| java.net.URLClassLoader
 javax.management.loading.MLet
| MLet | | public class MLet extends URLClassLoader implements MLetMBean,MBeanRegistration(Code) | | This MLet service allows to instantiate and register one or several MBeans
in the MBean server coming from a remote URL. M-let is a shortcut for
management applet. The m-let service does this by loading an m-let text file,
which specifies information on the MBeans to be obtained. The information
on each MBean is specified in a single instance of a tag, called the MLET tag.
The location of the m-let text file is specified by a URL.
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-
This attribute specifies the full Java class name, including package name,
of the MBean to be obtained. The compiled
.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-
This attribute specifies the
.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"-
This mandatory attribute specifies one or more
.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:
- Each file must be separated from the one that follows it by a comma (,).
- archivelist must be enclosed in double quote marks.
All .jar files in archivelist must be stored in
the directory specified by the code base URL.
CODEBASE = codebaseURL-
This optional attribute specifies the code base URL of the MBean to be
obtained. It identifies the directory that contains the
.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 = mbeanname-
This optional attribute specifies the object name to be assigned to the
MBean instance when the m-let service registers it. If mbeanname
starts with the colon character (:), the domain part of the object name is
the domain of the agent. The m-let service invokes the
getDomain() method of the Framework class to
obtain this information.
VERSION = version-
This optional attribute specifies the version number of the MBean and
associated
.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.
- arglist
-
This optional attribute specifies a list of one or more parameters for the
MBean to be instantiated. This list describes the parameters to be passed
the MBean's constructor. Use the following syntax to specify each item in
arglist:
- <
ARG TYPE=argumentType VALUE=value>
- where:
- argumentType is the type of the argument that will be passed
as parameter to the MBean's constructor.
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).
When an m-let text file is loaded, an instance of each MBean specified
in the file is created and registered.
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
javax.management.loading.DefaultLoaderRepository DefaultLoaderRepository to load classes that could not be found in the loaded jar files.
|
| Constructor Summary | |
| public | MLet()
Constructs a new MLet using the default delegation parent ClassLoader. | | public | MLet(URL[] urls)
Constructs a new MLet for the specified URLs using the default delegation
parent ClassLoader. | | public | MLet(URL[] urls, ClassLoader parent)
Constructs a new MLet for the given URLs. | | public | MLet(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)
Constructs a new MLet for the specified URLs, parent class loader, and
URLStreamHandlerFactory. |
| Method Summary | |
| public void | addURL(String url)
Appends the specified URL to the list of URLs to search for classes and
resources. | | public void | addURL(URL url)
Appends the specified URL to the list of URLs to search for classes and
resources. | | protected synchronized java.lang.Class | findClass(java.lang.String name)
This is the main method for class loaders that is being redefined.
Parameters:
name - The name of the class. | | synchronized Class | findClassInMLet(String name)
| | protected String | findLibrary(String libname)
Returns the absolute path name of a native library. | | public String | getLibraryDirectory()
Gets the current directory used by the library loader for storing
native libraries before they are loaded into memory. | | public Set | getMBeansFromURL(String url)
Loads a text file containing MLET tags that define the MBeans to be
added to the agent. | | public Set | getMBeansFromURL(URL url)
Loads a text file containing MLET tags that define the MBeans to be
added to the agent. | | public URL[] | getURLs()
Returns the search path of URLs for loading classes and resources. | | public void | postDeregister()
Allows the m-let to perform any operations needed after having been
de-registered in the MBeanServer. | | public void | postRegister(Boolean registrationDone)
Allows the m-let to perform any operations needed after having been
registered in the MBeanServer or after the registration has failed.
Parameters:
registrationDone - - Indicates whether or not the m-let has beensuccessfully registered in the MBeanServer. | | public void | preDeregister()
Allows the m-let to perform any operations it needs before being
de-registered by the MBeanServer. | | public ObjectName | preRegister(MBeanServer server, ObjectName name)
This method allows the m-let to perform any operations it needs before
being registered in the MBeanServer. | | public void | readExternal(java.io.ObjectInput in)
This method reads the objects contents during Object Serialization. | | public void | setLibraryDirectory(String libDir)
Sets the directory used by the library loader for storing
native libraries before they are loaded into memory. | | void | setUseDefaultLoader(boolean flag)
| | public void | writeExternal(java.io.ObjectOutput out)
This method saves the objects contents during Object Serialization. |
| useDefaultLoader | | boolean useDefaultLoader(Code) | | |
| MLet | | public MLet()(Code) | | Constructs a new MLet using the default delegation parent ClassLoader.
|
| MLet | | public MLet(URL[] urls)(Code) | | 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.
