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 com.google.errorprone.annotations.CompatibleWith;
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; associate
047   * that edge with {@code value}. In an undirected graph, the edge will also connect {@code nodeV}
048   * to {@code nodeU}.
049   *
050   * <p>Values do not have to be unique. However, values must be non-null.
051   *
052   * <p>Behavior if {@code nodeU} and {@code nodeV} are not already present in this graph is
053   * implementation-dependent. Suggested behaviors include (a) silently {@link #addNode(Object)
054   * adding} {@code nodeU} and {@code nodeV} to the graph (this is the behavior of the default
055   * implementations) or (b) throwing {@code IllegalArgumentException}.
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  V putEdgeValue(N nodeU, N nodeV, V value);
064
065  /**
066   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
067   *
068   * @return {@code true} if the graph was modified as a result of this call
069   */
070  @CanIgnoreReturnValue
071  boolean removeNode(@CompatibleWith("N") Object node);
072
073  /**
074   * Removes the edge connecting {@code nodeU} to {@code nodeV}, if it is present.
075   *
076   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
077   *     nodeV}, or null if there was no such edge.
078   */
079  @CanIgnoreReturnValue
080  V removeEdge(@CompatibleWith("N") Object nodeU, @CompatibleWith("N") Object nodeV);
081}