NAME

DS::Importer - component that retrieves data from outside DS and passes it down a processing chain.

DESCRIPTION

This is the base class of any component that is supposed to retrieve data from outside a processing chain and pass it on as rows. The name refers to a component that imports data into a chain.

SUPER CLASSES

DS::Source

METHODS

execute( $num_rows )

Will call fetch pass the results on by calling pass_row with the result, stopping after fetching $num_rows or passing on end of stream (whichever comes first).

fetch

This method is supposed to retrieve a row from the underlying data source and return it. Must return undef to indicate end of stream. Multiple calls after end of stream should still result in returning undef.

new( $class, $out_type, $target )

Constructor. Instantiates an object of class $class, returning the type $out_type, attaced to the target $target. Besides $class, any of the parameters can be left out.

INHERITED METHODS

Methods inherited from DS::Source:

attach_target( $target )

target( $target )

pass_row( $row )

out_type( $type )

SEE ALSO

DS::Importer, DS::Transformer, DS::Target.

AUTHOR

Written by Michael Zedeler.