Difference between revisions of "Persistence code samples"
(→BINARY_SERIALIZATION_MANAGER) |
m (apply void-safety and style guide) |
||
(29 intermediate revisions by 3 users not shown) | |||
Line 1: | Line 1: | ||
− | + | [[Category:Persistence]] | |
+ | Below are sketches of essential classes of the PERSIST framework. | ||
+ | |||
+ | For an open discussion on the design choices please 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 download the source code here (TODO: provide a link to the sources) | ||
+ | |||
+ | An example of an actually implemented library built according to the PERSIST framework is [http://dadle.origo.ethz.ch/wiki/documentation_of_the_library dadle]. | ||
+ | |||
+ | You can also go back to the [[persistence unified]] page. | ||
==Simplified BON diagram== | ==Simplified BON diagram== | ||
+ | |||
+ | [[Image:Abel_class_diagram.png]] | ||
+ | |||
==PERSISTENCE_MANAGER== | ==PERSISTENCE_MANAGER== | ||
− | < | + | <e> |
class | class | ||
PERSISTENCE_MANAGER | PERSISTENCE_MANAGER | ||
Line 10: | Line 20: | ||
feature -- Access | feature -- Access | ||
− | medium: PERSISTENCE_MEDIUM -- | + | medium: PERSISTENCE_MEDIUM |
+ | -- Chosen medium | ||
− | format: PERSISTENCE_FORMAT -- | + | format: PERSISTENCE_FORMAT |
+ | -- Chosen format | ||
feature -- Basic operations | feature -- Basic operations | ||
− | store (an_object:ANY) | + | store (an_object: ANY) |
− | -- | + | -- Persists an_object using the format and medium stored by current object. |
− | + | ||
− | + | ||
− | + | ||
do | do | ||
− | format.store(an_object,medium) | + | format.store (an_object, medium) |
end | end | ||
− | retrieve:ANY | + | retrieve: ANY |
− | -- | + | -- Retrieves an_object using the medium and format stored by current object. |
− | + | ||
− | + | ||
do | do | ||
− | Result:=format.retrieve(medium) | + | Result := format.retrieve (medium) |
end | end | ||
+ | |||
end | end | ||
− | </ | + | </e> |
− | == | + | ==BINARY_PERSISTENCE_MANAGER== |
− | < | + | <e> |
class | class | ||
− | + | BINARY_PERSISTENCE_MANAGER | |
inherit | inherit | ||
Line 46: | Line 54: | ||
make | make | ||
− | feature -- | + | feature -- Initialization |
make (file_name: STRING) | make (file_name: STRING) | ||
− | -- | + | -- Initialization procedure |
− | + | ||
− | + | ||
do | do | ||
create {FILE_MEDIUM} medium.make (file_name) | create {FILE_MEDIUM} medium.make (file_name) | ||
create {INDEPENDENT_BINARY_FORMAT} format | create {INDEPENDENT_BINARY_FORMAT} format | ||
− | |||
− | |||
− | |||
end | end | ||
end | end | ||
− | </ | + | </e> |
==PERSISTENCE_FORMAT== | ==PERSISTENCE_FORMAT== | ||
+ | <e> | ||
+ | deferred class | ||
+ | PERSISTENCE_FORMAT | ||
+ | |||
+ | feature -- Basic operations | ||
+ | |||
+ | serialized_form: SERIALIZED_FORM | ||
+ | -- Desired serialized form. If exists, this is what will be serialized. | ||
+ | |||
+ | set_serialized_form (custom_serialized: SERIALIZED_FORM) | ||
+ | -- Set desired custom serialized form. This is what will be serialized. | ||
+ | do | ||
+ | serialized_form := custom_serialized | ||
+ | ensure | ||
+ | object_effect: custom_ser = serialized_form | ||
+ | end | ||
+ | |||
+ | store (object: ANY; medium: PERSISTENCE_MEDIUM) | ||
+ | -- Store 'object' using medium | ||
+ | deferred | ||
+ | end | ||
+ | |||
+ | retrieve (medium: PERSISTENCE_MEDIUM):ANY | ||
+ | deferred | ||
+ | end | ||
+ | end | ||
+ | </e> | ||
+ | |||
==BINARY_FORMAT== | ==BINARY_FORMAT== | ||
+ | |||
+ | <e> | ||
+ | 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. | ||
+ | deferred | ||
+ | end | ||
+ | |||
+ | retrieve (data_file: FILE_MEDIUM): ANY | ||
+ | -- Retrieve 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 | ||
+ | </e> | ||
+ | |||
==INDEPENDENT_BINARY_FORMAT== | ==INDEPENDENT_BINARY_FORMAT== | ||
− | < | + | <e> |
class | class | ||
INDEPENDENT_BINARY_FORMAT | INDEPENDENT_BINARY_FORMAT | ||
Line 75: | Line 162: | ||
feature -- Access | feature -- Access | ||
