CrazyHZM commented on code in PR #1208: URL: https://github.com/apache/maven/pull/1208#discussion_r1305099150
########## maven-core/src/main/java/org/apache/maven/utils/dag/CycleDetector.java: ########## @@ -0,0 +1,136 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.maven.utils.dag; + +import java.util.Collections; +import java.util.HashMap; +import java.util.LinkedList; +import java.util.List; +import java.util.Map; + +/** + * @author <a href="michal.mac...@dimatics.com">Michal Maczka</a> + * + */ +public class CycleDetector { + + private static final Integer NOT_VISITED = 0; + + private static final Integer VISITING = 1; + + private static final Integer VISITED = 2; + + public static List<String> hasCycle(final DAG graph) { + final List<Vertex> vertices = graph.getVertices(); + + final Map<Vertex, Integer> vertexStateMap = new HashMap<>(); + + List<String> retValue = null; + + for (Vertex vertex : vertices) { + if (isNotVisited(vertex, vertexStateMap)) { + retValue = introducesCycle(vertex, vertexStateMap); + + if (retValue != null) { + break; + } + } + } + + return retValue; + } + + /** + * This method will be called when an edge leading to given vertex was added and we want to check if introduction of + * this edge has not resulted in apparition of cycle in the graph + * + * @param vertex the vertex + * @param vertexStateMap the vertex Map + * @return the found cycle + */ + public static List<String> introducesCycle(final Vertex vertex, final Map<Vertex, Integer> vertexStateMap) { Review Comment: change to `private`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@maven.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
