Class | Jabber::CallbackList |
In: |
lib/xmpp4r/callbacks.rb
|
Parent: | Object |
This class manages a list of callbacks.
Callbacks are managed by the class CallbackList. When they are added, a priority (just a number or anything Comparable with other priorities) is specified. The biggest the priority is, the earliest the callback will be considered.
Callbacks are processed for a given set of objects as long as they return false. If you want to stop processing, you must return true. Example :
cbl = CallbackList.new c1 = false c2 = false c3 = false cbl.add(10) { c1 = true; 1 } cbl.add(5) { c2 = true; true } cbl.add(0) { c3 = true } cbl.process('aa') puts "#{c1} #{c2} #{c3}"
This example would display "true true false" as callbacks processing was stopped after the second callback returned true.
In XMPP4R, callbacks’ priorities are quite normalized since we want to be able to "cascade" callbacks in a clean way. Here are values your code should take into account :
>= 200: | logging & debugging callbacks. Those callbacks should not consume elements. |
100-199: | Where Helpers register their callbacks. The normal value is 100, and Helpers shouldn‘t register something else unless there‘s a very good reason to. |
< 100: | all those numbers are normally available for your application. That‘s enough, don‘t you think ? |
Add a callback to the list
List will be sorted afterwards
prio: | [Integer] the callback‘s priority, the higher, the sooner. |
ref: | [String] the callback‘s reference |
block: | [Block] a block to execute |
return: | [Jabber::CallbackList] The list, for chaining |
# File lib/xmpp4r/callbacks.rb, line 57 57: def add(prio = 0, ref = nil, proc = nil, &block) 58: block = proc if proc 59: @list.push(Callback.new(prio, ref, block)) 60: @list.sort! { |a, b| b.priority <=> a.priority } 61: self 62: end
Number of elements in the list
return: | [Integer] The number of elements |
# File lib/xmpp4r/callbacks.rb, line 76 76: def length 77: @list.length 78: end
Process an element through all my callbacks. returns e.consumed?
e: | [Object] The elements to pass to the callback. You can pass |
several, but of course, you block must know how to handle them.
return: | [Boolean] true if the element has been consumed |
# File lib/xmpp4r/callbacks.rb, line 85 85: def process(*e) 86: # If somebody adds a new callback the list will get modified 87: # and sorted(!) while still iterating through it. So we use a 88: # local copy of @list. Any freshly added callback will receive 89: # the next stanzas, not the current. 90: list = @list.dup 91: 92: # process through callbacks 93: list.each do |item| 94: return true if item.block.call(*e) == true 95: end 96: false 97: end