Class: ClassLoader

Inherits:
AuxLoader show all
Defined in:
lib/vcseif/utils/auxloader.rb

Class Method Summary collapse

Methods inherited from AuxLoader

getFacility, is_qualified?, loadFacility

Class Method Details

.loadConnectionClass(subdir, class_name, facility_name = nil) ⇒ Object 



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# File 'lib/vcseif/utils/auxloader.rb', line 140

def self.loadConnectionClass(subdir, class_name, facility_name=nil)
    %{
        A generalized means of loading a class. 
        The priority ladder is to first attempt to find and load
        the class_name from the specific subdir named in any facility_name supplied,
        In the event that fails, the next attempt to get the class loaded in 
        looks in the '#{ENV['VCS_APP_ROOT']}/lib/vcseif' subdirectory.
        If that also fails, an attempt is made to load the class via 
        Kernel.const_get in the event that the class is in an already loaded gem.
        If a facility_name is given, it restricts the location of the class
        to a specific Ruby file (named by facility_name, which would be the part of 
        the filename without the ".rb" suffix).
     }
##
##        $stdout.write("call of ClassLoader.loadConnectionClass(#{subdir}, #{class_name}, #{facility_name})\n")
##        $stdout.flush()
##
    candidates = [[1, subdir], [2, 'lib/vcseif']]
    for rung, candidate in candidates do
        fq_facility_dir = "#{ENV['VCS_APP_ROOT']}/#{candidate}"  # fully qualified path to candidate
        if not File.exists?(fq_facility_dir) or not File.directory?(fq_facility_dir)
##
##              $stdout.write("    rung ##{rung} of loadConnectionClass skipped\n")
##
            next
        end

        success = false
        begin
            conn_class = loadFacility(candidate, class_name, facility_name)
##
##              $stdout.write("    rung ##{rung} of loadConnectionClass succeeded\n")
##              $stdout.flush()
##
            success = true
        rescue Exception => ex
##
##              $stdout.write("    rung ##{rung} of loadConnectionClass failed...\n")
##              $stdout.flush()
##
            raise if ex.message.include?("defined in more than one file")
        end
        return conn_class if success

    end

    #
    # try a Kernel.const_get(class_name) to see
    # if we can obtain the class from an already loaded relevant *eif gem
    #
    begin
        @@facility_class = Kernel.const_get(class_name)
        success = true
    rescue Exception => ex
        $stderr.write("Caught exception attempting to load #{class_name}: #{ex.message}\n")
        raise
    end
    return @@facility_class if success

    return nil
end