mChaRM.multichannel
Class channelCore

java.lang.Object
  |
  +--uka.karmi.rmi.server.RemoteObject
        |
        +--uka.karmi.rmi.server.UnicastRemoteObject
              |
              +--mChaRM.multichannel.channelCore

All Implemented Interfaces:

channelInterface, java.lang.Cloneable, uka.karmi.rmi.Remote

Direct Known Subclasses:

normalChannel, RMPChannel, validationChannel, verboseChannel

public class channelCore

extends uka.karmi.rmi.server.UnicastRemoteObject

implements channelInterface

This class defines how multi-channels behave (by default) in the abstract locus. Any other kind of multi-channel can be derived from this class. The key issue consists in overriding the coreMetaBehavior method.

Remember each multi-channel is identified by its kind, ie., the reflective behaviour it realizes, and by the set of objects -- playing the role of receivers -- which it is connected to.

Since:

Version 1.0

Version:

1.5

Author:

Walter Cazzola (cazzola@disi.unige.it)

Fields inherited from class uka.karmi.rmi.server.RemoteObject

serverRef

Constructor Summary

channelCore(java.lang.String kind, java.lang.String[] RsName, java.lang.String SSClassName, java.lang.String RSClassName)
constructor of multi-channels.

Method Summary

java.lang.Object	coreMetaBehavior(mChaRMMethodCall msg) This method embodies the reflective behaviour realized by the multi-channel.
int	howManyReceivers() returns the number of receivers bound to this multi-channel.
int	howManySenders() returns the number of senders bound to this multi-channel, at the moment of the call.
java.lang.String	kind() returns the kind of the multi-channel.
java.lang.String	receiverName(int indx) returns the name of the receiver whose position is specified by indx.
receiverStubInterface	receiverStub(java.lang.String name)
receiverStubInterface	receiverStubByPosition(int indx)
java.lang.String	receiverStubClassName()
java.lang.Object	retrieveReceiverFieldValue(java.lang.String receiverName, java.lang.String fieldName) retrieves the content of a field of the specified receiver.
java.lang.Object	retrieveSenderFieldValue(java.lang.String senderName, java.lang.String fieldName) retrieves the content of a field of the specified sender.
java.lang.String	senderName(int indx) returns the name of the sender whose position is specified by indx.
senderStubInterface	senderStub(java.lang.String name)
senderStubInterface	senderStubByPosition(int indx)
java.lang.String	senderStubClassName()
void	senderStubHasBeenCreated(java.lang.String senderStubName) the invocation of this method allows to connect the multi-channel to the new stub.
void	setKind(java.lang.String k) sets the kind of the multi-channel to the passed value k.
void	setReceiverName(int indx, java.lang.String name) inserts the name of a receiver at the position specified by indx.
void	setReceiverStub(java.lang.String name, receiverStubInterface RSI)
void	setReceiverStubClassName(java.lang.String name)
void	setRsName(java.lang.String[] names) uses the array of strings specified by name as the set of names of the receivers of the multi-channel.
void	setSenderName(int indx, java.lang.String name) inserts the name of a sender at the position specified by indx.
void	setSenderStub(java.lang.String name, senderStubInterface SSI)
void	setSenderStubClassName(java.lang.String name)
java.lang.String	supplyASenderStub() on request, it supplies the class name of its senderStub to the requiring client.

Methods inherited from class uka.karmi.rmi.server.UnicastRemoteObject

buildStub, clone, exportObject, exportObject, unexportObject

Methods inherited from class uka.karmi.rmi.server.RemoteObject

equals, hashCode, toString, toStub

Methods inherited from class java.lang.Object

, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

channelCore

public channelCore(java.lang.String kind,
                   java.lang.String[] RsName,
                   java.lang.String SSClassName,
                   java.lang.String RSClassName)
            throws uka.karmi.rmi.RemoteException,
                   ReceiverStubNotFoundException

constructor of multi-channels. This constructor creates and registers as server the core of a multi-channel of kind: kind. The core is registered using the following string: "__"+kind+"{ "rec₁+" "+rec₂ ... +rec_n+" }" then, it instructs each receivers to create and to register as server their stubs. The stub of the receiver rec_i is registered as: "__"+kind+"{ "rec₁+" "+rec₂ ... +rec_n+" }"+"__"+rec_i finally the core connect itself with its stubs on the receivers site.

Parameters:

kind - a String representing the multi-channel's behavior.

RsName - an Array of Strings representing the name of the receivers, which it is connected to.

SSClassName - a String specifying the class of the stubs that will be attached to the multi-channel senders.

RSClassName - a String specifying the class of the stubs that will be attached to the multi-channel receivers.

Throws:

ReceiverStubNotFoundException - thrown when one of the specified receiver wasn't started before the core.

Method Detail

kind

public java.lang.String kind()

returns the kind of the multi-channel.

Returns:

the kind of the multi-channel.

setKind

public final void setKind(java.lang.String k)

sets the kind of the multi-channel to the passed value k.

Parameters:

k - the kind of the multi-channel.

receiverName

public final java.lang.String receiverName(int indx)

returns the name of the receiver whose position is specified by indx. The position is related to how the names are stored. At the moment this method can be used consistently only in conjunction with loop statements.

Parameters:

indx - the index of the position.

Returns:

the name of the receiver.

setReceiverName

public final void setReceiverName(int indx,
                                  java.lang.String name)

inserts the name of a receiver at the position specified by indx. The method doesn't check if the slot is already used.
Note that you have to keep the set of the name alphabetically sorted in order to allow the core to connect to its stubs and vice versa.

