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NSConnection class reference

Authors

Andrew Kachites McCallum (mccallum@gnu.ai.mit.edu)
Richard Frith-Macdonald (rfm@gnu.org)

Version: 35728

Date: 2012-10-20 22:11:26 +0100 (Sat, 20 Oct 2012)

Copyright: (C) 1994, 1995, 1996, 1997, 2000 Free Software Foundation, Inc.


Contents -

  1. Software documentation for the NSConnection class
  2. Software documentation for the NSObject(NSConnectionDelegate) informal protocol

Software documentation for the NSConnection class

NSConnection : NSObject

Declared in:
Foundation/NSConnection.h
Availability: OpenStep

NSConnection objects are used to manage communications between objects in different processes, in different machines, or in different threads.
Method summary

allConnections 

+ (NSArray*) allConnections;
Availability: OpenStep

Returns an array containing all the NSConnection objects known to the system. These connections will be valid at the time that the array was created, but may be invalidated by other threads before you get to examine the array.

connectionWithReceivePort: sendPort: 

+ (NSConnection*) connectionWithReceivePort: (NSPort*)r sendPort: (NSPort*)s;
Availability: OpenStep

Returns a connection initialised using -initWithReceivePort:sendPort:
Both ports must be of the same type.

connectionWithRegisteredName: host: 

+ (NSConnection*) connectionWithRegisteredName: (NSString*)n host: (NSString*)h;
Availability: OpenStep

Returns an NSConnection object whose send port is that of the NSConnection registered under the name n on the host h

This method calls +connectionWithRegisteredName:host:usingNameServer: using the default system name server.

Use NSSocketPortNameServer for connections to remote hosts.


connectionWithRegisteredName: host: usingNameServer: 

+ (NSConnection*) connectionWithRegisteredName: (NSString*)n host: (NSString*)h usingNameServer: (NSPortNameServer*)s;
Availability: OpenStep

Returns an NSConnection object whose send port is that of the NSConnection registered under name on host.

The nameserver server is used to look up the send port to be used for the connection.
Use [NSSocketPortNameServer +sharedInstance] for connections to remote hosts.

If host is nil or an empty string, the host is taken to be the local machine.
If it is an asterisk ('*') then the nameserver checks all hosts on the local subnet (unless the nameserver is one that only manages local ports).
In the GNUstep implementation, the local host is searched before any other hosts.
NB. if the nameserver does not support connections to remote hosts (the default situation) the host argeument should be omitted.

If no NSConnection can be found for name and host host, the method returns nil.

The returned object has the default NSConnection of the current thread as its parent (it has the same receive port as the default connection).


currentConversation 

+ (id) currentConversation;
Availability: OpenStep

Return the current conversation... not implemented in GNUstep

defaultConnection 

+ (NSConnection*) defaultConnection;
Availability: OpenStep

Returns the default connection for a thread.
Creates a new instance if necessary.
The default connection has a single NSPort object used for both sending and receiving - this it can't be used to connect to a remote process, but can be used to vend objects.
Possible problem - if the connection is invalidated, it won't be cleaned up until this thread calls this method again. The connection and it's ports could hang around for a very long time.

rootProxyForConnectionWithRegisteredName: host: 

+ (NSDistantObject*) rootProxyForConnectionWithRegisteredName: (NSString*)n host: (NSString*)h;
Availability: OpenStep

This method calls +rootProxyForConnectionWithRegisteredName:host:usingNameServer: to return a proxy for a root object on the remote connection with the send port registered under name n on host h.

rootProxyForConnectionWithRegisteredName: host: usingNameServer: 

+ (NSDistantObject*) rootProxyForConnectionWithRegisteredName: (NSString*)n host: (NSString*)h usingNameServer: (NSPortNameServer*)s;
Availability: OpenStep

This method calls +connectionWithRegisteredName:host:usingNameServer: to get a connection, then sends it a -rootProxy message to get a proxy for the root object being vended by the remote connection. Returns the proxy or nil if it couldn't find a connection or if the root object for the connection has not been set.
Use [NSSocketPortNameServer +sharedInstance] for connections to remote hosts.

serviceConnectionWithName: rootObject: 

+ (id) serviceConnectionWithName: (NSString*)name rootObject: (id)root;
Availability: MacOS-X 10.5.0

Description forthcoming.

serviceConnectionWithName: rootObject: usingNameServer: 

+ (id) serviceConnectionWithName: (NSString*)name rootObject: (id)root usingNameServer: (NSPortNameServer*)server;
Availability: MacOS-X 10.5.0

Description forthcoming.

addRequestMode: 

- (void) addRequestMode: (NSString*)mode;
Availability: OpenStep

Adds mode to the run loop modes that the NSConnection will listen to for incoming messages.

addRunLoop: 

- (void) addRunLoop: (NSRunLoop*)loop;
Availability: OpenStep

Adds loop to the set of run loops that the NSConnection will listen to for incoming messages.

