https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
/*
 * Copyright (C) 2014 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 com.google.common.annotations.Beta;
import com.google.errorprone.annotations.CanIgnoreReturnValue;


A subinterface of Network which adds mutation methods. When mutation is not required, users should prefer the Network interface. 
Author:James Sexton, Joshua O'Madadhain
Type parameters:
  • <N> – Node parameter type
  • <E> – Edge parameter type
Since:20.0
/**
 * A subinterface of {@link Network} which adds mutation methods. When mutation is not required,
 * users should prefer the {@link Network} interface.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 * @since 20.0
 */
@Beta
public interface MutableNetwork<N, E> extends Network<N, E> {

  
Adds node if it is not already present. 
Nodes must be unique, just as Map keys must be. They must also be non-null. 
Returns:true if the network was modified as a result of this call
/**
   * Adds {@code node} if it is not already present.
   *
   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean addNode(N node);

  
Adds edge connecting nodeU to nodeV. In an undirected network, the edge will also connect nodeV to nodeU. 
Edges must be unique, just as Map keys must be. They must also be non-null. 
If nodeU and nodeV are not already present in this graph, this method will silently add nodeU and nodeV to the graph. 
If edge already connects nodeU to nodeV (in the specified order if this network Network.isDirected(), else in any order), then this method will have no effect. 
Throws:
Returns:true if the network was modified as a result of this call
/**
   * Adds {@code edge} connecting {@code nodeU} to {@code nodeV}. In an undirected network, the edge
   * will also connect {@code nodeV} to {@code nodeU}.
   *
   * <p><b>Edges must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
   *
   * <p>If {@code nodeU} and {@code nodeV} are not already present in this graph, this method will
   * silently {@link #addNode(Object) add} {@code nodeU} and {@code nodeV} to the graph.
   *
   * <p>If {@code edge} already connects {@code nodeU} to {@code nodeV} (in the specified order if
   * this network {@link #isDirected()}, else in any order), then this method will have no effect.
   *
   * @return {@code true} if the network was modified as a result of this call
   * @throws IllegalArgumentException if {@code edge} already exists and does not connect {@code
   *     nodeU} to {@code nodeV}, or if the introduction of the edge would violate {@link
   *     #allowsParallelEdges()} or {@link #allowsSelfLoops()}
   */
  @CanIgnoreReturnValue
  boolean addEdge(N nodeU, N nodeV, E edge);

  
Removes node if it is present; all edges incident to node will also be removed. 
Returns:true if the network was modified as a result of this call
/**
   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeNode(N node);

  
Removes edge from this network, if it is present. 
Returns:true if the network was modified as a result of this call
/**
   * Removes {@code edge} from this network, if it is present.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeEdge(E edge);
}