[英]Arangodb Java-driver Sort paths
Please, can you explain me how I can sort paths.请你解释一下我如何对路径进行排序。 Now I have next code
现在我有下一个代码
TraversalOptions options = new TraversalOptions()
.edgeCollection("edges")
.startVertex("nodes/9149892904413851091")
.verticesUniqueness(TraversalOptions.UniquenessType.path)
.direction(TraversalOptions.Direction.any)
.strategy(TraversalOptions.Strategy.depthfirst)
.order(TraversalOptions.Order.preorder)
.minDepth(5)
.maxDepth(5);
System.out.println("1");
TraversalEntity<BaseDocument, BaseEdgeDocument> traversal =
db.executeTraversal(BaseDocument.class, BaseEdgeDocument.class, options);
How I understand .sort
method in options will sort edges.我如何理解选项中的
.sort
方法将对边缘进行排序。 But I want to sort paths.但我想对路径进行排序。 Any ideas?
有任何想法吗?
I need to test two cases: 1. sort by length of paths ( so I will find the shortest path) 2. sort by sum of relationships' weights (so i will be able to find a path with the less weight)我需要测试两种情况:1. 按路径长度排序(所以我会找到最短路径) 2. 按关系权重的总和排序(所以我将能够找到权重较小的路径)
Achieving your goal is both easier and much more efficient using an AQL query than a Traversal.使用 AQL 查询比使用遍历更容易、更高效地实现您的目标。
A (parameterized) AQL query for a shortest path looks like this:最短路径的(参数化)AQL 查询如下所示:
FOR v IN ANY SHORTEST_PATH
@startVertex TO @targetVertex
edges
RETURN v
To get a weighted shortest path (ie, shortest in terms of sum of the weights), just specify the name of the weight attribute:要获得加权最短路径(即权重总和最短),只需指定权重属性的名称:
FOR v IN ANY SHORTEST_PATH
@startVertex TO @targetVertex
edges
OPTIONS { weightAttribute: "weight" }
RETURN v
You can use an AQL query in Java like this:您可以像这样在 Java 中使用 AQL 查询:
// Set the query parameters
Map<String, Object> bindVars
= new MapBuilder()
.put("startVertex", "nodes/1234")
.put("targetVertex", "nodes/5678")
.get();
// execute the query
ArangoCursor<BaseDocument> cursor = arango.db("mydb").query(
"FOR v IN ANY SHORTEST_PATH "
+ "@startVertex TO @targetVertex "
+ "edges "
+ "OPTIONS { weightAttribute: 'weight' } "
+ "RETURN v",
bindVars,
null,
BaseDocument.class
);
// do something with the results
cursor.forEach((v) -> {
System.out.println(v);
});
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