microsoft--graphrag/packages/graphrag-common/example_notebooks/factory_module_example.ipynb

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    "# Copyright (c) 2026 Microsoft Corporation.\n",
    "# Licensed under the MIT License."
   ]
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    "## Factory module example\n",
    "\n",
    "The Factory class provides a flexible dependency injection pattern that can register and create instances of classes implementing a common interface using string-based strategies. It supports both transient scope (creates new instances on each request) and singleton scope (returns the same instance after first creation)."
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    "from abc import ABC, abstractmethod\n",
    "\n",
    "from graphrag_common.factory import Factory\n",
    "\n",
    "\n",
    "class SampleABC(ABC):\n",
    "    \"\"\"Abstract base class for sample implementations.\"\"\"\n",
    "\n",
    "    @abstractmethod\n",
    "    def get_value(self) -> str:\n",
    "        \"\"\"Return the value of the sample implementation.\"\"\"\n",
    "        msg = \"Subclasses must implement the get_value method.\"\n",
    "        raise NotImplementedError(msg)\n",
    "\n",
    "\n",
    "class ConcreteClass(SampleABC):\n",
    "    \"\"\"A concrete implementation of SampleABC.\"\"\"\n",
    "\n",
    "    def __init__(self, value: str):\n",
    "        print(f\"Creating ConcreteClass with value: {value}\")\n",
    "        self._value = value\n",
    "\n",
    "    def get_value(self) -> str:\n",
    "        \"\"\"Return the value of the sample implementation.\"\"\"\n",
    "        return self._value\n",
    "\n",
    "\n",
    "class SampleFactory(Factory[SampleABC]):\n",
    "    \"\"\"A Factory for SampleABC classes.\"\"\"\n",
    "\n",
    "\n",
    "factory = SampleFactory()"
   ]
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     "text": [
      "Creating ConcreteClass with value: test1\n",
      "Creating ConcreteClass with value: test2\n",
      "Value from trans1: test1\n",
      "Value from trans2: test2\n"
     ]
    }
   ],
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    "# Registering transient services\n",
    "# A new one is created for every request\n",
    "factory.register(\"some_strategy\", ConcreteClass)\n",
    "\n",
    "trans1 = factory.create(\"some_strategy\", {\"value\": \"test1\"})\n",
    "trans2 = factory.create(\"some_strategy\", {\"value\": \"test2\"})\n",
    "\n",
    "print(f\"Value from trans1: {trans1.get_value()}\")  # Output: test1\n",
    "print(f\"Value from trans2: {trans2.get_value()}\")  # Output: test2\n",
    "\n",
    "assert trans1 is not trans2\n",
    "assert trans1.get_value() == \"test1\"\n",
    "assert trans2.get_value() == \"test2\""
   ]
  },
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   "cell_type": "code",
   "execution_count": 31,
   "id": "45e9ed13",
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     "text": [
      "Creating ConcreteClass with value: singleton\n",
      "Creating ConcreteClass with value: ignored\n",
      "Value from single1: singleton\n",
      "Value from single2: ignored\n"
     ]
    }
   ],
   "source": [
    "# Registering singleton services\n",
    "# After first creation, the same one is returned every time\n",
    "factory.register(\"some_other_strategy\", ConcreteClass, scope=\"singleton\")\n",
    "\n",
    "single1 = factory.create(\"some_other_strategy\", {\"value\": \"singleton\"})\n",
    "single2 = factory.create(\"some_other_strategy\", {\"value\": \"ignored\"})\n",
    "\n",
    "print(f\"Value from single1: {single1.get_value()}\")  # Output: singleton\n",
    "print(f\"Value from single2: {single2.get_value()}\")  # Output: singleton\n",
    "\n",
    "assert single1 is not single2\n",
    "assert single1.get_value() == \"singleton\"\n",
    "assert single2.get_value() == \"ignored\""
   ]
  }
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