1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package org.eclipse.aether.util.graph.visitor; 20 21 import java.util.function.Consumer; 22 23 import org.eclipse.aether.ConfigurationProperties; 24 import org.eclipse.aether.graph.DependencyNode; 25 26 /** 27 * Processes dependency graph by traversing the graph in preorder. This visitor visits each node exactly once 28 * regardless how many paths within the dependency graph lead to the node such that the resulting node sequence is 29 * free of duplicates. 30 * 31 * @since 2.0.0 32 */ 33 public final class PreorderDependencyNodeConsumerVisitor extends AbstractDependencyNodeConsumerVisitor { 34 35 public static final String NAME = ConfigurationProperties.REPOSITORY_SYSTEM_DEPENDENCY_VISITOR_PREORDER; 36 37 /** 38 * Creates a new preorder list generator. 39 */ 40 public PreorderDependencyNodeConsumerVisitor(Consumer<DependencyNode> nodeConsumer) { 41 super(nodeConsumer); 42 } 43 44 @Override 45 public boolean visitEnter(DependencyNode node) { 46 if (!setVisited(node)) { 47 return false; 48 } 49 nodeConsumer.accept(node); 50 return true; 51 } 52 53 @Override 54 public boolean visitLeave(DependencyNode node) { 55 return true; 56 } 57 }