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SUMMARY: JavaDoc of mucode.MuServer JAVADOC | Sourc code of mucode.MuServer SOURCE | Download mucode.MuServer DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD

mucode
Class MuServer  view MuServer download MuServer.java

java.lang.Object
  extended byjava.lang.Thread
      extended bymucode.MuServer
All Implemented Interfaces:
MuConstants, java.lang.Runnable
public class MuServer
extends java.lang.Thread
implements MuConstants

Provides an abstraction of the run-time support needed to receive and/or execute mobile code. A MuServer object does not enable per se the handling of incoming mobile code, rather they provide only the capability to ship mobile code to other µServers. In order to accept incoming mobile code, a thread listening for incoming groups must be explicitly started in the µServer by calling the boot() 55 method. This choice minimizes the overhead introduced by the run-time support, wasting a thread only when really needed. Multiple servers can be started on the same Java VM or on different Java VMs on the same host, as long as their are given different port numbers. However, the name spaces defined by their (shared) class spaces are disjoint, and their sets of ubiquitous classes (see isUbiquitous(java.lang.String) 55 and MuClassLoader) may be different.

Version:
1.0

Nested Class Summary
 
Nested classes inherited from class java.lang.Thread
java.lang.Thread.UncaughtExceptionHandler
 
Field Summary
private static java.lang.String builtinUbiPackages
           
(package private) static java.lang.String[] classpath
          Contains all the directories listed in the CLASSPATH system variable.
private  boolean compressionON
           
private  boolean debugON
           
protected static MuClassLoader defaultLoader
          The class loader for all non-mobile threads.
protected static java.util.Properties defaultProperties
          The default properties.
(package private) static java.lang.String ERRMSG
           
private  boolean errorsON
           
protected  MuClassLoader incomingLoader
          The class loader used to handle incoming groups.
protected static java.util.Hashtable loaders
          The "persistency root" for class loaders.
private  boolean messagesON
           
private  int port
           
 java.util.Properties properties
          The properties of this µServer.
private  java.lang.Thread serverThread
          Needed to perform the shutdown of the server.
protected  ClassSpace sharedSpace
          The class space visible outside the server.
private  long timeout
           
private  java.util.Vector ubiquitousClasses
          Holds the list of ubiquitous classes that are not in ubiquitous packages.
private  java.util.Vector ubiquitousPackagePrefixes
          Holds the list of packages that are ubiquitous, and whose subpackages are considered ubiquitous as well.
private  java.util.Vector ubiquitousPackages
          Holds the list of ubiquitous packages.
 
Fields inherited from class java.lang.Thread
MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY
 
Fields inherited from interface mucode.MuConstants
COMPRESSIONkey, DEBUGkey, DYN_LINK, ERRORSkey, GROUP, MESSAGESkey, OK, PACKAGE_NAME, PORTkey, REMOTE_ERROR, SERVER_PORT, TIMEOUT, TIMEOUTkey, UBICLASSESkey, UBIPACKAGESkey, UNKNOWN
 
Constructor Summary
MuServer()
          The µServer constructor.
 
Method Summary
 void addUbiquitousClass(java.lang.String className)
          Add all the classes contained in a package to the set of ubiquitous classes, i.e., the classes present on every node.
 void addUbiquitousPackage(java.lang.String packageName)
          Specify the packages that are considered to be ubiquitous, i.e., whose classes are assumed to be present on every node.
 void boot()
          Start the run-time support listening for incoming groups.
protected  void cleanup()
           
protected  MuClassLoader createClassLoader()
           
 Group createGroup(java.lang.String root, java.lang.String handler)
          Create a new Group object.
(package private)  void D(java.lang.String msg)
           
(package private)  void D(java.lang.String msg, java.lang.Throwable e)
           
(package private)  void Err(java.lang.String msg)
           
