| /* |
| * Copyright (C) 2017 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 java.util.Set; |
| |
| /** |
| * A non-public interface for the methods shared between {@link Graph} and {@link ValueGraph}. |
| * |
| * @author James Sexton |
| * @param <N> Node parameter type |
| */ |
| interface BaseGraph<N> extends SuccessorsFunction<N>, PredecessorsFunction<N> { |
| // |
| // Graph-level accessors |
| // |
| |
| /** Returns all nodes in this graph, in the order specified by {@link #nodeOrder()}. */ |
| Set<N> nodes(); |
| |
| /** Returns all edges in this graph. */ |
| Set<EndpointPair<N>> edges(); |
| |
| // |
| // Graph properties |
| // |
| |
| /** |
| * Returns true if the edges in this graph are directed. Directed edges connect a {@link |
| * EndpointPair#source() source node} to a {@link EndpointPair#target() target node}, while |
| * undirected edges connect a pair of nodes to each other. |
| */ |
| boolean isDirected(); |
| |
| /** |
| * Returns true if this graph allows self-loops (edges that connect a node to itself). Attempting |
| * to add a self-loop to a graph that does not allow them will throw an {@link |
| * IllegalArgumentException}. |
| */ |
| boolean allowsSelfLoops(); |
| |
| /** Returns the order of iteration for the elements of {@link #nodes()}. */ |
| ElementOrder<N> nodeOrder(); |
| |
| // |
| // Element-level accessors |
| // |
| |
| /** |
| * Returns the nodes which have an incident edge in common with {@code node} in this graph. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| Set<N> adjacentNodes(N node); |
| |
| /** |
| * Returns all nodes in this graph adjacent to {@code node} which can be reached by traversing |
| * {@code node}'s incoming edges <i>against</i> the direction (if any) of the edge. |
| * |
| * <p>In an undirected graph, this is equivalent to {@link #adjacentNodes(Object)}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| @Override |
| Set<N> predecessors(N node); |
| |
| /** |
| * Returns all nodes in this graph adjacent to {@code node} which can be reached by traversing |
| * {@code node}'s outgoing edges in the direction (if any) of the edge. |
| * |
| * <p>In an undirected graph, this is equivalent to {@link #adjacentNodes(Object)}. |
| * |
| * <p>This is <i>not</i> the same as "all nodes reachable from {@code node} by following outgoing |
| * edges". For that functionality, see {@link Graphs#reachableNodes(Graph, Object)}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| @Override |
| Set<N> successors(N node); |
| |
| /** |
| * Returns the edges in this graph whose endpoints include {@code node}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| * @since 24.0 |
| */ |
| Set<EndpointPair<N>> incidentEdges(N node); |
| |
| /** |
| * Returns the count of {@code node}'s incident edges, counting self-loops twice (equivalently, |
| * the number of times an edge touches {@code node}). |
| * |
| * <p>For directed graphs, this is equal to {@code inDegree(node) + outDegree(node)}. |
| * |
| * <p>For undirected graphs, this is equal to {@code incidentEdges(node).size()} + (number of |
| * self-loops incident to {@code node}). |
| * |
| * <p>If the count is greater than {@code Integer.MAX_VALUE}, returns {@code Integer.MAX_VALUE}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| int degree(N node); |
| |
| /** |
| * Returns the count of {@code node}'s incoming edges (equal to {@code predecessors(node).size()}) |
| * in a directed graph. In an undirected graph, returns the {@link #degree(Object)}. |
| * |
| * <p>If the count is greater than {@code Integer.MAX_VALUE}, returns {@code Integer.MAX_VALUE}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| int inDegree(N node); |
| |
| /** |
| * Returns the count of {@code node}'s outgoing edges (equal to {@code successors(node).size()}) |
| * in a directed graph. In an undirected graph, returns the {@link #degree(Object)}. |
| * |
| * <p>If the count is greater than {@code Integer.MAX_VALUE}, returns {@code Integer.MAX_VALUE}. |
| * |
| * @throws IllegalArgumentException if {@code node} is not an element of this graph |
| */ |
| int outDegree(N node); |
| |
| /** |
| * Returns true if there is an edge that directly connects {@code nodeU} to {@code nodeV}. This is |
| * equivalent to {@code nodes().contains(nodeU) && successors(nodeU).contains(nodeV)}. |
| * |
| * <p>In an undirected graph, this is equal to {@code hasEdgeConnecting(nodeV, nodeU)}. |
| * |
| * @since 23.0 |
| */ |
| boolean hasEdgeConnecting(N nodeU, N nodeV); |
| |
| /** |
| * Returns true if there is an edge that directly connects {@code endpoints} (in the order, if |
| * any, specified by {@code endpoints}). This is equivalent to {@code |
| * edges().contains(endpoints)}. |
| * |
| * <p>Unlike the other {@code EndpointPair}-accepting methods, this method does not throw if the |
| * endpoints are unordered; it simply returns false. This is for consistency with the behavior of |
| * {@link Collection#contains(Object)} (which does not generally throw if the object cannot be |
| * present in the collection), and the desire to have this method's behavior be compatible with |
| * {@code edges().contains(endpoints)}. |
| * |
| * @since 27.1 |
| */ |
| boolean hasEdgeConnecting(EndpointPair<N> endpoints); |
| } |