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;
021
022/**
023 * A subinterface of {@link ValueGraph} which adds mutation methods. When mutation is not required,
024 * users should prefer the {@link ValueGraph} interface.
025 *
026 * @author James Sexton
027 * @param <N> Node parameter type
028 * @param <V> Value parameter type
029 * @since 20.0
030 */
031@Beta
032public interface MutableValueGraph<N, V> extends ValueGraph<N, V> {
033
034  /**
035   * Adds {@code node} if it is not already present.
036   *
037   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
038   *
039   * @return {@code true} iff the graph was modified as a result of this call
040   */
041  @CanIgnoreReturnValue
042  boolean addNode(N node);
043
044  /**
045   * Adds an edge connecting {@code nodeU} to {@code nodeV} if one is not already present; associate
046   * that edge with {@code value}. In an undirected graph, the edge will also connect {@code nodeV}
047   * to {@code nodeU}.
048   *
049   * <p>Values do not have to be unique. However, values must be non-null.
050   *
051   * <p>Behavior if {@code nodeU} and {@code nodeV} are not already present in this graph is
052   * implementation-dependent. Suggested behaviors include (a) silently {@link #addNode(Object)
053   * adding} {@code nodeU} and {@code nodeV} to the graph (this is the behavior of the default
054   * implementations) or (b) throwing {@code IllegalArgumentException}.
055   *
056   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
057   *     nodeV}, or null if there was no such edge.
058   * @throws IllegalArgumentException if the introduction of the edge would violate {@link
059   *     #allowsSelfLoops()}
060   */
061  @CanIgnoreReturnValue
062  V putEdgeValue(N nodeU, N nodeV, V value);
063
064  /**
065   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
066   *
067   * @return {@code true} iff the graph was modified as a result of this call
068   */
069  @CanIgnoreReturnValue
070  boolean removeNode(Object node);
071
072  /**
073   * Removes the edge connecting {@code nodeU} to {@code nodeV}, if it is present.
074   *
075   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
076   *     nodeV}, or null if there was no such edge.
077   */
078  @CanIgnoreReturnValue
079  V removeEdge(Object nodeU, Object nodeV);
080}