(package private)  void Err(java.lang.String msg, java.lang.Throwable e)
           
 int getPort()
          Retrieve the socket port the µServer is listening to.
 ClassSpace getPrivateClassSpace()
          Retrieves the private class space associated with the thread object invoking the method.
static MuServer getServer()
          Retrieve the µServer managing the thread object invoking this method.
static MuServer getServer(java.lang.Object obj)
          Retrieve the µServer associated with the given object.
static MuServer getServer(java.lang.Thread t)
          Retrieve the µServer managing the thread object passed as a parameter.
 ClassSpace getSharedClassSpace()
          Retrieve the shared class space associated with the µServer containing the thread object invoking the method.
 long getTimeout()
          Retrieve the timeout (in milliseconds) for synchronous transfers.
private  void insertUbiquitousPackage(java.lang.String packageName)
           
 boolean isCompressionOn()
          Return true, if GZIP compression is used during outgoing communication, false otherwise.
 boolean isDebugOn()
          Return true, if debug messages are shown on the standard output stream, false otherwise.
 boolean isErrorsOn()
          Return true, if error messages are shown on the standard error stream, false otherwise.
 boolean isMessagesOn()
          Return true, if messages are shown on the standard output stream, false otherwise.
 boolean isUbiquitous(java.lang.String className)
          Return true if a class is ubiquitous, (i.e., it is assumed to be present on every node), false otherwise.
 void loadProperties(java.lang.String filename)
          Loads into the server the properties read from a file.
private  void loadPropertyVars()
           
(package private)  void M(java.lang.String msg)
          Output Message handling
(package private) static java.net.InetAddress parseHost(java.lang.String destination)
          Extracts the host component from an address specified as host:port.
(package private) static int parsePort(java.lang.String destination)
          Extracts the port component from an address specified as host:port.
 void run()
          Implements the Runnable interface, and contains the behavior of the server.
 void setProperty(java.lang.String key, java.lang.String value)
          Set the value of a property.
 void shutDown()
          Stop the run-time support listening for incoming groups.
 
Methods inherited from class java.lang.Thread
activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

ERRMSG

static final java.lang.String ERRMSG
See Also:
Constant Field Values

builtinUbiPackages

private static final java.lang.String builtinUbiPackages
See Also:
Constant Field Values

defaultProperties

protected static java.util.Properties defaultProperties
The default properties.

properties

public java.util.Properties properties
The properties of this µServer. Properties are stored as pairs . The set of legal keys (here, the constantsare shown, rather than the actual key string), their corresponding default value, and their meaning is:

Key Default value Description
MESSAGESkey true Activates server messages on the standard output stream.
ERRORSkey true Activates errors messages on the standard error stream.
DEBUGkey false Activates debugging messages on the standard output stream.
COMPRESSIONkey true Activates compression of the serialized stream containing outgoing mobile code.
PORTkey 1968 The port number for incoming connections.
TIMEOUTkey 30000 The timeout for network connections.

Properties can be set using the method setProperty 55 , and retrieved using the methods of java.util.Properties.

port

private int port

timeout

private long timeout

compressionON

private boolean compressionON

errorsON

private boolean errorsON

debugON

private boolean debugON

messagesON

private boolean messagesON

incomingLoader

protected MuClassLoader incomingLoader
The class loader used to handle incoming groups.

defaultLoader

protected static MuClassLoader defaultLoader
The class loader for all non-mobile threads. There's only one per VM and doesn't have any server associated with it.

sharedSpace

protected ClassSpace sharedSpace
The class space visible outside the server.

loaders

protected static java.util.Hashtable loaders
The "persistency root" for class loaders. Key: Thread object. Value: class loader.

serverThread

private java.lang.Thread serverThread
Needed to perform the shutdown of the server.

ubiquitousPackagePrefixes

private java.util.Vector ubiquitousPackagePrefixes
Holds the list of packages that are ubiquitous, and whose subpackages are considered ubiquitous as well.

ubiquitousPackages

private java.util.Vector ubiquitousPackages
Holds the list of ubiquitous packages.

ubiquitousClasses

private java.util.Vector ubiquitousClasses
Holds the list of ubiquitous classes that are not in ubiquitous packages.

classpath

static java.lang.String[] classpath
Contains all the directories listed in the CLASSPATH system variable. Used for locating a class in the system.

Constructor Detail

MuServer

public MuServer()
The µServer constructor.

