1 /* 2 * Copyright (C) 2016 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.graph; 18 19 import com.google.errorprone.annotations.CanIgnoreReturnValue; 20 import java.util.Iterator; 21 import java.util.Set; 22 import javax.annotation.CheckForNull; 23 24 /** 25 * An interface for representing and manipulating an origin node's adjacent nodes and edge values in 26 * a {@link Graph}. 27 * 28 * @author James Sexton 29 * @param <N> Node parameter type 30 * @param <V> Value parameter type 31 */ 32 @ElementTypesAreNonnullByDefault 33 interface GraphConnections<N, V> { 34 adjacentNodes()35 Set<N> adjacentNodes(); 36 predecessors()37 Set<N> predecessors(); 38 successors()39 Set<N> successors(); 40 41 /** 42 * Returns an iterator over the incident edges. 43 * 44 * @param thisNode The node that this all of the connections in this class are connected to. 45 */ incidentEdgeIterator(N thisNode)46 Iterator<EndpointPair<N>> incidentEdgeIterator(N thisNode); 47 48 /** 49 * Returns the value associated with the edge connecting the origin node to {@code node}, or null 50 * if there is no such edge. 51 */ 52 @CheckForNull value(N node)53 V value(N node); 54 55 /** Remove {@code node} from the set of predecessors. */ removePredecessor(N node)56 void removePredecessor(N node); 57 58 /** 59 * Remove {@code node} from the set of successors. Returns the value previously associated with 60 * the edge connecting the two nodes. 61 */ 62 @CanIgnoreReturnValue 63 @CheckForNull removeSuccessor(N node)64 V removeSuccessor(N node); 65 66 /** 67 * Add {@code node} as a predecessor to the origin node. In the case of an undirected graph, it 68 * also becomes a successor. Associates {@code value} with the edge connecting the two nodes. 69 */ addPredecessor(N node, V value)70 void addPredecessor(N node, V value); 71 72 /** 73 * Add {@code node} as a successor to the origin node. In the case of an undirected graph, it also 74 * becomes a predecessor. Associates {@code value} with the edge connecting the two nodes. Returns 75 * the value previously associated with the edge connecting the two nodes. 76 */ 77 @CanIgnoreReturnValue 78 @CheckForNull addSuccessor(N node, V value)79 V addSuccessor(N node, V value); 80 } 81