156 lines
4.7 KiB
Python
156 lines
4.7 KiB
Python
"""
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图算法服务
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提供图的最短路径等算法服务
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"""
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from typing import List, Optional, Tuple
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from models.mapping_graph import MappingGraph, GraphEdge
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from utils.graph_algorithms import GraphAlgorithms
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from utils.logger import get_logger
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logger = get_logger(__name__)
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class GraphService:
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"""图算法服务类"""
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def __init__(self):
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self.algorithms = GraphAlgorithms()
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def find_shortest_path(self, graph: MappingGraph,
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source_id: int,
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target_id: int,
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use_weight: bool = True) -> Optional[Tuple[List[int], float]]:
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"""
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查找最短路径
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Args:
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graph: 映射图
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source_id: 源节点ID
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target_id: 目标节点ID
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use_weight: 是否使用权重（True使用Dijkstra，False使用BFS）
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Returns:
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(路径节点ID列表, 总权重) 或 None
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"""
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try:
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if use_weight:
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result = self.algorithms.dijkstra_shortest_path(graph, source_id, target_id)
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if result:
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path, weight = result
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logger.info(f"Found shortest path (Dijkstra): {path}, weight: {weight}")
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return path, weight
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else:
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path = self.algorithms.bfs_shortest_path(graph, source_id, target_id)
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if path:
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logger.info(f"Found shortest path (BFS): {path}")
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return path, 0.0
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return None
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except Exception as e:
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logger.error(f"Failed to find shortest path: {e}")
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return None
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def find_all_paths(self, graph: MappingGraph,
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source_id: int,
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target_id: int,
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max_length: int = 10) -> List[List[int]]:
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"""
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查找所有路径
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Args:
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graph: 映射图
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source_id: 源节点ID
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target_id: 目标节点ID
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max_length: 最大路径长度
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Returns:
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所有路径列表
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"""
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try:
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paths = self.algorithms.find_all_paths(graph, source_id, target_id, max_length)
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logger.info(f"Found {len(paths)} paths from {source_id} to {target_id}")
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return paths
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except Exception as e:
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logger.error(f"Failed to find all paths: {e}")
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return []
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def get_path_mappings(self, graph: MappingGraph,
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path: List[int]) -> List[GraphEdge]:
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"""
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获取路径上的所有映射关系
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Args:
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graph: 映射图
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path: 路径节点ID列表
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Returns:
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边（映射关系）列表
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"""
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try:
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edges = self.algorithms.get_path_edges(graph, path)
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logger.info(f"Got {len(edges)} mappings for path")
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return edges
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except Exception as e:
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logger.error(f"Failed to get path mappings: {e}")
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return []
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def detect_cycles(self, graph: MappingGraph) -> List[List[int]]:
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"""
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检测图中的环
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Args:
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graph: 映射图
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Returns:
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所有环的列表
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"""
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try:
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cycles = self.algorithms.detect_cycles(graph)
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if cycles:
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logger.warning(f"Detected {len(cycles)} cycles in graph")
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return cycles
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except Exception as e:
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logger.error(f"Failed to detect cycles: {e}")
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return []
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def validate_graph(self, graph: MappingGraph) -> Tuple[bool, List[str]]:
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"""
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验证图的有效性
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Args:
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graph: 映射图
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Returns:
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(是否有效, 错误信息列表)
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"""
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errors = []
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# 检查孤立节点
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isolated_nodes = []
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for node_id in graph.nodes:
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if not graph.get_edges_from(node_id) and not graph.get_edges_to(node_id):
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isolated_nodes.append(node_id)
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if isolated_nodes:
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errors.append(f"发现 {len(isolated_nodes)} 个孤立节点")
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# 检查环
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cycles = self.detect_cycles(graph)
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if cycles:
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errors.append(f"发现 {len(cycles)} 个环路")
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# 检查边的有效性
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invalid_edges = []
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for edge in graph.edges:
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if edge.source_field_id not in graph.nodes:
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invalid_edges.append(f"边 {edge.id} 的源节点不存在")
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if edge.target_field_id not in graph.nodes:
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invalid_edges.append(f"边 {edge.id} 的目标节点不存在")
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if invalid_edges:
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errors.extend(invalid_edges)
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is_valid = len(errors) == 0
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return is_valid, errors
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