edu.ucdavis.rj

Class OpProxy

java.lang.Object

edu.ucdavis.rj.OpProxy

All Implemented Interfaces:

Op, java.io.Serializable

public class OpProxy
extends java.lang.Object
implements java.io.Serializable, Op

An OpProxy acts like a capability in JR or SR terms. Its methods are delegated to the remote object. To get an OpProxy for an OpRemote f, just use new OpProxy(f).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
OpProxy(OpRemote impl)

Method Summary

Modifier and Type	Method and Description
Invocation	call() Invoke this operation synchronously.
Invocation	call(Invocation inv) Invoke this operation synchronously.
boolean	canAppearInInni() Can this operation be serviced by an inni? Only an OpInni can.
void	deliverPendingMessages() If operation's queue of pending invocations was locked due to equivalence class locking stuff (e.g., merging), then deliver pending messages.
edu.ucdavis.rj.OpInniIterator	elements() Get an iterator to iterate over pending invocations of this operation.
boolean	equals(java.lang.Object other) Two OpProxys are equal if their OpRemotes are.
long	getFirstTime() Get the timestamp of the first (oldest) pending invocation of this operation.
java.lang.String	getId() Returns unique identifier for this operation.
edu.ucdavis.rj.InLock	getLock() Get the equivalence class lock for this operation.
OpRemote	getOpRemote() Access method to return proxy's implementation.
int	hashCode() // force hashing to use equals.
boolean	isNoop() Determines whether this operation is a noop.
boolean	isRemote(java.lang.String site) Is this operation on a remote VM or on the current VM? (Not allowed on an OpMethod.)
int	length() Returns the number of Invocations pending for this operation.
Invocation	P() A semaphore P (aka down) operation.
Invocation	receive() Get the first (oldest) pending invocation of this OpInni.
void	send() Invoke this operation asynchronously.
void	send(Invocation inv) Invoke this operation asynchronously.
void	V() A semaphore V (aka up) operation.

Methods inherited from class java.lang.Object

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

Constructor Detail

OpProxy

public OpProxy(OpRemote impl)

Method Detail

getOpRemote

public OpRemote getOpRemote()

Access method to return proxy's implementation.

Returns:

This proxy's OpRemote implementation.

getId

public java.lang.String getId()
                       throws java.rmi.RemoteException

Description copied from interface: Op

Returns unique identifier for this operation.

Specified by:

getId in interface Op

Returns:

that id.

Throws:

java.rmi.RemoteException - if RMI fails.

isNoop

public boolean isNoop()
               throws java.rmi.RemoteException

Description copied from interface: Op

Determines whether this operation is a noop.

Specified by:

isNoop in interface Op

Returns:

true if and only if this operation is a noop.

Throws:

java.rmi.RemoteException - if RMI fails.

getFirstTime

public long getFirstTime()
                  throws java.rmi.RemoteException

Description copied from interface: Op

Get the timestamp of the first (oldest) pending invocation of this operation.

Specified by:

getFirstTime in interface Op

Returns:

that timestamp.

Throws:

java.rmi.RemoteException - if this Op is an OpMethod.

canAppearInInni

public boolean canAppearInInni()
                        throws java.rmi.RemoteException

Description copied from interface: Op

Can this operation be serviced by an inni? Only an OpInni can.

Specified by:

canAppearInInni in interface Op

Returns:

true if and only if this operation is an OpInni.

Throws:

java.rmi.RemoteException - if RMI fails.

getLock

public edu.ucdavis.rj.InLock getLock()
                              throws java.rmi.RemoteException

Description copied from interface: Op

Get the equivalence class lock for this operation. (Not allowed on an OpMethod.)

Specified by:

getLock in interface Op

Returns:

that lock.

Throws:

java.rmi.RemoteException - if RMI fails.

isRemote

public boolean isRemote(java.lang.String site)
                 throws java.rmi.RemoteException

Description copied from interface: Op

Is this operation on a remote VM or on the current VM? (Not allowed on an OpMethod.)

Specified by:

isRemote in interface Op

Parameters:

site - machine name.

Returns:

true if and only if this operation is remote.

