/lib/chingu/async/task_builder.rb

 1#--
 2#
 3# Chingu -- OpenGL accelerated 2D game framework for Ruby
 4# Copyright (C) 2009 ippa / ippa@rubylicio.us
 5#
 6# This library is free software; you can redistribute it and/or
 7# modify it under the terms of the GNU Lesser General Public
 8# License as published by the Free Software Foundation; either
 9# version 2.1 of the License, or (at your option) any later version.
10#
11# This library is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14# Lesser General Public License for more details.
15#
16# You should have received a copy of the GNU Lesser General Public
17# License along with this library; if not, write to the Free Software
18# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19#
20#++
21
22module Chingu
23  module Async
24    
25    #
26    # Implements a DSL for appending new tasks to an task queue.
27    #
28    class TaskBuilder
29      def initialize(tasks)
30        @tasks = tasks
31      end
32      
33      #
34      # Add a new task to the queue. The first argument is a Symbol or
35      # String naming the type of task; remaining arguments are passed
36      # on to the task's constructor.
37      # 
38      # If a block is supplied, it is scheduled to be executed as soon as the
39      # task is finished.
40      #
41      def task(task, *args, &block)
42        case task
43        when Symbol, String
44          klass_name = Chingu::Inflector.camelize(task)
45          klass = Chingu::AsyncTasks.const_get(klass_name)
46          
47          task = klass.new(*args, &block)
48          
49        when Chingu::Async::BasicTask
50          # pass
51          
52        when Class
53          task = task.new(*args, &block)
54          
55        else raise TypeError, "task must be a Task object or task name"
56        end
57        
58        @tasks.enq(task)
59        task
60      end
61      
62      #
63      # Attempting to invoke a nonexistant method automatically calls
64      # +task+ with the method name as the task type.
65      #
66      alias :method_missing :task
67      
68    end
69    
70  end
71end