001/*
002 * Copyright (C) 2016 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.graph;
018
019import com.google.common.annotations.Beta;
020import com.google.errorprone.annotations.CanIgnoreReturnValue;
021import javax.annotation.CheckForNull;
022
023/**
024 * A subinterface of {@link ValueGraph} which adds mutation methods. When mutation is not required,
025 * users should prefer the {@link ValueGraph} interface.
026 *
027 * @author James Sexton
028 * @param <N> Node parameter type
029 * @param <V> Value parameter type
030 * @since 20.0
031 */
032@Beta
033public interface MutableValueGraph<N, V> extends ValueGraph<N, V> {
034
035  /**
036   * Adds {@code node} if it is not already present.
037   *
038   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
039   *
040   * @return {@code true} if the graph was modified as a result of this call
041   */
042  @CanIgnoreReturnValue
043  boolean addNode(N node);
044
045  /**
046   * Adds an edge connecting {@code nodeU} to {@code nodeV} if one is not already present, and sets
047   * a value for that edge to {@code value} (overwriting the existing value, if any).
048   *
049   * <p>If the graph is directed, the resultant edge will be directed; otherwise, it will be
050   * undirected.
051   *
052   * <p>Values do not have to be unique. However, values must be non-null.
053   *
054   * <p>If {@code nodeU} and {@code nodeV} are not already present in this graph, this method will
055   * silently {@link #addNode(Object) add} {@code nodeU} and {@code nodeV} to the graph.
056   *
057   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
058   *     nodeV}, or null if there was no such edge.
059   * @throws IllegalArgumentException if the introduction of the edge would violate {@link
060   *     #allowsSelfLoops()}
061   */
062  @CanIgnoreReturnValue
063  @CheckForNull
064  V putEdgeValue(N nodeU, N nodeV, V value);
065
066  /**
067   * Adds an edge connecting {@code endpoints} if one is not already present, and sets a value for
068   * that edge to {@code value} (overwriting the existing value, if any).
069   *
070   * <p>If the graph is directed, the resultant edge will be directed; otherwise, it will be
071   * undirected.
072   *
073   * <p>If this graph is directed, {@code endpoints} must be ordered.
074   *
075   * <p>Values do not have to be unique. However, values must be non-null.
076   *
077   * <p>If either or both endpoints are not already present in this graph, this method will silently
078   * {@link #addNode(Object) add} each missing endpoint to the graph.
079   *
080   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
081   *     nodeV}, or null if there was no such edge.
082   * @throws IllegalArgumentException if the introduction of the edge would violate {@link
083   *     #allowsSelfLoops()}
084   * @throws IllegalArgumentException if the endpoints are unordered and the graph is directed
085   * @since 27.1
086   */
087  @CanIgnoreReturnValue
088  @CheckForNull
089  V putEdgeValue(EndpointPair<N> endpoints, V value);
090
091  /**
092   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
093   *
094   * @return {@code true} if the graph was modified as a result of this call
095   */
096  @CanIgnoreReturnValue
097  boolean removeNode(N node);
098
099  /**
100   * Removes the edge connecting {@code nodeU} to {@code nodeV}, if it is present.
101   *
102   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
103   *     nodeV}, or null if there was no such edge.
104   */
105  @CanIgnoreReturnValue
106  @CheckForNull
107  V removeEdge(N nodeU, N nodeV);
108
109  /**
110   * Removes the edge connecting {@code endpoints}, if it is present.
111   *
112   * <p>If this graph is directed, {@code endpoints} must be ordered.
113   *
114   * @return the value previously associated with the edge connecting {@code endpoints}, or null if
115   *     there was no such edge.
116   * @since 27.1
117   */
118  @CanIgnoreReturnValue
119  @CheckForNull
120  V removeEdge(EndpointPair<N> endpoints);
121}