Java GraphTraversal.as方法代码示例

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal; //导入方法依赖的package包/类
/**
 * @param traversal the traversal to extend with this Fragment
 * @param graph     the graph to execute the traversal on
 */
public final GraphTraversal<Vertex, ? extends Element> applyTraversal(
        GraphTraversal<Vertex, ? extends Element> traversal, GraknTx graph,
        Collection<Var> vars, @Nullable Var currentVar) {
    if (currentVar != null) {
        if (!currentVar.equals(start())) {
            if (vars.contains(start())) {
                // If the variable name has been visited but the traversal is not at that variable name, select it
                traversal.select(start().name());
            } else {
                // Restart traversal when fragments are disconnected
                traversal.V().as(start().name());
            }
        }
    } else {
        // If the variable name has not been visited yet, remember it and use the 'as' step
        traversal.as(start().name());
    }

    vars.add(start());

    traversal = applyTraversalInner(traversal, graph, vars);

    Var end = end();
    if (end != null) {
        assignVar(traversal, end, vars);
    }

    vars.addAll(vars());

    return traversal;
}
 

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal; //导入方法依赖的package包/类
static <T, U> GraphTraversal<T, U> assignVar(GraphTraversal<T, U> traversal, Var var, Collection<Var> vars) {
    if (!vars.contains(var)) {
        // This variable name has not been encountered before, remember it and use the 'as' step
        return traversal.as(var.name());
    } else {
        // This variable name has been encountered before, confirm it is the same
        return traversal.where(P.eq(var.name()));
    }
}
 

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal; //导入方法依赖的package包/类
/**
 * Optionally traverse from a {@link Schema.EdgeLabel#ROLE_PLAYER} edge to the {@link Role} it mentions, plus any super-types.
 *
 * @param traversal the traversal, starting from the {@link Schema.EdgeLabel#ROLE_PLAYER}  edge
 * @param role the variable to assign to the role. If not present, do nothing
 * @param edgeProperty the edge property to look up the role label ID
 */
static void traverseToRole(
        GraphTraversal<?, Edge> traversal, @Nullable Var role, Schema.EdgeProperty edgeProperty,
        Collection<Var> vars) {
    if (role != null) {
        Var edge = Graql.var();
        traversal.as(edge.name());
        Fragments.outSubs(Fragments.traverseSchemaConceptFromEdge(traversal, edgeProperty));
        assignVar(traversal, role, vars).select(edge.name());
    }
}