− | optimized_for_retrieval:BOOLEAN | + | optimized_for_retrieval: BOOLEAN |
feature -- Status setting | feature -- Status setting | ||
− | set_optimized_for_retrieval(is_optimized_for_retrieval:BOOLEAN) | + | set_optimized_for_retrieval (is_optimized_for_retrieval:BOOLEAN) |
− | + | do | |
− | + | optimized_for_retrieval:= is_optimized_for_retrieval | |
− | + | ensure | |
− | + | optimized_for_retrieval_effect: optimized_for_retrieval = is_optimized_for_retrieval | |
− | + | end | |
feature -- Basic operations | feature -- Basic operations | ||
− | store_now(object_to_store:ANY) | + | store_now (object_to_store:ANY) |
− | + | do | |
− | + | store_handler.independent_store(object_to_store,serializer,optimized_for_retrieval) | |
− | + | end | |
end | end | ||
− | </ | + | </e> |
− | |||
==FILE_MEDIUM== | ==FILE_MEDIUM== | ||
+ | <e> | ||
+ | class | ||
+ | FILE_MEDIUM | ||
+ | |||
+ | inherit | ||
+ | PERSISTENCE_MEDIUM | ||
+ | |||
+ | create | ||
+ | make | ||
+ | |||
+ | feature -- Initialization | ||
+ | |||
+ | make (a_file_name:STRING) | ||
+ | do | ||
+ | create raw_file.make (a_file_name) | ||
+ | file_name:=a_file_name | ||
+ | ensure | ||
+ | file_name_effect: 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. | ||
+ | do | ||
+ | raw_file.reopen_write (a_file_name) | ||
+ | end | ||
+ | |||
+ | open_write | ||
+ | -- Open the current file for writing. | ||
+ | do | ||
+ | raw_file.open_write | ||
+ | end | ||
+ | |||
+ | open_read | ||
+ | -- Open the current file for reading. | ||
+ | do | ||
+ | raw_file.open_read | ||
+ | end | ||
+ | |||
+ | end | ||
+ | </e> |
Latest revision as of 07:11, 20 May 2013
Below are sketches of essential classes of the PERSIST framework.
For an open discussion on the design choices please have a look at the persistence framework design discussion.
You can download the source code here (TODO: provide a link to the sources)
An example of an actually implemented library built according to the PERSIST framework is dadle.
You can also go back to the persistence unified page.
Contents
Simplified BON diagram
PERSISTENCE_MANAGER
class PERSISTENCE_MANAGER feature -- Access medium: PERSISTENCE_MEDIUM -- Chosen medium format: PERSISTENCE_FORMAT -- Chosen format feature -- Basic operations store (an_object: ANY) -- Persists an_object using the format and medium stored by current object. do format.store (an_object, medium) end retrieve: ANY -- Retrieves an_object using the medium and format stored by current object. do Result := format.retrieve (medium) end end
BINARY_PERSISTENCE_MANAGER
class BINARY_PERSISTENCE_MANAGER inherit PERSISTENCE_MANAGER create make feature -- Initialization make (file_name: STRING) -- Initialization procedure do create {FILE_MEDIUM} medium.make (file_name) create {INDEPENDENT_BINARY_FORMAT} format end end
PERSISTENCE_FORMAT
deferred class PERSISTENCE_FORMAT feature -- Basic operations serialized_form: SERIALIZED_FORM -- Desired serialized form. If exists, this is what will be serialized. set_serialized_form (custom_serialized: SERIALIZED_FORM) -- Set desired custom serialized form. This is what will be serialized. do serialized_form := custom_serialized ensure object_effect: custom_ser = serialized_form end store (object: ANY; medium: PERSISTENCE_MEDIUM) -- Store 'object' using medium deferred end retrieve (medium: PERSISTENCE_MEDIUM):ANY 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. deferred end retrieve (data_file: FILE_MEDIUM): ANY -- Retrieve 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_effect: 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 -- Initialization make (a_file_name:STRING) do create raw_file.make (a_file_name) file_name:=a_file_name ensure file_name_effect: 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. do raw_file.reopen_write (a_file_name) end open_write -- Open the current file for writing. do raw_file.open_write end open_read -- Open the current file for reading. do raw_file.open_read end end