51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
from abc import ABC, abstractmethod
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class AbstractTransaction(ABC):
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"""Represents an atomic group of operations."""
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# child classes should override this
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operations = []
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def __init__(self):
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self.finished_operations = []
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# child classes should set this to a JSON-serializable object
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# once they are finished
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self.result = None
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def finish(self, result):
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"""
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Store a result in this object so that it can be returned to the client.
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"""
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self.result = result
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@abstractmethod
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def child_execute_iter(self):
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"""
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Template Method design pattern. To be implemented by child classes.
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Every time an operation is completed, it should be yielded.
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"""
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raise NotImplementedError()
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def execute_iter(self):
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"""
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Execute the transaction, yielding an operation each time
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one is completed.
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"""
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for operation in self.child_execute_iter():
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self.finished_operations.append(operation)
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yield operation
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def execute(self):
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"""Execute the transaction synchronously."""
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for _ in self.execute_iter():
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pass
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def rollback(self):
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"""
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Roll back the transaction, when it fails.
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If the transaction only has one operation, then there is no need
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to implement this.
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"""
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pass
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