| /* |
| * Copyright 2017-present Open Networking Foundation |
| * |
| * Licensed 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.onosproject.net.topology; |
| |
| import static org.onosproject.net.Link.State.ACTIVE; |
| import static org.onosproject.net.Link.Type.INDIRECT; |
| |
| import org.onlab.graph.ScalarWeight; |
| import org.onlab.graph.Weight; |
| |
| /** |
| * Link weight for measuring link cost as hop count with indirect links |
| * being as expensive as traversing the entire graph to assume the worst. |
| */ |
| public class HopCountLinkWeigher implements LinkWeigher { |
| |
| public static final LinkWeigher DEFAULT_HOP_COUNT_WEIGHER = new HopCountLinkWeigher(); |
| |
| private static final ScalarWeight ZERO = new ScalarWeight(0.0); |
| private static final ScalarWeight ONE = new ScalarWeight(1.0); |
| private static final ScalarWeight DEFAULT_INDIRECT = new ScalarWeight(Short.MAX_VALUE); |
| |
| private final ScalarWeight indirectLinkCost; |
| |
| /** |
| * Creates a new hop-count weight. |
| */ |
| public HopCountLinkWeigher() { |
| this.indirectLinkCost = DEFAULT_INDIRECT; |
| } |
| |
| /** |
| * Creates a new hop-count weight with the specified cost of indirect links. |
| * |
| * @param indirectLinkCost indirect link cost |
| */ |
| public HopCountLinkWeigher(double indirectLinkCost) { |
| this.indirectLinkCost = new ScalarWeight(indirectLinkCost); |
| } |
| |
| @Override |
| public Weight weight(TopologyEdge edge) { |
| if (edge.link().state() == ACTIVE) { |
| return edge.link().type() == INDIRECT ? indirectLinkCost : ONE; |
| } else { |
| return getNonViableWeight(); |
| } |
| } |
| |
| @Override |
| public Weight getInitialWeight() { |
| return ZERO; |
| } |
| |
| @Override |
| public Weight getNonViableWeight() { |
| return ScalarWeight.NON_VIABLE_WEIGHT; |
| } |
| |
| } |