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"""Concurrency concepts that support efficient multi-threading."""

from concurrent.futures import Executor, ThreadPoolExecutor
from typing import Optional

from pyiceberg.utils.config import Config


class ExecutorFactory:
    _instance: Optional[Executor] = None

    @staticmethod
    def get_or_create() -> Executor:
        """Return the same executor in each call."""
        if ExecutorFactory._instance is None:
            max_workers = ExecutorFactory.max_workers()
            ExecutorFactory._instance = ThreadPoolExecutor(max_workers=max_workers)

        return ExecutorFactory._instance

    @staticmethod
    def max_workers() -> Optional[int]:
        """Return the max number of workers configured."""
        return Config().get_int("max-workers")