: Class StreamOutputActorImpl

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osl.manager.basic
Class StreamOutputActorImpl

java.lang.Object
  |
  +--java.lang.Thread
        |
        +--osl.manager.ActorImpl
              |
              +--osl.manager.basic.StreamOutputActorImpl

public class StreamOutputActorImpl
extends ActorImpl
implements StreamOutputActor

This class defines the implementation of an actor used to control an output stream on behalf of external actors. We require an implementation (rather than an Actor) because if a security manager is running (i.e. startfoundry was specified with the -secure option), then user-written actors will not have direct access to several standard streams (e.g. System.out). Since instances of ActorImpl are privileged they may control such streams and provide their services to specific actors. The methods exported to external actors is defined by the StreamOutputActor interface. In the current implementation, the first argument passed in the creation request for this actor is used to determine which output stream to manage. If the argument is "out", then System.out is managed. If the argument is "err", then System.err is managed. Otherwise, an error is returned by actorInitialize.

Version:: $Revision: 1.3 $ ($Date: 1999/01/19 18:43:34 $)
See Also:: osl.manager.basic.StreamOutputActor, Serialized Form

Field Summary
`protected WaitQueue`	`mailQueue` The queue which holds incoming requests.
`protected ActorManager`	`ourManager` The manager which manages this implementation.

Fields inherited from class osl.manager.ActorImpl

actorClass,  
classRef,  
context,  
extensionMethods,  
nextID,  
self

Fields inherited from class java.lang.Thread

MAX_PRIORITY,  
MIN_PRIORITY,  
NORM_PRIORITY

Constructor Summary
`StreamOutputActorImpl()`

Method Summary
`protected void`	`actorDeliver(ActorMsgRequest msg)` This method is called by a manager to deliver a new message to the local actor.
`protected void`	`actorInitialize(ActorManager ourMgr, ActorName you, ActorCreateRequest req)` This method is called by a manager to initialize an actor implementation after it is instantiated.
`protected void`	`actorPostMigrateRebuild(ActorManager ourMgr)` This method is called by the new manager of an actor implementation just after migration has occurred.
`void`	`close()` Close the internal output stream.
`void`	`flush()` Flush the internal output stream.
`protected ActorName`	`implCreate(ActorCreateRequest req)` Request a new actor to be created.
`protected void`	`implDestroy(java.lang.String reason)` Request to remove this actor from the system.
`protected java.lang.Object`	`implInvokeService(ServiceName name, java.lang.String meth, java.lang.Object[] args)` Request a service invocation on the named node service.
`protected void`	`implMigrate(ActorManagerName loc)` Request that this actor wishes to be migrated to a new location.
`protected java.lang.Object`	`implSend(ActorMsgRequest msg)` Request a message to be sent.
`void`	`print(java.lang.Object s)` Print an object representation to the output stream.
`void`	`print(java.lang.String s)` Print a string to the output stream.
`void`	`println(java.lang.Object s)` Print an object representation followed by a newline character.
`void`	`println(java.lang.String s)` Print a string followed by a newline character.
`void`	`run()` The main run loop for this implementation.
`void`	`write(java.lang.Byte[] b)` Write the contents of a byte array to the internal output stream.
`void`	`write(java.lang.Byte[] b, java.lang.Integer off, java.lang.Integer len)` Write a subsequence of a byte array to the output stream.
`void`	`write(java.lang.Integer b)` Writes a byte to the internal output stream.

Methods inherited from class osl.manager.ActorImpl

buildAsynchException, 
finalize, 
formatAsynchException, 
implExtension, 
mgrActorCreate, 
mgrActorFatalError, 
mgrActorInvokeService, 
mgrActorMigrate, 
mgrActorSend, 
registerExtension, 
removeExtension, 
setCreatingThread, 
stampRequest

Methods inherited from class java.lang.Thread

activeCount, 
checkAccess, 
countStackFrames, 
currentThread, 
destroy, 
dumpStack, 
enumerate, 
getContextClassLoader, 
getName, 
getPriority, 
getThreadGroup, 
interrupt, 
interrupted, 
isAlive, 
isDaemon, 
isInterrupted, 
join, 
join, 
join, 
resume, 
setContextClassLoader, 
setDaemon, 
setName, 
setPriority, 
sleep, 
sleep, 
start, 
stop, 
stop, 
suspend, 
toString, 
yield

Methods inherited from class java.lang.Object

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

Field Detail

ourManager

protected ActorManager ourManager

The manager which manages this implementation.

mailQueue

protected WaitQueue mailQueue

The queue which holds incoming requests.

Constructor Detail

StreamOutputActorImpl

public StreamOutputActorImpl()

Method Detail

actorInitialize

protected void actorInitialize(ActorManager ourMgr,
                               ActorName you,
                               ActorCreateRequest req)

This method is called by a manager to initialize an actor implementation after it is instantiated. The manager provides a reference to itself, a reference giving the name of the new actor, and a create request describing the new Actor that should be created and managed. After calling this method, a manager will call the run method in this class to start the actor executing. Note that the protection of this method prevents it from being called external to osl.manager. This was done to prevent arbitrary classes from initializing new actors. However, managers in different packages may invoke this method using implInitialize.

For this implementation, the manager reference and actor name are saved. The first constructor argument in the creation request is expected to be either the strint "out" or "err", indicating which System stream should be managed. An error is returned if no string is present.

Parameters:: ourMgr - The ActorManager which should be used by this actor implementation to invoke actor services.; you - The ActorName that should be used as the name of the new actor.; rtClass - The run-time Class of the user-written actor that should be instantiated by this implementation. This class will always be an extension of the Actor class.; initArgs - The array of arguments to pass to the constructor of the user-defined actor when it is instantiated.
Throws:: java.lang.RuntimeException - Thrown if no stream was specified in the first constructor argument.
Overrides:: actorInitialize in class ActorImpl
See Also:: ActorManager.implInitialize(osl.manager.ActorImpl, osl.manager.ActorName, osl.manager.ActorCreateRequest)

actorDeliver

protected void actorDeliver(ActorMsgRequest msg)

This method is called by a manager to deliver a new message to the local actor. This method is protected so that it has package level protection and therefore may not be invoked directly by user-written actor code.

For this implementation, we deposit the new message in our mail queue so that it can be processed in the main run loop.

Parameters:: msg - The ActorMsgRequest structure to be delivered. This structure must be maintained by the actor as it is required if an exception is returned to the manager.
Overrides:: actorDeliver in class ActorImpl

actorPostMigrateRebuild

protected void actorPostMigrateRebuild(ActorManager ourMgr)

This method is called by the new manager of an actor implementation just after migration has occurred. The implementation is expected to perform any re-initialization necessary after a migration (e.g. rebuilding transient fields). This method will be called before the implementations thread is restarted.

This method should never be called for this implementation as StreamOutputActorImpls will never migrate. If this method IS called for some reason then a runtime exception is thrown.

Parameters:: ourMgr - A reference to the new manager of the implementation after migration has occurred.
Throws:: java.lang.RuntimeException - Thrown if this method is ever called.
Overrides:: actorPostMigrateRebuild in class ActorImpl

implSend

protected java.lang.Object implSend(ActorMsgRequest msg)
                             throws RemoteCodeException

Request a message to be sent. The message argument is forwarded to the manager. If the RPC field of the message is set to true then the caller is blocked while the RPC takes place. This method is protected so that it has package level protection and therefore may not be invoked directly by user-written actor code.