BLIP/BLIPDispatcher.h
author Jens Alfke <jens@mooseyard.com>
Sun May 10 19:00:50 2009 -0700 (2009-05-10)
changeset 45 8efb48eabd08
parent 8 6f539dd9921c
permissions -rw-r--r--
Fixed MYAddressLookup to allocate an NSSet, and to send correct KV notifications. (Based on Jim Roepke's patch, but outsourcing the KV grunge to CollectionUtils.)
     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     @private
    29     NSMutableArray *_predicates, *_targets;
    30     BLIPDispatcher *_parent;
    31 }
    32 
    33 /** The inherited parent dispatcher.
    34     If a message does not match any of this dispatcher's rules, it will next be passed to
    35     the parent, if there is one. */
    36 @property (retain) BLIPDispatcher *parent;
    37 
    38 /** Convenience method that adds a rule that compares a property against a string. */
    39 - (void) addTarget: (MYTarget*)target forValueOfProperty: (NSString*)value forKey: (NSString*)key;
    40 
    41 #if ! TARGET_OS_IPHONE      /* NSPredicate is not available on iPhone, unfortunately */
    42 /** Adds a new rule, to call a given target method if a given predicate matches the message. */
    43 - (void) addTarget: (MYTarget*)target forPredicate: (NSPredicate*)predicate;
    44 #endif
    45 
    46 /** Removes all rules with the given target method. */
    47 - (void) removeTarget: (MYTarget*)target;
    48 
    49 /** Tests the message against all the rules, in the order they were added, and calls the
    50     target of the first matching rule.
    51     If no rule matches, the message is passed to the parent dispatcher's -dispatchMessage:,
    52     if there is a parent.
    53     If no rules at all match, NO is returned. */
    54 - (BOOL) dispatchMessage: (BLIPMessage*)message;
    55 
    56 /** Returns a target object that will call this dispatcher's -dispatchMessage: method.
    57     This can be used to make this dispatcher the target of another dispatcher's rule,
    58     stringing them together hierarchically. */
    59 - (MYTarget*) asTarget;
    60 
    61 @end