Parameters:
urls - the URLs from which to load classes and resources |
| MLet | | public MLet(URL[] urls, ClassLoader parent)(Code) | | 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. 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.
Parameters:
urls - the URLs from which to load classes and resources
Parameters:
parent - the parent class loader for delegation |
| MLet | | public MLet(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)(Code) | | 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.
Parameters:
urls - - the URLs from which to load classes and resources
Parameters:
parent - - the parent class loader for delegation
Parameters:
factory - - the URLStreamHandlerFactory to use when creating URLs |
| addURL | | public void addURL(URL url)(Code) | | Appends the specified URL to the list of URLs to search for classes and
resources.
Parameters:
url - The url from which to load the MBeans in a string format. |
| findLibrary | | protected String findLibrary(String libname)(Code) | | 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:
- libstat.so
- SunOS/sparc/5.7/lib/libstat.so
the library stat on Windows NT 4.0 will be searched in the JAR file as:
- stat.dll
- WindowsNT/x86/4.0/lib/stat.dll
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.
Parameters:
libname - the library name. The absolute path of the native library. |
| getLibraryDirectory | | public String getLibraryDirectory()(Code) | | Gets the current directory used by the library loader for storing
native libraries before they are loaded into memory.
The current directory used by the library loader. |
| getMBeansFromURL | | public Set getMBeansFromURL(String url) throws ServiceNotFoundException(Code) | | 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 MBeanServer.
Parameters:
url - - The URL of the text file to be loaded as String object. A set containing one entry per MLET tag in the m-let text fileloaded. Each entry specifies either the ObjectInstance forthe created MBean, or a throwable object (that is, an erroror an exception) if the MBean could not be created.
exception:
javax.management.ServiceNotFoundException - - One of thefollowing 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.
See Also: MLetMBean.getMBeansFromURL(String) |
| getMBeansFromURL | | public Set getMBeansFromURL(URL url) throws ServiceNotFoundException(Code) | | 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 MBeanServer.
Parameters:
url - - The URL of the text file to be loaded as URL object. A set containing one entry per MLET tag in the m-let text fileloaded. Each entry specifies either the ObjectInstance forthe created MBean, or a throwable object (that is, anerror or an exception) if the MBean could not be created.
exception:
javax.management.ServiceNotFoundException - - One of thefollowing 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.
See Also: MLetMBean.getMBeansFromURL(URL) |
| getURLs | | public URL[] getURLs()(Code) | | 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.
This returns the search path of URLs for loading classesand resources
See Also: MLetMBean.getURLs |
| postDeregister | | public void postDeregister()(Code) | | Allows the m-let to perform any operations needed after having been
de-registered in the MBeanServer.
See Also: MBeanRegistration.postDeregister |
| postRegister | | public void postRegister(Boolean registrationDone)(Code) | | Allows the m-let to perform any operations needed after having been
registered in the MBeanServer or after the registration has failed.
Parameters:
registrationDone - - Indicates whether or not the m-let has beensuccessfully registered in the MBeanServer. The valuefalse means that either the registration phase has failed.
See Also: MBeanRegistration.postRegister(Boolean) |
| preDeregister | | public void preDeregister() throws Exception(Code) | | Allows the m-let to perform any operations it needs before being
de-registered by the MBeanServer.
exception:
java.langException - - This exception should be caught by theMBeanServer and re-thrown as an MBeanRegistrationException.
See Also: MBeanRegistration.preDeregister |
| preRegister | | public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception(Code) | | This method allows the m-let to perform any operations it needs before
being registered in the MBeanServer. If the ObjectName is null,
the m-let provides a default name for its registration :service=MLet
Parameters:
server - - The MBeanServer in which the m-let will be registered.
Parameters:
name - - The object name of the m-let. The name of the m-let registered.
exception:
java.lang.Exception - - This exception should be caught by theMBeanServer and re-thrown as an MBeanRegistrationException.
See Also: MBeanRegistration.preRegister(MBeanServerObjectName) |
| setLibraryDirectory | | public void setLibraryDirectory(String libDir)(Code) | | Sets the directory used by the library loader for storing
native libraries before they are loaded into memory.
Parameters:
libDir - The directory used by the library loader. |
| setUseDefaultLoader | | void setUseDefaultLoader(boolean flag)(Code) | | |
|
|