Parameters:

indx - the index of the position.

name - the name of the receiver.

setRsName

public final void setRsName(java.lang.String[] names)

uses the array of strings specified by name as the set of names of the receivers of the multi-channel. It also sorts the array.

Parameters:

names - a set of names.

howManyReceivers

public final int howManyReceivers()

returns the number of receivers bound to this multi-channel. The number of receivers is a quantities fixed at compile-time and depends on the kinds statement.

Returns:

the number of receivers.

senderName

public final java.lang.String senderName(int indx)
                                  throws java.lang.ArrayIndexOutOfBoundsException

returns the name of the sender whose position is specified by indx. The position is related to how the names are stored. At the moment this method can be used consistently only in conjunction with loop statements.

Parameters:

indx - the index of the position.

Returns:

the name of the sender.

Throws:

java.lang.ArrayIndexOutOfBoundsException - thrown when the index passed is too big with respect to the number of the senders.

setSenderName

public final void setSenderName(int indx,
                                java.lang.String name)
                         throws java.lang.ArrayIndexOutOfBoundsException

inserts the name of a sender at the position specified by indx. The method doesn't check if the slot is already used. The method provides to append a new sender to the tail when the current number of sender is passed as index.

Parameters:

indx - the index of the position.

name - the name of the receiver.

howManySenders

public final int howManySenders()

returns the number of senders bound to this multi-channel, at the moment of the call. The number of senders is zero at the core creation and increase during the execution with the calls the core has to process.

Returns:

the number of senders.

receiverStub

public final receiverStubInterface receiverStub(java.lang.String name)

receiverStubByPosition

public final receiverStubInterface receiverStubByPosition(int indx)

setReceiverStub

public final void setReceiverStub(java.lang.String name,
                                  receiverStubInterface RSI)

senderStub

public final senderStubInterface senderStub(java.lang.String name)

senderStubByPosition

public final senderStubInterface senderStubByPosition(int indx)

setSenderStub

public final void setSenderStub(java.lang.String name,
                                senderStubInterface SSI)

receiverStubClassName

public final java.lang.String receiverStubClassName()

setReceiverStubClassName

public final void setReceiverStubClassName(java.lang.String name)

senderStubClassName

public final java.lang.String senderStubClassName()

setSenderStubClassName

public final void setSenderStubClassName(java.lang.String name)

coreMetaBehavior

public java.lang.Object coreMetaBehavior(mChaRMMethodCall msg)
                                  throws MethodDoesNotExistException,
                                         uka.karmi.rmi.RemoteException

This method embodies the reflective behaviour realized by the multi-channel. This method performs meta-computations on the reified method call: multiRMI(RsName, methodName, args) the computations performed can't make assumption about where their are performed.
This method must be overrode in order to implement new kind of multi-channels.

as default behavior, it delivers the message to the specified receivers, collects the results and returns the result of the computation of the first receiver to the sender. Note that receivers can be a subset of the multi-channel's receivers

Specified by:

coreMetaBehavior in interface channelInterface

Parameters:

msg - the hijacked method call.

Returns:

the result of the method call.

Throws:

MethodDoesNotExistException - thrown when the method reified doesn't exist in the referent class.

retrieveSenderFieldValue

public java.lang.Object retrieveSenderFieldValue(java.lang.String senderName,
                                                 java.lang.String fieldName)
                                          throws SenderStubNotFoundException,
                                                 FieldDoesNotExistException,
                                                 uka.karmi.rmi.RemoteException

retrieves the content of a field of the specified sender.

Parameters:

senderName - the name of the sender the core questions about the content of its field

fieldName - the name of the field we want to inspect.

Returns:

the content of the inspected field.

Throws:

SenderStubNotFoundException - thrown when the sender is unreacheable.

FieldDoesNotExistException - thrown when the class of the sender doesn't define the field passed.

retrieveReceiverFieldValue

public java.lang.Object retrieveReceiverFieldValue(java.lang.String receiverName,
                                                   java.lang.String fieldName)
                                            throws ReceiverStubNotFoundException,
                                                   FieldDoesNotExistException,
                                                   uka.karmi.rmi.RemoteException

retrieves the content of a field of the specified receiver.

Parameters:

receiverName - the name of the receiver the core questions about the content of its field

fieldName - the name of the field we want to inspect.

Returns:

the content of the inspected field.

Throws:

ReceiverStubNotFoundException - thrown when the receiver is unreacheable.

FieldDoesNotExistException - thrown when the class of the sender doesn't define the field passed.

supplyASenderStub

public final java.lang.String supplyASenderStub()
                                         throws uka.karmi.rmi.RemoteException

on request, it supplies the class name of its senderStub to the requiring client. when a sender needs that one of its computation be reified by a multi-channel it looks for a sender stub of such multi-channel. This method cannot be overrode nor used directly by users. returns: the class name of its senderStub.

Specified by:

supplyASenderStub in interface channelInterface

senderStubHasBeenCreated

public final void senderStubHasBeenCreated(java.lang.String senderStubName)
                                    throws SenderStubNotFoundException

the invocation of this method allows to connect the multi-channel to the new stub. This method cannot be overrode nor used directly by users.

Specified by:

senderStubHasBeenCreated in interface channelInterface

Parameters:

senderStubName - the name of the stub, who the multi-channel have to connect to.

Throws:

SenderStubNotFoundException - thrown when the senderStub is not ready to be linked to the core.