delegate 

- (id) delegate;
Availability: OpenStep

Returns the delegate of the NSConnection.

enableMultipleThreads 

- (void) enableMultipleThreads;
Availability: OpenStep

Sets the NSConnection configuration so that multiple threads may use the connection to send requests to the remote connection.
This option is inherited by child connections.
NB. A connection with multiple threads enabled will run slower than a normal connection.

independentConversationQueueing 

- (BOOL) independentConversationQueueing;
Availability: OpenStep

Returns YES if the NSConnection is configured to handle remote messages atomically, NO otherwise.
This option is inherited by child connections.

initWithReceivePort: sendPort: 

- (id) initWithReceivePort: (NSPort*)r sendPort: (NSPort*)s;
Availability: OpenStep

This is a designated initialiser for the class.
Initialises an NSConnection with the receive port r and the send port s.
Behavior varies with the port values as follows -
r is nil
The NSConnection is released and the method returns nil.
s is nil
The NSConnection uses r as the send port as well as the receive port.
s is the same as r
The NSConnection is usable only for vending objects.
A connection with the same ports exists
The new connection is released and the old connection is retained and returned.
A connection with the same ports (swapped) exists
The new connection is initialised as normal, and will communicate with the old connection.

If a connection exists whose send and receive ports are both the same as the new connections receive port, that existing connection is deemed to be the parent of the new connection. The new connection inherits configuration information from the parent, and the delegate of the parent has a chance to adjust the configuration of the new connection or veto its creation.
NSConnectionDidInitializeNotification is posted once a new connection is initialised.


invalidate 

- (void) invalidate;
Availability: OpenStep

Marks the receiving NSConnection as invalid.
Removes the NSConnections ports from any run loops.
Posts an NSConnectionDidDieNotification.
Invalidates all remote objects and local proxies.

isValid 

- (BOOL) isValid;
Availability: OpenStep

Returns YES if the connection is valid, NO otherwise. A connection is valid until it has been sent an -invalidate message.

localObjects 

- (NSArray*) localObjects;
Availability: OpenStep

Returns an array of all the local objects that have proxies at the remote end of the connection because they have been sent over the connection and not yet released by the far end.

multipleThreadsEnabled 

- (BOOL) multipleThreadsEnabled;
Availability: OpenStep

Returns YES if the connection permits multiple threads to use it to send requests, NO otherwise.
See the -enableMultipleThreads method.

receivePort 

- (NSPort*) receivePort;
Availability: OpenStep

Returns the NSPort object on which incoming messages are received.

registerName: 

- (BOOL) registerName: (NSString*)name;
Availability: OpenStep

Simply invokes -registerName:withNameServer: passing it the default system nameserver.

registerName: withNameServer: 

- (BOOL) registerName: (NSString*)name withNameServer: (NSPortNameServer*)svr;
Availability: OpenStep

Registers the receive port of the NSConnection as name and unregisters the previous value (if any).
Returns YES on success, NO on failure.
On failure, the connection remains registered under the previous name.
Supply nil as name to unregister the NSConnection.

remoteObjects 

- (NSArray*) remoteObjects;
Availability: OpenStep

Returns an array of proxies to all the remote objects known to the NSConnection.

removeRequestMode: 

- (void) removeRequestMode: (NSString*)mode;
Availability: OpenStep

Removes mode from the run loop modes used to receive incoming messages.

removeRunLoop: 

- (void) removeRunLoop: (NSRunLoop*)loop;
Availability: OpenStep

Removes loop from the run loops used to receive incoming messages.

replyTimeout 

- (NSTimeInterval) replyTimeout;
Availability: OpenStep

Returns the timeout interval used when waiting for a reply to a request sent on the NSConnection. This value is inherited from the parent connection or may be set using the -setReplyTimeout: method.
The default value is the maximum delay (effectively infinite).

requestModes 

- (NSArray*) requestModes;
Availability: OpenStep

Returns an array of all the run loop modes that the NSConnection uses when waiting for an incoming request.

requestTimeout 

- (NSTimeInterval) requestTimeout;
Availability: OpenStep

Returns the timeout interval used when trying to send a request on the NSConnection. This value is inherited from the parent connection or may be set using the -setRequestTimeout: method.
The default value is the maximum delay (effectively infinite).

rootObject 

- (id) rootObject;
Availability: OpenStep

Returns the object that is made available by this connection or by its parent (the object is associated with the receive port).
Returns nil if no root object has been set.

rootProxy 

- (NSDistantObject*) rootProxy;
Availability: OpenStep

Returns the proxy for the root object of the remote NSConnection.
Generally you will wish to call [NSDistantObject -setProtocolForProxy:] immediately after obtaining such a root proxy.

runInNewThread 

- (void) runInNewThread;
Availability: OpenStep

Removes the NSConnection from the current threads default run loop, then creates a new thread and runs the NSConnection in it.

