ucb.util.mailbox

Class QueuedMailbox<Msg extends Serializable>

java.lang.Object

java.rmi.server.RemoteObject

java.rmi.server.RemoteServer

java.rmi.server.UnicastRemoteObject

ucb.util.mailbox.QueuedMailbox<Msg>

All Implemented Interfaces:

Serializable, Remote, Mailbox<Msg>

Direct Known Subclasses:

SinkBox

public class QueuedMailbox<Msg extends Serializable>
extends UnicastRemoteObject

A Mailbox with a specified (positive) capacity

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected int	capacity
protected int	depositBlocks
protected boolean	open
protected LinkedList<Msg>	queue

Fields inherited from class java.rmi.server.RemoteObject

ref

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QueuedMailbox(Class<Msg> msgClass, int capacity) A new QueuedMailbox with given CAPACITY carrying messages of type MSGCLASS.

Method Summary

Methods

Modifier and Type	Method and Description
int	capacity() The capacity (see interface comment above) of THIS.
<T extends Serializable> Mailbox<T>	checkType(Class<T> msgClass) Returns THIS, assuming that THIS conveys messages of class MSGCLASS.
void	close() Short for close (0).
void	close(long millis) Performs a flush(MILLIS) and then invalidates THIS for all future use, deleting all remaining messages.
static <Msg extends Serializable> QueuedMailbox<Msg>	create(Class<Msg> msgClass, int capacity) A new QueuedMailbox with capacity () fixed at CAPACITY.
static <Msg extends Serializable> QueuedMailbox<Msg>	create(int capacity) A new QueuedMailbox with capacity () fixed at CAPACITY, with no type checking.
void	deposit(Msg msg) Deposit MSG in this Mailbox.
boolean	deposit(Msg msg, long millis) Deposit MSG in this Mailbox, if this can be done within approximately MILLIS milliseconds.
protected void	enqueue(Msg msg) Place MSG at the end of the message queue.
boolean	flush(long millis) Wait for all queued messages to be received, or MILLIS milliseconds, whichever comes first.
protected void	forward(Msg msg, long millis) Perform forwarding of MSG to all recipients, waiting for up to MILLIS milliseconds for each deposit to be accepted.
void	forwardTo(List<Mailbox<Msg>> boxes) Forward copies of all messages (including any already present) to BOXES in the order received.
void	forwardTo(Mailbox<Msg> box) Forward copies of all messages (including any already present) to BOXES in the order received.
boolean	isClosed() True iff THIS is closed.
boolean	isForwarding() True iff THIS is currently forwarding messages as a result of forwardTo.
Class<Msg>	messageType() The (runtime) type of message sent through this box.
protected long	myWait(long limit) Wait for up to LIMIT milliseconds or the next notify or interrupt.
Msg	receive() Receive the next queued message in this Mailbox.
Msg	receive(long millis) Receive the next queued message in this Mailbox, if one is available within MILLIS milliseconds.
void	stopForwarding() Stop forwarding copies of messages.

Methods inherited from class java.rmi.server.UnicastRemoteObject

clone, exportObject, exportObject, exportObject, unexportObject

Methods inherited from class java.rmi.server.RemoteServer

getClientHost, getLog, setLog

Methods inherited from class java.rmi.server.RemoteObject

equals, getRef, hashCode, toString, toStub

Methods inherited from class java.lang.Object

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

Field Detail

queue

protected final LinkedList<Msg extends Serializable> queue

capacity

protected int capacity

open

protected boolean open

depositBlocks

protected int depositBlocks

Constructor Detail

QueuedMailbox

protected QueuedMailbox(Class<Msg> msgClass,
             int capacity)
                 throws RemoteException

A new QueuedMailbox with given CAPACITY carrying messages of type MSGCLASS. The factory method create, rather than this constructor, is intended for public use.

Throws:

RemoteException

Method Detail

create

public static <Msg extends Serializable> QueuedMailbox<Msg> create(Class<Msg> msgClass,
                                                   int capacity)

A new QueuedMailbox with capacity () fixed at CAPACITY.

create

public static <Msg extends Serializable> QueuedMailbox<Msg> create(int capacity)

A new QueuedMailbox with capacity () fixed at CAPACITY, with no type checking.

deposit

public void deposit(Msg msg)
             throws InterruptedException,
                    RemoteException

Deposit MSG in this Mailbox. If the Mailbox is full, wait if necessary for space to be available. MSG must be non-null. Throws Interrupted exception and does nothing if current thread is interrupted. Throws an IllegalStateException (or RemoteException) if THIS is closed. Throws IllegalArgumentException if MSG is null.