Method Detail

setProperty

public void setProperty(java.lang.String key,
                        java.lang.String value)
Set the value of a property. See properties 55 for a list of key, default values, and their meaning.

loadProperties

public void loadProperties(java.lang.String filename)
                    throws java.io.FileNotFoundException,
                           java.io.IOException
Loads into the server the properties read from a file. The format is the same used by Java, i.e., key=value on separate lines. The following would be a property file for the default values: 
 messages=true
 errors=true
 debug=false
 compression=true
 port=1968
 timeout=30000
 ubiclasses=
 ubipackages=java.* javax.* mucode.*

loadPropertyVars

private void loadPropertyVars()

getPort

public int getPort()
Retrieve the socket port the µServer is listening to.

getTimeout

public long getTimeout()
Retrieve the timeout (in milliseconds) for synchronous transfers.

isCompressionOn

public boolean isCompressionOn()
Return true, if GZIP compression is used during outgoing communication, false otherwise.

isDebugOn

public boolean isDebugOn()
Return true, if debug messages are shown on the standard output stream, false otherwise.

isErrorsOn

public boolean isErrorsOn()
Return true, if error messages are shown on the standard error stream, false otherwise.

isMessagesOn

public boolean isMessagesOn()
Return true, if messages are shown on the standard output stream, false otherwise.

addUbiquitousPackage

public final void addUbiquitousPackage(java.lang.String packageName)
Specify the packages that are considered to be ubiquitous, i.e., whose classes are assumed to be present on every node. Ubiquitous classes are the first one to be searched by the class loader. If packageName ends with .*, all the subpackages are made ubiquitous as well. Thus, for instance, calling this method by passing ("mypackage") results in considering ubiquitous only all the classes in mypackage, but not for instance those in mypackage.mysubpackage. By default, system classes (java.* and subpackages), Java extensions (javax.* and subpackages), and µCode classes (mucode.* and subpackages) are ubiquitous.

insertUbiquitousPackage

private final void insertUbiquitousPackage(java.lang.String packageName)

addUbiquitousClass

public final void addUbiquitousClass(java.lang.String className)
Add all the classes contained in a package to the set of ubiquitous classes, i.e., the classes present on every node. Ubiquitous classes are the first one to be searched by the class loader. System classes (java.*, and the primitive types) and µCode classes (mucode.*) are ubiquitous by default.

isUbiquitous

public final boolean isUbiquitous(java.lang.String className)
Return true if a class is ubiquitous, (i.e., it is assumed to be present on every node), false otherwise.

createGroup

public final Group createGroup(java.lang.String root,
                               java.lang.String handler)
Create a new Group object. This operation must be requested to a specific µServer rather than being performed by application code, because resolution of the group classes depend on the contents of the class spaces associated to a particular µServer.

getSharedClassSpace

public ClassSpace getSharedClassSpace()
Retrieve the shared class space associated with the µServer containing the thread object invoking the method.

getPrivateClassSpace

public final ClassSpace getPrivateClassSpace()
Retrieves the private class space associated with the thread object invoking the method.

boot

public final void boot()
Start the run-time support listening for incoming groups.

shutDown

public final void shutDown()
Stop the run-time support listening for incoming groups.

getServer

public static final MuServer getServer()
Retrieve the µServer managing the thread object invoking this method. If the thread object is a stationary one, i.e. it has not been created as a consequence of a migration, the method returns null.

getServer

public static final MuServer getServer(java.lang.Thread t)
Retrieve the µServer managing the thread object passed as a parameter. If the thread object is a stationary one, i.e. it has not been created as a consequence of a migration, the method returns null.

getServer

public static final MuServer getServer(java.lang.Object obj)
Retrieve the µServer associated with the given object. If the object has not been inside a µServer, the method returns null.

run

public void run()
Implements the Runnable interface, and contains the behavior of the server.

Specified by:
run in interface java.lang.Runnable

cleanup

protected void cleanup()

M

void M(java.lang.String msg)
Output Message handling

D

void D(java.lang.String msg)

Err

void Err(java.lang.String msg)

D

void D(java.lang.String msg,
       java.lang.Throwable e)

Err

void Err(java.lang.String msg,
         java.lang.Throwable e)

parseHost

static java.net.InetAddress parseHost(java.lang.String destination)
                               throws java.net.UnknownHostException
Extracts the host component from an address specified as host:port.

parsePort

static int parsePort(java.lang.String destination)
              throws java.net.UnknownHostException
Extracts the port component from an address specified as host:port. If the port is not specified, the default value as specified in the class Properties is returned.

createClassLoader

protected MuClassLoader createClassLoader()
Overview  Package   Class  Use  Deprecated  Index 
Home >> All >> [ mucode overview ]  PREV CLASS  NEXT CLASS
SUMMARY: JavaDoc of mucode.MuServer JAVADOC | Sourc code of mucode.MuServer SOURCE | Download mucode.MuServer DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD