com.ibm.aglets
Class AgletContextImpl

java.lang.Object
  com.ibm.aglets.AgletContextImpl

All Implemented Interfaces:

AgletContext

public final class AgletContextImpl

extends java.lang.Object

implements AgletContext

The AgletContextImpl class is the execution context for running aglets. It provides means for maintaining and managing running aglets in an environment where the aglets are protected from each other and the host system is secured against malicious aglets.

Version:

1.20 $Date: 2002/01/19 22:10:43 $

Author:

Danny B. Lange, Mitsuru Oshima, ONO Kouichi

Nested Class Summary

(package private) class

AgletContextImpl.EventRunner

Field Summary

private java.util.Hashtable	_agletProxies
(package private) java.util.Properties	_contextProperties
private java.net.URL	_hostingURL
private java.lang.String	_name
private Persistence	_persistence
private ResourceManagerFactory	_rm_factory
private boolean	_secure
(package private) SubscriberManager	_subscriberManager
(package private) AgletTimer	_timer
private static ContextPermission	ADD_LISTENER_PERMISSION
private java.util.Hashtable	clips
(package private) AgletID	context_aid
private int	creating
private java.lang.Object	creationLock
(package private) AgletContextImpl.EventRunner	erunner
private java.util.Hashtable	images
(package private) ContextListener	listeners
private static LogCategory	logCategory
private static ContextPermission	REMOVE_LISTENER_PERMISSION
private static ContextPermission	SHUTDOWN_PERMISSION
private boolean	shutting_down
private static ContextPermission	START_PERMISSION

Constructor Summary

(package private)	AgletContextImpl(java.lang.String name) Creates an execution context for aglets.
(package private)	AgletContextImpl(java.lang.String name, boolean secure)

Method Summary

(package private) void	addAgletProxy(AgletID aid, AgletProxyImpl proxy)
void	addContextListener(ContextListener o) Adds the specified context listener to receive context events from this context.
(package private) void	checkPermission(java.security.Permission p)
void	clearCache(java.net.URL codebase) Clear the cache
private AgletProxy	createAglet(java.net.URL url, java.lang.String classname, java.security.cert.Certificate owner, java.lang.Object init) Creates an instance of the specified aglet located at the specified URL.
AgletProxy	createAglet(java.net.URL url, java.lang.String classname, java.lang.Object init) Creates an instance of the specified aglet located at the specified URL.
(package private) ResourceManager	createResourceManager(java.net.URL codebase, java.security.cert.Certificate owner, ClassName[] table)
(package private) void	endCreation()
java.util.Enumeration	getAgletProxies() Gets the aglet proxies in the current execution context.
java.util.Enumeration	getAgletProxies(int type) Gets the aglet proxies in the current execution context.
AgletProxy	getAgletProxy(AgletID aid) Gets the proxy for an aglet specified by its identity.
AgletProxy	getAgletProxy(java.net.URL host, AgletID aid) Deprecated.
java.applet.AudioClip	getAudioClip(java.net.URL url) Gets an audio clip.
java.net.URL	getHostingURL() Returns the URL of the daemon serving all current execution contexts.
java.awt.Image	getImage(ImageData d) Gets an image.
java.awt.Image	getImage(java.net.URL url) Gets an image.
ImageData	getImageData(java.net.URL url) Gets an image data.
java.lang.String	getName() Gets the name of the context
Persistence	getPersistence()
java.lang.Object	getProperty(java.lang.String key) Gets the context property indicated by the key.
java.lang.Object	getProperty(java.lang.String key, java.lang.Object def) Gets the context property indicated by the key and default value.
ResourceManagerFactory	getResourceManagerFactory()
(package private) boolean	getSecurity()
(package private) java.lang.Object	handleMessage(Message msg)
(package private) void	log(java.lang.String kind, java.lang.String msg)
ReplySet	multicastMessage(Message msg) Sends a multicast message to the subscribers in the context.
(package private) boolean	noResponseAglet(AgletProxy proxy)
void	postEvent(ContextEvent event, boolean sync)
void	postEvent0(ContextEvent event)
void	receiveAglet(Name agent_name, ClassName[] classnames, java.lang.String codebase, byte[] agent, java.lang.String sender) Receives an aglet.
(package private) void	removeAgletProxy(AgletID aid, AgletProxyImpl proxy)
void	removeContextListener(ContextListener o) Removes the specified context listener.
AgletProxy	retractAglet(Ticket ticket, AgletID aid)
AgletProxy	retractAglet(java.net.URL url) Deprecated.
AgletProxy	retractAglet(java.net.URL url, AgletID aid) Retracts the Aglet specified by its url: scheme://host-domain-name/[user-name]#aglet-identity.
void	setPersistence(Persistence p)
void	setProperty(java.lang.String key, java.lang.Object value) Sets the context property
void	setResourceManagerFactory(ResourceManagerFactory rmf)
(package private) void	setSecurity(boolean secure)
void	showDocument(java.net.URL url) Shows a new document.
void	shutdown() Shutdown the context.
void	shutdown(Message msg) Shutdown the context with the specific message object.
void	start() Starts
void	start(boolean reactivate) Starts the context.
(package private) void	startCreation()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logCategory

private static LogCategory logCategory

_secure

private boolean _secure

START_PERMISSION

private static ContextPermission START_PERMISSION

SHUTDOWN_PERMISSION

private static ContextPermission SHUTDOWN_PERMISSION

ADD_LISTENER_PERMISSION

private static ContextPermission ADD_LISTENER_PERMISSION

REMOVE_LISTENER_PERMISSION

private static ContextPermission REMOVE_LISTENER_PERMISSION

_hostingURL

private java.net.URL _hostingURL

_name

private java.lang.String _name

_persistence

private Persistence _persistence

_agletProxies

private java.util.Hashtable _agletProxies

_contextProperties

java.util.Properties _contextProperties

_subscriberManager

SubscriberManager _subscriberManager

_rm_factory

private ResourceManagerFactory _rm_factory

_timer

AgletTimer _timer

creationLock

private java.lang.Object creationLock

creating

private int creating

shutting_down

private boolean shutting_down

context_aid

AgletID context_aid

listeners

ContextListener listeners

erunner

AgletContextImpl.EventRunner erunner

images

private java.util.Hashtable images

clips

private java.util.Hashtable clips

Constructor Detail

AgletContextImpl

AgletContextImpl(java.lang.String name)

Creates an execution context for aglets.

AgletContextImpl

AgletContextImpl(java.lang.String name,
                 boolean secure)

Method Detail

addAgletProxy

void addAgletProxy(AgletID aid,
                   AgletProxyImpl proxy)
             throws InvalidAgletException

Throws:

InvalidAgletException

addContextListener

public void addContextListener(ContextListener o)

Description copied from interface: AgletContext

Adds the specified context listener to receive context events from this context.

Specified by:

addContextListener in interface AgletContext

Parameters:

o - the context listener

checkPermission

void checkPermission(java.security.Permission p)

clearCache

public void clearCache(java.net.URL codebase)

Clear the cache

Specified by:

clearCache in interface AgletContext

Parameters:

codebase - the codebase of the cache to clean up. if null, entire cache in this context is cleared.

createAglet

public AgletProxy createAglet(java.net.URL url,
                              java.lang.String classname,
                              java.lang.Object init)
                       throws java.io.IOException,
                              AgletException,
                              java.lang.ClassNotFoundException,
                              java.lang.InstantiationException

Creates an instance of the specified aglet located at the specified URL.

Specified by:

createAglet in interface AgletContext

Parameters:

url - the URL to load the aglet class from.

classname - code gives the name of the file that contains the aglet's compiled class code. This file is relative to the base URL of the aglet, and cannot be absolute.

init - init is an object passed on to the aglet's onCreation method.

Returns:

a newly instantiated and initialized Aglet.

Throws:

java.lang.ClassNotFoundException - if the class was not found

java.lang.InstantiationException - if failed to instantiate the Aglet.

AgletException - if the aglets can not be created.

java.io.IOException

See Also:

Aglet.onCreation(java.lang.Object)

createAglet

private AgletProxy createAglet(java.net.URL url,
                               java.lang.String classname,
                               java.security.cert.Certificate owner,
                               java.lang.Object init)
                        throws java.io.IOException,
                               AgletException,
                               java.lang.ClassNotFoundException,
                               java.lang.InstantiationException

Creates an instance of the specified aglet located at the specified URL.

Parameters:

url - the URL to load the aglet class from.

Returns:

a newly instantiated and initialized Aglet.

Throws:

java.lang.ClassNotFoundException - if the class was not found

java.lang.InstantiationException - if failed to instantiate the Aglet.

java.io.IOException

AgletException

createResourceManager

ResourceManager createResourceManager(java.net.URL codebase,
                                      java.security.cert.Certificate owner,
                                      ClassName[] table)

endCreation

void endCreation()

getAgletProxies

public java.util.Enumeration getAgletProxies()

Gets the aglet proxies in the current execution context.

Specified by:

getAgletProxies in interface AgletContext

Returns:

an enumeration of aglet proxies.

getAgletProxies

public java.util.Enumeration getAgletProxies(int type)

Gets the aglet proxies in the current execution context.

Specified by:

getAgletProxies in interface AgletContext

Parameters:

type - the type of aglets. ACTIVE, INACTIVE or ACTIVE | INACTIVE,

Returns:

an enumeration of aglet proxies.

See Also:

Aglet.ACTIVE, Aglet.INACTIVE

getAgletProxy

public AgletProxy getAgletProxy(AgletID aid)

Gets the proxy for an aglet specified by its identity.

Specified by:

getAgletProxy in interface AgletContext

Parameters:

aid - the identity of the aglet.

Returns:

the aglet proxy.

getAgletProxy

public AgletProxy getAgletProxy(java.net.URL host,
                                AgletID aid)

Deprecated.

Gets the proxy for a remote aglet specified by url

Specified by:

getAgletProxy in interface AgletContext

Parameters:

aid - the identity of the aglet.

host - the address specifing a remote context.

Returns:

the aglet proxy

See Also:

getName

getAudioClip

public java.applet.AudioClip getAudioClip(java.net.URL url)

Description copied from interface: AgletContext

Gets an audio clip.

Specified by:

getAudioClip in interface AgletContext

Parameters:

url - an absolute URL giving the location of the audio file.

Returns:

the Audio clip object give by the URL.

getHostingURL

public java.net.URL getHostingURL()

Returns the URL of the daemon serving all current execution contexts.

Specified by:

getHostingURL in interface AgletContext

Returns:

the URL of the daemon. null if the hosting information is not available.

Throws:

AgletException - if the hosting URL cannot be determined.

getImage

public java.awt.Image getImage(ImageData d)

Description copied from interface: AgletContext

Gets an image. This is a tempolary solution.

Specified by:

getImage in interface AgletContext

Parameters:

d - a serializable image data.

Returns:

the image object converted from the image data.

getImage

public java.awt.Image getImage(java.net.URL url)

Description copied from interface: AgletContext

Gets an image.

Specified by:

getImage in interface AgletContext

Parameters:

url - an absolute URL giving the location of the image file.

Returns:

the image object give by the URL.

getImageData

public ImageData getImageData(java.net.URL url)

Description copied from interface: AgletContext

Gets an image data. This is a tempolary solution.

Specified by:

getImageData in interface AgletContext

Parameters:

url - an absolute URL giving the location of the image file.

Returns:

the serializable image data.

getName

public java.lang.String getName()

Gets the name of the context

Specified by:

getName in interface AgletContext

Returns:

the name of the context

getPersistence

public Persistence getPersistence()
                           throws java.io.IOException

Throws:

java.io.IOException

getProperty

public java.lang.Object getProperty(java.lang.String key)

Gets the context property indicated by the key.

Specified by:

getProperty in interface AgletContext

Parameters:

key - the name of the context property.

Returns:

the value of the specified key.

getProperty

public java.lang.Object getProperty(java.lang.String key,
                                    java.lang.Object def)

Gets the context property indicated by the key and default value.

Specified by:

getProperty in interface AgletContext

Parameters:

key - the name of the context property.

def - the value to use if this property is not set.

Returns:

the value of the specified key.

getResourceManagerFactory

public ResourceManagerFactory getResourceManagerFactory()

getSecurity

boolean getSecurity()

handleMessage

java.lang.Object handleMessage(Message msg)
                         throws NotHandledException,
                                MessageException

Throws:

NotHandledException

MessageException

log

void log(java.lang.String kind,
         java.lang.String msg)

multicastMessage

public ReplySet multicastMessage(Message msg)

Description copied from interface: AgletContext

Sends a multicast message to the subscribers in the context.

Specified by:

multicastMessage in interface AgletContext

Returns:

ReplySet containing FutureReplies

noResponseAglet

boolean noResponseAglet(AgletProxy proxy)

postEvent

public void postEvent(ContextEvent event,
                      boolean sync)

postEvent0

public void postEvent0(ContextEvent event)

receiveAglet

public void receiveAglet(Name agent_name,
                         ClassName[] classnames,
                         java.lang.String codebase,
                         byte[] agent,
                         java.lang.String sender)
                  throws AgletException,
                         java.lang.ClassNotFoundException

Receives an aglet. Will start the aglet and return its proxy.

Throws:

AgletException - if it is not received.

java.lang.ClassNotFoundException

removeAgletProxy

void removeAgletProxy(AgletID aid,
                      AgletProxyImpl proxy)

removeContextListener

public void removeContextListener(ContextListener o)

Description copied from interface: AgletContext

Removes the specified context listener.

Specified by:

removeContextListener in interface AgletContext

Parameters:

o - the context listener

retractAglet

public AgletProxy retractAglet(Ticket ticket,
                               AgletID aid)
                        throws java.io.IOException,
                               AgletException

Throws:

java.io.IOException

AgletException

retractAglet

public AgletProxy retractAglet(java.net.URL url)
                        throws java.io.IOException,
                               AgletException

Deprecated.

Retracts the Aglet specified by its url: scheme://host-domain-name/[user-name]#aglet-identity.

Specified by:

retractAglet in interface AgletContext

Parameters:

url - the location and aglet identity of the aglet to be retracted.

Returns:

the aglet proxy for the retracted aglet.

Throws:

AgletException - when the method failed to retract the aglet.

java.io.IOException

retractAglet

public AgletProxy retractAglet(java.net.URL url,
                               AgletID aid)
                        throws java.io.IOException,
                               AgletException

Retracts the Aglet specified by its url: scheme://host-domain-name/[user-name]#aglet-identity.

Specified by:

retractAglet in interface AgletContext

Parameters:

url - the location and aglet identity of the aglet to be retracted.

aid - the aglet identity of the aglet to be retracted.

Returns:

the aglet proxy for the retracted aglet.

Throws:

AgletException - when the method failed to retract the aglet.

java.io.IOException

setPersistence

public void setPersistence(Persistence p)
                    throws AgletException

Throws:

AgletException

setProperty

public void setProperty(java.lang.String key,
                        java.lang.Object value)

Sets the context property

Specified by:

setProperty in interface AgletContext

Parameters:

key - the name of the context property.

value - the value to be stored.

Returns:

the value of the specified key.

setResourceManagerFactory

public void setResourceManagerFactory(ResourceManagerFactory rmf)

setSecurity

void setSecurity(boolean secure)

showDocument

public void showDocument(java.net.URL url)

Shows a new document. This may be ignored by the aglet context. ContextPermission("showDocument", url) is required.

Specified by:

showDocument in interface AgletContext

Parameters:

url - an url to be shown

shutdown

public void shutdown()

Description copied from interface: AgletContext

Shutdown the context. This is ignored if the context is already stopped.

Specified by:

shutdown in interface AgletContext

See Also:

start

shutdown

public void shutdown(Message msg)

Description copied from interface: AgletContext

Shutdown the context with the specific message object. This message object is delivered to all aglets in the context before all aglets are killed. This is ignored if the context is already stopped.

Specified by:

shutdown in interface AgletContext

See Also:

start

start

public void start()

Starts

Specified by:

start in interface AgletContext

start

public void start(boolean reactivate)

Description copied from interface: AgletContext

Starts the context. This is ignored if the context is already runnig.

Specified by:

start in interface AgletContext

Parameters:

reactivate - if false, it does not activate aglets in the deactivation spool

startCreation

void startCreation()
             throws ShuttingDownException

Throws:

ShuttingDownException