#
# Copyright (c) 2006 The Apache Software Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require "thread"

module Qpid

  class Closed < Exception; end

  class Queue < Queue

    @@END = Object.new()

    def close()
      # sentinal to indicate the end of the queue
      self << @@END
    end

    def pop(*args)
      result = super(*args)
      if @@END.equal? result
        # we put another sentinal on the end in case there are
        # subsequent calls to pop by this or other threads
        self << @@END
        raise Closed.new()
      else
        return result
      end
    end

    alias shift pop
    alias deq pop

  end

end
