Synnefo

# Copyright 2013 GRNET S.A. All rights reserved.

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#      disclaimer.

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#   2. Redistributions in binary form must reproduce the above

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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

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from astakos.quotaholder.exception import (

    NoCapacityError, NoStockError,

    NonImportedError, NoStockReleaseError, NonExportedError)

class Operation(object):

    @staticmethod

    def assertions(holding):

        assert(0 <= holding.imported_min)

        assert(holding.imported_min <= holding.imported_max)

        assert(0 <= holding.stock_min)

        assert(holding.stock_min <= holding.stock_max)

    @classmethod

    def _prepare(cls, holding, quantity, check=True):

        raise NotImplementedError

    @classmethod

    def prepare(cls, holding, quantity, check=True):

        cls.assertions(holding)

        cls._prepare(holding, quantity, check=True)

    @classmethod

    def _finalize(cls, holding, quantity):

        raise NotImplementedError

    @classmethod

    def finalize(cls, holding, quantity):

        cls.assertions(holding)

        cls._finalize(holding, quantity)

    @classmethod

    def undo(cls, holding, quantity):

        cls.prepare(holding, -quantity, check=False)

    @classmethod

    def revert(cls, holding, quantity):

        # Assertions do not hold when reverting

        cls._prepare(holding, -quantity, check=False)

class Import(Operation):

    @classmethod

    def _prepare(cls, holding, quantity, check=True):

        imported_max = holding.imported_max

        new_imported_max = imported_max + quantity

        capacity = holding.capacity

        if check and new_imported_max > capacity:

            holder = holding.holder

            resource = holding.resource

            m = ("%s has not enough capacity of %s." % (holder, resource))

            raise NoCapacityError(m,

                                  holder=holder,

                                  resource=resource,

                                  requested=quantity,

                                  current=imported_max,

                                  limit=capacity)

        holding.imported_max = new_imported_max

        holding.save()

    @classmethod

    def _finalize(cls, holding, quantity):

        holding.imported_min += quantity

        holding.stock_min += quantity

        holding.stock_max += quantity

        holding.save()

class Export(Operation):

    @classmethod

    def _prepare(cls, holding, quantity, check=True):

        stock_min = holding.stock_min

        new_stock_min = stock_min - quantity

        if check and new_stock_min < 0:

            holder = holding.holder

            resource = holding.resource

            m = ("%s has not enough stock of %s." % (holder, resource))

            raise NoStockError(m,

                               holder=holder,

                               resource=resource,

                               requested=quantity,

                               limit=stock_min)

        holding.stock_min = new_stock_min

        holding.save()

    @classmethod

    def _finalize(cls, holding, quantity):

        holding.stock_max -= quantity

        holding.save()

class Release(Operation):

    @classmethod

    def _prepare(cls, holding, quantity, check=True):

        imported_min = holding.imported_min

        new_imported_min = imported_min - quantity

        stock_min = holding.stock_min

        new_stock_min = stock_min - quantity

        stock_max = holding.stock_max

        new_stock_max = stock_max - quantity

        if check and new_imported_min < 0:

            holder = holding.holder

            resource = holding.resource

            m = ("%s attempts to release more %s than it contains." %

                 (holder, resource))

            raise NonImportedError(m,

                                   holder=holder,

                                   resource=resource,

                                   requested=quantity,

                                   limit=imported_min)

        if check and new_stock_min < 0:

            holder = holding.holder

            resource = holding.resource

            m = ("%s attempts to release %s that has been reexported." %

                 (holder, resource))

            raise NoStockReleaseError(m,

                                      holder=holder,

                                      resource=resource,

                                      requested=quantity,

                                      limit=stock_min)

        holding.imported_min = new_imported_min

        holding.stock_min = new_stock_min

        holding.stock_max = new_stock_max

        holding.save()

    @classmethod

    def _finalize(cls, holding, quantity):

        holding.imported_max -= quantity

        holding.save()

class Reclaim(Operation):

    @classmethod

    def _prepare(cls, holding, quantity, check=True):

        stock_max = holding.stock_max

        new_stock_max = stock_max + quantity

        imported_min = holding.imported_min

        if check and new_stock_max > imported_min:

            holder = holding.holder

            resource = holding.resource

            m = ("%s attempts to reclaim %s not originating by itself." %

                 (holder, resource))

            raise NonExportedError(m,

                                   holder=holder,

                                   resource=resource,

                                   requested=quantity,

                                   current=stock_max,

                                   limit=imported_min)

        holding.stock_max = new_stock_max

        holding.save()

    @classmethod

    def _finalize(cls, holding, quantity):

        holding.stock_min += quantity

        holding.save()

class Operations(object):

    def __init__(self):

        self.operations = []

    def prepare(self, operation, holding, quantity):

        operation.prepare(holding, quantity)

        self.operations.append((operation, holding, quantity))

    def finalize(self, operation, holding, quantity):

        operation.finalize(holding, quantity)

        self.operations.append((operation, holding, quantity))

    def undo(self, operation, holding, quantity):

        operation.undo(holding, quantity)

        self.operations.append((operation, holding, quantity))

    def revert(self):

        for (operation, holding, quantity) in self.operations:

            operation.revert(holding, quantity)