BLIP/BLIPDispatcher.h
author Jens Alfke <jens@mooseyard.com>
Fri May 30 13:54:38 2008 -0700 (2008-05-30)
changeset 9 980beba83fb7
parent 2 9fdd8dba529c
child 26 cb9cdf247239
permissions -rw-r--r--
Fixed a serious bug - a race condition where a data buffer in the writer's queue could be dealloced (not the NSData, but its bytes themselves) before the writer sent it, resulting in an EFAULT error.
     1 //
     2 //  BLIPDispatcher.h
     3 //  MYNetwork
     4 //
     5 //  Created by Jens Alfke on 5/15/08.
     6 //  Copyright 2008 Jens Alfke. All rights reserved.
     7 //
     8 
     9 #import <Foundation/Foundation.h>
    10 @class MYTarget, BLIPMessage;
    11 
    12 
    13 /** Routes BLIP messages to targets based on a series of rules.
    14  
    15     Every BLIPConnection has a BLIPDispatcher, which is initially empty, but you can add rules
    16     to it.
    17  
    18     Every BLIPListener also has a dispatcher, which is inherited as the parent by every
    19     connection that it accepts, so you can add rules to the listener's dispatcher to share them
    20     between all connections.
    21  
    22     It's not necessary to use a dispatcher. Any undispatched requests will be sent to the
    23     BLIPConnection's delegate's -connection:receivedRequest: method, which can do its own
    24     custom handling. But it's often easier to use the dispatcher to associate handlers with
    25     request based on property values. */
    26 @interface BLIPDispatcher : NSObject 
    27 {
    28     NSMutableArray *_predicates, *_targets;
    29     BLIPDispatcher *_parent;
    30 }
    31 
    32 /** The inherited parent dispatcher.
    33     If a message does not match any of this dispatcher's rules, it will next be passed to
    34     the parent, if there is one. */
    35 @property (retain) BLIPDispatcher *parent;
    36 
    37 /** Convenience method that adds a rule that compares a property against a string. */
    38 - (void) addTarget: (MYTarget*)target forValueOfProperty: (NSString*)value forKey: (NSString*)key;
    39 
    40 #if ! TARGET_OS_IPHONE      /* NSPredicate is not available on iPhone, unfortunately */
    41 /** Adds a new rule, to call a given target method if a given predicate matches the message. */
    42 - (void) addTarget: (MYTarget*)target forPredicate: (NSPredicate*)predicate;
    43 #endif
    44 
    45 /** Removes all rules with the given target method. */
    46 - (void) removeTarget: (MYTarget*)target;
    47 
    48 /** Tests the message against all the rules, in the order they were added, and calls the
    49     target of the first matching rule.
    50     If no rule matches, the message is passed to the parent dispatcher's -dispatchMessage:,
    51     if there is a parent.
    52     If no rules at all match, NO is returned. */
    53 - (BOOL) dispatchMessage: (BLIPMessage*)message;
    54 
    55 /** Returns a target object that will call this dispatcher's -dispatchMessage: method.
    56     This can be used to make this dispatcher the target of another dispatcher's rule,
    57     stringing them together hierarchically. */
    58 - (MYTarget*) asTarget;
    59 
    60 @end