mirror of
https://github.com/rjNemo/design-patterns
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459ddde228
* doc: create documentation * chore: put package in the right place * doc: edit general doc * add code example
38 lines
1.1 KiB
Python
38 lines
1.1 KiB
Python
from typing import Optional
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from behavioral.command.command import Command
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class Invoker:
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"""
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The Invoker is associated with one or several commands. It sends a request
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to the command.
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"""
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_on_start: Optional[Command] = None
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_on_finish: Optional[Command] = None
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"""Initialize commands."""
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def set_on_start(self, command: Command) -> None:
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self._on_start = command
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def set_on_finish(self, command: Command) -> None:
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self._on_finish = command
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def do_something_important(self) -> None:
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"""
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The Invoker does not depend on concrete command or receiver classes. The
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Invoker passes a request to a receiver indirectly, by executing a
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command.
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"""
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print("Invoker: Does anybody want something done before I begin?")
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if self._on_start:
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self._on_start.execute()
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print("Invoker: ...doing something really important...")
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print("Invoker: Does anybody want something done after I finish?")
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if self._on_finish:
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self._on_finish.execute()
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