOutput. |
close, definePackage, findResource, findResources, getPermissions, getResourceAsStream, newInstance, newInstancedefineClass, defineClassclearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLoadedClass, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResource, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSignersclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitgetResource, getResourceAsStream, getResourcespublic MLet()
public MLet(URL[] urls)
urls - The URLs from which to load classes and resources.public MLet(URL[] urls, ClassLoader parent)
urls - The URLs from which to load classes and resources.parent - The parent class loader for delegation.public MLet(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)
urls - The URLs from which to load classes and resources.parent - The parent class loader for delegation.factory - The URLStreamHandlerFactory to use when creating URLs.public MLet(URL[] urls, boolean delegateToCLR)
urls - The URLs from which to load classes and resources.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 ClassLoaderRepository.public MLet(URL[] urls, ClassLoader parent, boolean delegateToCLR)
urls - The URLs from which to load classes and resources.parent - The parent class loader for delegation.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 ClassLoaderRepository.public MLet(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory, boolean delegateToCLR)
urls - The URLs from which to load classes and resources.parent - The parent class loader for delegation.factory - The URLStreamHandlerFactory to use when creating URLs.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 ClassLoaderRepository.public void addURL(URL url)
addURL in interface MLetMBeanaddURL in class URLClassLoaderurl - the URL to be added to the search path of URLspublic void addURL(String url) throws ServiceNotFoundException
addURL in interface MLetMBeanurl - the URL to add.ServiceNotFoundException - The specified URL is malformed.public URL[] getURLs()
getURLs in interface MLetMBeangetURLs in class URLClassLoaderpublic Set<Object> getMBeansFromURL(URL url) throws ServiceNotFoundException
getMBeansFromURL in interface MLetMBeanurl - The URL of the text file to be loaded as URL object.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.IllegalStateException - MLet MBean is not registered with an MBeanServer.public Set<Object> getMBeansFromURL(String url) throws ServiceNotFoundException
getMBeansFromURL in interface MLetMBeanurl - The URL of the text file to be loaded as String object.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.IllegalStateException - MLet MBean is not registered
with an MBeanServer.public String getLibraryDirectory()
getLibraryDirectory in interface MLetMBeanUnsupportedOperationException - if this implementation
does not support storing native libraries in this way.setLibraryDirectory(java.lang.String)public void setLibraryDirectory(String libdir)
setLibraryDirectory in interface MLetMBeanlibdir - The directory used by the library loader.UnsupportedOperationException - if this implementation
does not support storing native libraries in this way.getLibraryDirectory()public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception
preRegister in interface MBeanRegistrationserver - The MBean server in which the m-let will be registered.name - The object name of the m-let.Exception - This exception should be caught by the MBean server and re-thrown
as an MBeanRegistrationException.public void postRegister(Boolean registrationDone)
postRegister in interface MBeanRegistrationregistrationDone - Indicates whether or not the m-let has
been successfully registered in the MBean server. The value
false means that either the registration phase has failed.public void preDeregister()
throws Exception
preDeregister in interface MBeanRegistrationException - This exception should be caught
by the MBean server and re-thrown as an
MBeanRegistrationException.public void postDeregister()
postDeregister in interface MBeanRegistrationpublic void writeExternal(ObjectOutput out) throws IOException, UnsupportedOperationException
Save this MLet's contents to the given ObjectOutput.
Not all implementations support this method. Those that do not
throw UnsupportedOperationException. A subclass may
override this method to support it or to change the format of
the written data.
The format of the written data is not specified, but if
an implementation supports writeExternal(java.io.ObjectOutput) it must
also support readExternal(java.io.ObjectInput) in such a way that what is
written by the former can be read by the latter.
writeExternal in interface Externalizableout - The object output stream to write to.IOException - If a problem occurred while writing.UnsupportedOperationException - If this
implementation does not support this operation.public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException, UnsupportedOperationException
Restore this MLet's contents from the given ObjectInput.
Not all implementations support this method. Those that do not
throw 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 readExternal(java.io.ObjectInput) it must also
support writeExternal(java.io.ObjectOutput) in such a way that what is
written by the latter can be read by the former.
readExternal in interface Externalizablein - The object input stream to read from.IOException - if a problem occurred while reading.ClassNotFoundException - if the class for the object
being restored cannot be found.UnsupportedOperationException - if this
implementation does not support this operation.public Class<?> loadClass(String name, ClassLoaderRepository clr) throws ClassNotFoundException
Load a class, using the given ClassLoaderRepository if
the class is not found in this MLet's URLs. The given
ClassLoaderRepository can be null, in which case a ClassNotFoundException occurs immediately if the class is not
found in this MLet's URLs.
name - The name of the class we want to load.clr - The ClassLoaderRepository that will be used to search
for the given class, if it is not found in this
ClassLoader. May be null.ClassNotFoundException - The specified class could not be
found in this ClassLoader nor in the given
ClassLoaderRepository.protected Class<?> findClass(String name) throws ClassNotFoundException
findClass in class URLClassLoadername - The name of the class.ClassNotFoundException - The specified class could not be
found.protected String findLibrary(String libname)
OSName/OSArch/OSVersion/lib/nativelibname), i.e.
the library stat on Solaris SPARC 5.7 will be searched in the JAR file as:
More specifically, let nativelibname be the result of
System.mapLibraryName(libname). Then the following names are
searched in the JAR files, in order:
nativelibname
<os.name>/<os.arch>/<os.version>/lib/nativelibname
where <X> means System.getProperty(X) with any
spaces in the result removed, and / stands for the
file separator character (File.separator).
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.
findLibrary in class ClassLoaderlibname - The library name.System.loadLibrary(String),
System.mapLibraryName(String)protected URL check(String version, URL codebase, String jarfile, MLetContent mlet) throws Exception
This method is to be overridden when extending this service to
support caching and versioning. It is called from 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.
version - The version number of the .jar
file stored locally.codebase - The base URL of the remote .jar file.jarfile - The name of the .jar file to be loaded.mlet - The MLetContent instance that
represents the MLET tag.Exception - if the MBean is not to be loaded for some
reason. The exception will be added to the set returned by
getMBeansFromURL. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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