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69 lines
2.8 KiB
Python
69 lines
2.8 KiB
Python
"""
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Module for implementing the conditional node
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"""
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from .base_node import BaseNode
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class ConditionalNode(BaseNode):
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"""
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A node that determines the next step in the graph's execution flow based on
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the presence and content of a specified key in the graph's state. It extends
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the BaseNode by adding condition-based logic to the execution process.
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This node type is used to implement branching logic within the graph, allowing
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for dynamic paths based on the data available in the current state.
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Attributes:
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key_name (str): The name of the key in the state to check for its presence.
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next_nodes (list): A list of two node instances. The first node is chosen
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for execution if the key exists and has a non-empty value,
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and the second node is chosen if the key does not exist or
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is empty.
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Args:
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key_name (str): The name of the key to check in the graph's state. This is
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used to determine the path the graph's execution should take.
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next_nodes (list): A list containing exactly two node instances, specifying
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the next nodes to execute based on the condition's outcome.
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node_name (str, optional): The unique identifier name for the node. Defaults
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to "ConditionalNode".
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Raises:
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ValueError: If next_nodes does not contain exactly two elements, indicating
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a misconfiguration in specifying the conditional paths.
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"""
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def __init__(self, key_name: str, next_nodes: list, node_name="ConditionalNode"):
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"""
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Initializes the node with the key to check and the next node names based on the condition.
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Args:
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key_name (str): The name of the key to check in the state.
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next_nodes (list): A list containing exactly two names of the next nodes.
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The first is used if the key exists, the second if it does not.
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Raises:
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ValueError: If next_nodes does not contain exactly two elements.
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"""
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super().__init__(node_name, "conditional_node")
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self.key_name = key_name
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if len(next_nodes) != 2:
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raise ValueError("next_nodes must contain exactly two elements.")
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self.next_nodes = next_nodes
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def execute(self, state: dict) -> str:
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"""
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Checks if the specified key is present in the state and decides the next node accordingly.
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Args:
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state (dict): The current state of the graph.
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Returns:
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str: The name of the next node to execute based on the presence of the key.
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"""
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if self.key_name in state and len(state[self.key_name]) > 0:
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return self.next_nodes[0].node_name
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return self.next_nodes[1].node_name
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