Difference between revisions of "Persistence code samples"
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You can download the source code here (TODO: provide a link to the sources) | You can download the source code here (TODO: provide a link to the sources) | ||
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+ | You can also go back to the [[persistence unified]] page. | ||
==Simplified BON diagram== | ==Simplified BON diagram== | ||
==PERSISTENCE_MANAGER== | ==PERSISTENCE_MANAGER== |
Revision as of 01:49, 19 August 2007
Here the main classes of the framework are sketched.
For an open discussion on the design choices have a look at the persistence framework design discussion.
You can download the source code here (TODO: provide a link to the sources)
You can also go back to the persistence unified page.
Contents
Simplified BON diagram
PERSISTENCE_MANAGER
class PERSISTENCE_MANAGER feature -- Access medium: PERSISTENCE_MEDIUM -- the chosen medium format: PERSISTENCE_FORMAT -- the chosen format feature -- Basic operations store (an_object:ANY) -- persists an_object using the format and medium stored by current object require an_object_exists:an_object /= Void medium_exists: medium /= Void do format.store(an_object,medium) end retrieve: ANY -- retrieves an_object using the medium and format stored by current object require medium_exists: medium /= Void do Result:=format.retrieve(medium) end end
BINARY_SERIALIZATION_MANAGER
class BINARY_SERIALIZATION_MANAGER inherit PERSISTENCE_MANAGER create make feature -- Creation make (file_name: STRING) -- Creation procedure require file_name_exists: file_name /= Void do create {FILE_MEDIUM} medium.make (file_name) create {INDEPENDENT_BINARY_FORMAT} format ensure medium_exists: medium /= Void format_exists: format /= Void end end
PERSISTENCE_FORMAT
deferred class PERSISTENCE_FORMAT feature -- Basic operations store (object:ANY; medium:PERSISTENCE_MEDIUM) -- stores object using medium require object_exists: object /= Void medium_exists: medium /= Void deferred end retrieve (medium: PERSISTENCE_MEDIUM):ANY require medium_exists: medium /= Void deferred end end
BINARY_FORMAT
deferred class BINARY_FORMAT inherit PERSISTENCE_FORMAT redefine store, retrieve end feature -- Access store_handler:SED_STORABLE_FACILITIES serializer:SED_MEDIUM_READER_WRITER feature -- Basic operations store (object:ANY; data_file:FILE_MEDIUM) -- stores object using a FILE_MEDIUM do create store_handler create serializer.make (data_file.raw_file) if data_file.exists then data_file.reopen_write (data_file.file_name) else data_file.open_write end serializer.set_for_writing store_now (object) end store_now (object_to_store:ANY) --proper store operation depends on specific descendant require object_to_store_exists:object_to_store/=Void deferred end retrieve (data_file:FILE_MEDIUM):ANY -- retrieves object using a FILE_MEDIUM do create store_handler create serializer.make (data_file.raw_file) if data_file.exists then data_file.open_read serializer.set_for_reading Result:= store_handler.retrieved (serializer,true) else print ("%NData file does not exist! ") end end end
INDEPENDENT_BINARY_FORMAT
class INDEPENDENT_BINARY_FORMAT inherit BINARY_FORMAT feature -- Access optimized_for_retrieval: BOOLEAN feature -- Status setting set_optimized_for_retrieval (is_optimized_for_retrieval:BOOLEAN) do optimized_for_retrieval:= is_optimized_for_retrieval ensure optimized_for_retrieval_set:optimized_for_retrieval = is_optimized_for_retrieval end feature -- Basic operations store_now (object_to_store:ANY) do store_handler.independent_store(object_to_store,serializer,optimized_for_retrieval) end end
FILE_MEDIUM
class FILE_MEDIUM inherit PERSISTENCE_MEDIUM create make feature --Creation make (a_file_name:STRING) require a_file_name_exists:a_file_name /= Void do create raw_file.make (a_file_name) file_name:=a_file_name ensure raw_file_exists: raw_file /=Void file_name_set: file_name = a_file_name end feature -- Access raw_file: RAW_FILE file_name: STRING feature -- Status report exists: BOOLEAN do Result:= raw_file.exists end feature -- Basic operations reopen_write (a_file_name:STRING) -- reopens the file named 'a_file_name' for writing require a_file_name_exists:a_file_name /= Void do raw_file.reopen_write (a_file_name) end open_write -- opens the current file for writing require a_file_to_open_exists:raw_file /= Void do raw_file.open_write end open_read -- opens the current file for reading do raw_file.open_read end end