001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.eclipse.aether.util.graph.visitor; 020 021import java.util.function.Consumer; 022 023import org.eclipse.aether.graph.DependencyNode; 024 025/** 026 * Processes dependency graph by traversing the graph in preorder. This visitor visits each node exactly once 027 * regardless how many paths within the dependency graph lead to the node such that the resulting node sequence is 028 * free of duplicates. 029 * 030 * @since TBD 031 */ 032public final class PreorderDependencyNodeConsumerVisitor extends AbstractDependencyNodeConsumerVisitor { 033 034 public static final String NAME = "preOrder"; 035 036 /** 037 * Creates a new preorder list generator. 038 */ 039 public PreorderDependencyNodeConsumerVisitor(Consumer<DependencyNode> nodeConsumer) { 040 super(nodeConsumer); 041 } 042 043 @Override 044 public boolean visitEnter(DependencyNode node) { 045 if (!setVisited(node)) { 046 return false; 047 } 048 nodeConsumer.accept(node); 049 return true; 050 } 051 052 @Override 053 public boolean visitLeave(DependencyNode node) { 054 return true; 055 } 056}