sendPort 

- (NSPort*) sendPort;
Availability: OpenStep

Returns the port on which the NSConnection sends messages.

setDelegate: 

- (void) setDelegate: (id)anObj;
Availability: OpenStep

Sets the NSConnection's delegate (without retaining it).
The delegate is able to control some of the NSConnection's behavior by implementing methods in an informal protocol.

setIndependentConversationQueueing: 

- (void) setIndependentConversationQueueing: (BOOL)flag;
Availability: OpenStep

Sets whether or not the NSConnection should handle requests arriving from the remote NSConnection atomically.
By default, this is set to NO... if set to YES then any messages arriving while one message is being dealt with, will be queued.
NB. careful - use of this option can cause deadlocks.

setReplyTimeout: 

- (void) setReplyTimeout: (NSTimeInterval)to;
Availability: OpenStep

Sets the time interval that the NSConnection will wait for a reply for one of its requests before raising an NSPortTimeoutException.
NB. In GNUstep you may also get such an exception if the connection becomes invalidated while waiting for a reply to a request.

setRequestMode: 

- (void) setRequestMode: (NSString*)mode;
Availability: OpenStep

Sets the runloop mode in which requests will be sent to the remote end of the connection. Normally this is NSDefaultRunloopMode

setRequestTimeout: 

- (void) setRequestTimeout: (NSTimeInterval)to;
Availability: OpenStep

Sets the time interval that the NSConnection will wait to send one of its requests before raising an NSPortTimeoutException.

setRootObject: 

- (void) setRootObject: (id)anObj;
Availability: OpenStep

Sets the root object that is vended by the connection.

statistics 

- (NSDictionary*) statistics;
Availability: OpenStep

Returns an object containing various statistics for the NSConnection.
On GNUstep the dictionary contains -
NSConnectionRepliesReceived
The number of messages replied to by the remote NSConnection.
NSConnectionRepliesSent
The number of replies sent to the remote NSConnection.
NSConnectionRequestsReceived
The number of messages received from the remote NSConnection.
NSConnectionRequestsSent
The number of messages sent to the remote NSConnection.
NSConnectionLocalCount
The number of local objects currently vended.
NSConnectionProxyCount
The number of remote objects currently in use.

Software documentation for the NSObject(NSConnectionDelegate) informal protocol

NSObject(NSConnectionDelegate)

Declared in:
Foundation/NSConnection.h
Availability: OpenStep

This category represents an informal protocol to which NSConnection delegates may conform... These methods are not actually implemented by NSObject, so implementing these methods in your class has the effect documented.
Method summary

authenticateComponents: withData: 

- (BOOL) authenticateComponents: (NSMutableArray*)components withData: (NSData*)authenticationData;
Availability: OpenStep

This is not an NSConnection method, but is a method that may be implemented by the delegate of an NSConnection object.

If the delegate implements this method, the NSConnection will invoke the method for every message request or reply it receives from the remote NSConnection. The delegate should use the authentication data to check all the NSData objects in the components array (ignoring NSPort objects), and return YES if they are valid, NO otherwise.

If the method returns NO then an NSFailedAuthentication exception will be raised.

In GNUstep the components array is mutable, allowing you to replace the NSData objects with your own version.


authenticationDataForComponents: 

- (NSData*) authenticationDataForComponents: (NSMutableArray*)components;
Availability: OpenStep

This is not an NSConnection method, but is a method that may be implemented by the delegate of an NSConnection object.

If the delegate implements this method, the NSConnection will invoke the method for every message request to reply it sends to the remote NSConnection. The delegate should generate authentication data by examining all the NSData objects in the components array (ignoring NSPort objects), and return the authentication data that can be used by the remote NSConnection.

If the method returns nil then an NSGenericException exception will be raised.

In GNUstep the components array is mutable, allowing you to replace the NSData objects with your own version.


connection: didConnect: 

- (NSConnection*) connection: (NSConnection*)ancestorConn didConnect: (NSConnection*)newConn;
Availability: OpenStep

Description forthcoming.

connection: shouldMakeNewConnection: 

- (BOOL) connection: (NSConnection*)parent shouldMakeNewConnection: (NSConnection*)newConnection;
Availability: OpenStep

This is not an NSConnection method, but is a method that may be implemented by the delegate of an NSConnection object.

If the delegate implements this method, it will be called whenever a new NSConnection is created that has this NSConnection as its parent. The delegate may take this opportunity to adjust the configuration of the new connection and may return a boolean value to tell the parent whether the creation of the new connection is to be permitted or not.


makeNewConnection: sender: 

- (BOOL) makeNewConnection: (NSConnection*)newConnection sender: (NSConnection*)parent;
Availability: OpenStep

An old fashioned synonym for -connection:shouldMakeNewConnection: - don't use this.


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