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require 'English'
#
# Handler Chain
#
# A chain of handlers that respond to call. Invoking handle(*args) on the chain
# will call the handlers with the given args until one of them returns a result
# that is truethy (i.e. not false or nil).
#
# You can specify exception classes to rescue with
# handler_chain.continue_on ErrorClass1, ErrorClass2
# These exceptions will be rescued and tracked. The chain will proceed even if
# one handler raised the given exception. Afterwards you can inspect them with
# handler_chain.rescued_exceptions
#
module Nickserver
class HandlerChain
def initialize(*handlers)
@handlers = handlers
@exceptions_to_rescue = []
@rescued_exceptions = []
end
def continue_on(*exceptions)
self.exceptions_to_rescue += exceptions
end
def handle(*args)
result = nil
_handled_by = @handlers.find { |h| result = try_handler(h, *args) }
result
end
attr_reader :rescued_exceptions
protected
attr_writer :rescued_exceptions
attr_accessor :exceptions_to_rescue
def try_handler(handler, *args)
result = handler.call(*args)
rescue *exceptions_to_rescue
rescued_exceptions << $ERROR_INFO
result = false
end
end
end
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