19.1.95. camcops_server.tasks.hads


Copyright (C) 2012-2018 Rudolf Cardinal (rudolf@pobox.com).

This file is part of CamCOPS.

CamCOPS is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

CamCOPS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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class camcops_server.tasks.hads.Hads(**kwargs)[source]
class camcops_server.tasks.hads.HadsBase(**kwargs)[source]
get_clinical_text(req: camcops_server.cc_modules.cc_request.CamcopsRequest) → List[camcops_server.cc_modules.cc_ctvinfo.CtvInfo][source]

Tasks that provide clinical text information should override this to provide a list of dictionaries.

Return None (default) for a task that doesn’t provide clinical text, or [] for one with no information, or a list of CtvInfo objects.

get_summaries(req: camcops_server.cc_modules.cc_request.CamcopsRequest) → List[camcops_server.cc_modules.cc_summaryelement.SummaryElement][source]

Return a list of summary value objects, for this database object (not any dependent classes/tables).

get_task_html(req: camcops_server.cc_modules.cc_request.CamcopsRequest) → str[source]

HTML for the main task content. Overridden by derived classes.

get_trackers(req: camcops_server.cc_modules.cc_request.CamcopsRequest) → List[camcops_server.cc_modules.cc_trackerhelpers.TrackerInfo][source]

Tasks that provide quantitative information for tracking over time should override this and return a list of TrackerInfo, one per tracker.

The information is read by get_all_plots_for_one_task_html() in cc_tracker.py – q.v.

Time information will be retrieved using the get_creation_datetime() function.

is_complete() → bool[source]

Is the task instance complete? Must be overridden.

class camcops_server.tasks.hads.HadsMetaclass(name: str, bases: Tuple[Type, ...], classdict: Dict[str, Any])[source]

We can’t make this metaclass inherit from DeclarativeMeta.

This works:

… but at the point that MyTaskMetaclass calls DeclarativeMeta.__init__, it registers “cls” (in this case MyTask) with the SQLAlchemy class registry. In this example, that’s fine, because MyTask wants to be registered. But here it fails:

… and it fails because OtherTaskMetaclass calls DeclarativeMeta.__init__ and this tries to register “Intermediate” with the SQLALchemy ORM.

So, it’s clear that OtherTaskMetaclass shouldn’t derive from DeclarativeMeta. But if we make it derive from “object” instead, we get the error

because OtherTask inherits from Base, whose metaclass is DeclarativeMeta, but there is another metaclass in the metaclass set that is incompatible with this.

So, is solution that OtherTaskMetaclass should derive from “type” and then to use CooperativeMeta (q.v.) for OtherTask?

No, that still seems to fail (and before any CooperativeMeta code is called) – possibly that framework is for Python 2 only.

See also https://blog.ionelmc.ro/2015/02/09/understanding-python-metaclasses/

Alternative solution 1: make a new metaclass that pretends to inherit from HadsMetaclass and DeclarativeMeta.

WENT WITH THIS ONE INITIALLY:

Alternative solution 2: continue to have the HadsMetaclass deriving from DeclarativeMeta, but add it in at the last stage.

IGNORE THIS, NO LONGER TRUE:

  • ALL THIS SOMEWHAT REVISED to handle SQLAlchemy concrete inheritance (q.v.), with the rule that “the only things that inherit from Task are actual tasks”; Task then inherits from both AbstractConcreteBase and Base.

SEE ALSO sqla_database_structure.txt

FINAL ANSWER:

  • classes inherit in a neat chain from Base -> [+/- Task -> …]
  • metaclasses inherit in a neat chain from DeclarativeMeta
  • abstract intermediates mark themselves with “__abstract__ = True”

Yes, that’s it. (Note that if you erroneously also add “metaclass=HadsMetaclass” on Hads, you get: “TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases.”)

class camcops_server.tasks.hads.HadsRespondent(**kwargs)[source]