Throws:

java.rmi.RemoteException - if RMI fails.

deliverPendingMessages

public void deliverPendingMessages()
                            throws java.rmi.RemoteException

Description copied from interface: Op

If operation's queue of pending invocations was locked due to equivalence class locking stuff (e.g., merging), then deliver pending messages.

Specified by:

deliverPendingMessages in interface Op

Throws:

java.rmi.RemoteException - if this Op is an OpMethod.

elements

public edu.ucdavis.rj.OpInniIterator elements()
                                       throws java.rmi.RemoteException

Description copied from interface: Op

Get an iterator to iterate over pending invocations of this operation.

Specified by:

elements in interface Op

Returns:

that iterator.

Throws:

java.rmi.RemoteException - if this Op is an OpMethod.

send

public void send(Invocation inv)
          throws java.rmi.RemoteException

Description copied from interface: Op

Invoke this operation asynchronously.

Specified by:

send in interface Op

Parameters:

inv - The invocation to service.

Throws:

java.rmi.RemoteException - if RMI fails.

send

public void send()
          throws java.rmi.RemoteException

Description copied from interface: Op

Invoke this operation asynchronously. Abbreviation for this.send (new Invocation(...)); See Op.send(edu.ucdavis.rj.Invocation).

Specified by:

send in interface Op

Throws:

java.rmi.RemoteException - if RMI fails.

V

public void V()
       throws java.rmi.RemoteException

Description copied from interface: Op

A semaphore V (aka up) operation. Intended for use on OpInni's semaphore operations.

Specified by:

V in interface Op

Throws:

java.rmi.RemoteException - if RMI fails.

call

public Invocation call(Invocation inv)
                throws java.rmi.RemoteException

Description copied from interface: Op

Invoke this operation synchronously.

Specified by:

call in interface Op

Parameters:

inv - The invocation to service.

Returns:

The invocation, from which the return value of the operation can be extracted.

N.B., (the reference for) the returned invocation might not be the same as inv. For example, do NOT use, e.g., Invocation inv = new Invocation(...); thefun.call(inv); System.out.println(inv.getReturnValue()); because inv's value after the call will be the same as its value before the call, and inv.getReturnValue() will likely be null. Instead, in this example, use inv = thefun.call(inv);.

Throws:

java.rmi.RemoteException - if RMI fails.

call

public Invocation call()
                throws java.rmi.RemoteException

Description copied from interface: Op

Invoke this operation synchronously. Abbreviation for this.call (new Invocation(...)); See Op.call(edu.ucdavis.rj.Invocation).

Specified by:

call in interface Op

Returns:

The first pending invocation.

Throws:

java.rmi.RemoteException - if RMI fails.

receive

public Invocation receive()
                   throws java.rmi.RemoteException

Description copied from interface: Op

Get the first (oldest) pending invocation of this OpInni. Wait if no invocation is pending. (Not allowed on an OpMethod.)

Specified by:

receive in interface Op

Returns:

The first pending invocation.

Throws:

java.rmi.RemoteException - if this Op is an OpMethod.

P

public Invocation P()
             throws java.rmi.RemoteException

Description copied from interface: Op

A semaphore P (aka down) operation. Intended for use on OpInni's semaphore operations. (Not allowed on an OpMethod.)

Specified by:

P in interface Op

Returns:

The first pending invocation.

Throws:

java.rmi.RemoteException - if this Op is an OpMethod.

length

public int length()
           throws java.rmi.RemoteException

Description copied from interface: Op

Returns the number of Invocations pending for this operation.

Specified by:

length in interface Op

Returns:

The number of pending Invocations.

Throws:

java.rmi.RemoteException - if RMI fails.

equals

public boolean equals(java.lang.Object other)

Two OpProxys are equal if their OpRemotes are. An OpProxy equals an OpRemote if the OpProxy's impl is the OpRemote. Consistent with other equals (e.g. String.equals, return false for null or a non-OpProxy and non-OpRemote object.

Overrides:

equals in class java.lang.Object

Parameters:

other - The other Object to compare.

Returns:

true if and only if equal.

hashCode

public int hashCode()

// force hashing to use equals. // not good for performance, but hard to discriminate between // values of OpProxy. // (Could give each one an Id, like OpImpl's id, just for this purpose.) /////////// reconsider this later... public int hashCode() { return 9999; }

Overrides:

hashCode in class java.lang.Object