| /* |
| * Copyright (C) 2016 The Guava Authors |
| * |
| * 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 com.google.common.graph; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkState; |
| |
| import java.util.Collections; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * A base implementation of {@link NetworkConnections} for undirected networks. |
| * |
| * @author James Sexton |
| * @param <N> Node parameter type |
| * @param <E> Edge parameter type |
| */ |
| abstract class AbstractUndirectedNetworkConnections<N, E> implements NetworkConnections<N, E> { |
| /** Keys are edges incident to the origin node, values are the node at the other end. */ |
| protected final Map<E, N> incidentEdgeMap; |
| |
| protected AbstractUndirectedNetworkConnections(Map<E, N> incidentEdgeMap) { |
| this.incidentEdgeMap = checkNotNull(incidentEdgeMap); |
| } |
| |
| @Override |
| public Set<N> predecessors() { |
| return adjacentNodes(); |
| } |
| |
| @Override |
| public Set<N> successors() { |
| return adjacentNodes(); |
| } |
| |
| @Override |
| public Set<E> incidentEdges() { |
| return Collections.unmodifiableSet(incidentEdgeMap.keySet()); |
| } |
| |
| @Override |
| public Set<E> inEdges() { |
| return incidentEdges(); |
| } |
| |
| @Override |
| public Set<E> outEdges() { |
| return incidentEdges(); |
| } |
| |
| @Override |
| public N adjacentNode(E edge) { |
| return checkNotNull(incidentEdgeMap.get(edge)); |
| } |
| |
| @Override |
| public N removeInEdge(E edge, boolean isSelfLoop) { |
| if (!isSelfLoop) { |
| return removeOutEdge(edge); |
| } |
| return null; |
| } |
| |
| @Override |
| public N removeOutEdge(E edge) { |
| N previousNode = incidentEdgeMap.remove(edge); |
| return checkNotNull(previousNode); |
| } |
| |
| @Override |
| public void addInEdge(E edge, N node, boolean isSelfLoop) { |
| if (!isSelfLoop) { |
| addOutEdge(edge, node); |
| } |
| } |
| |
| @Override |
| public void addOutEdge(E edge, N node) { |
| N previousNode = incidentEdgeMap.put(edge, node); |
| checkState(previousNode == null); |
| } |
| } |