Throws:

InterruptedException

RemoteException

deposit

public boolean deposit(Msg msg,
              long millis)
                throws InterruptedException,
                       RemoteException

Deposit MSG in this Mailbox, if this can be done within approximately MILLIS milliseconds. Returns true iff the message was deposited. Does not block if MILLIS is 0. MSG must be non-null. Throws Interrupted exception and does nothing if current thread is interrupted. Throws IllegalStateException (or RemoteException) if THIS is closed. Throws IllegalArgumentException if MSG is null.

Throws:

InterruptedException

RemoteException

receive

public Msg receive()
                                 throws InterruptedException

Receive the next queued message in this Mailbox. Returns null if THIS is closed. Throws Interrupted exception and does nothing if the current thread is interrupted.

Throws:

InterruptedException

receive

public Msg receive(long millis)
                                 throws InterruptedException

Receive the next queued message in this Mailbox, if one is available within MILLIS milliseconds. Returns null otherwise, including if THIS is closed. Does not block if MILLIS is 0. Throws Interrupted exception and does nothing if current thread is interrupted.

Throws:

InterruptedException

forwardTo

public void forwardTo(Mailbox<Msg> box)
               throws InterruptedException,
                      RemoteException

Forward copies of all messages (including any already present) to BOXES in the order received. Once forwarded to all destinations, messages are otherwise treated as usual. Deposit blocks until all forwarding is complete.

Throws:

InterruptedException

RemoteException

forwardTo

public void forwardTo(List<Mailbox<Msg>> boxes)
               throws InterruptedException,
                      RemoteException

Forward copies of all messages (including any already present) to BOXES in the order received. Once forwarded to all destinations, messages are otherwise treated as usual. Deposit blocks until all forwarding is complete.

Throws:

InterruptedException

RemoteException

stopForwarding

public void stopForwarding()

Stop forwarding copies of messages.

flush

public boolean flush(long millis)
              throws InterruptedException

Wait for all queued messages to be received, or MILLIS milliseconds, whichever comes first. During this wait, the Mailbox acts as if full from the point of view of all threads attempting to deposit. Returns true if all messages were flushed within the time limit.

Throws:

InterruptedException

close

public void close(long millis)
           throws InterruptedException

Performs a flush(MILLIS) and then invalidates THIS for all future use, deleting all remaining messages. Any waiting threads or subsequent calls receive an immediate InvalidStateException indicating an invalid state. In general, the thread that uses a Mailbox to send messages is the one that closes it.

Throws:

InterruptedException

close

public void close()
           throws InterruptedException

Short for close (0).

Throws:

InterruptedException

isForwarding

public boolean isForwarding()

True iff THIS is currently forwarding messages as a result of forwardTo.

isClosed

public boolean isClosed()

True iff THIS is closed.

capacity

public int capacity()

The capacity (see interface comment above) of THIS.

enqueue

protected void enqueue(Msg msg)

Place MSG at the end of the message queue.

forward

protected void forward(Msg msg,
           long millis)
                throws RemoteException,
                       InterruptedException

Perform forwarding of MSG to all recipients, waiting for up to MILLIS milliseconds for each deposit to be accepted.

Throws:

RemoteException

InterruptedException

myWait

protected long myWait(long limit)
               throws InterruptedException

Wait for up to LIMIT milliseconds or the next notify or interrupt. Returns the remaining time.

Throws:

InterruptedException

messageType

public Class<Msg> messageType()

Description copied from interface: Mailbox

The (runtime) type of message sent through this box.

Specified by:

messageType in interface Mailbox<Msg extends Serializable>

checkType

public <T extends Serializable> Mailbox<T> checkType(Class<T> msgClass)

Description copied from interface: Mailbox

Returns THIS, assuming that THIS conveys messages of class MSGCLASS.

Specified by:

checkType in interface Mailbox<Msg extends Serializable>