/*
 * Copyright (C) 2016 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.graph.GraphConstants.Presence;

Configurable implementation of MutableGraph that supports both directed and undirected graphs. Instances of this class should be constructed with GraphBuilder. 
Time complexities for mutation methods are all O(1) except for removeNode(N node), which is in O(d_node) where d_node is the degree of node. 
Author:
James Sexton
Type parameters:
<N> – Node parameter type/**
 * Configurable implementation of {@link MutableGraph} that supports both directed and undirected
 * graphs. Instances of this class should be constructed with {@link GraphBuilder}.
 *
 * <p>Time complexities for mutation methods are all O(1) except for {@code removeNode(N node)},
 * which is in O(d_node) where d_node is the degree of {@code node}.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 */
final class ConfigurableMutableGraph<N> extends ForwardingGraph<N> implements MutableGraph<N> {
  private final MutableValueGraph<N, Presence> backingValueGraph;

  
Constructs a MutableGraph with the properties specified in builder. /** Constructs a {@link MutableGraph} with the properties specified in {@code builder}. */
  ConfigurableMutableGraph(AbstractGraphBuilder<? super N> builder) {
    this.backingValueGraph = new ConfigurableMutableValueGraph<>(builder);
  }

  @Override
  protected BaseGraph<N> delegate() {
    return backingValueGraph;
  }

  @Override
  public boolean addNode(N node) {
    return backingValueGraph.addNode(node);
  }

  @Override
  public boolean putEdge(N nodeU, N nodeV) {
    return backingValueGraph.putEdgeValue(nodeU, nodeV, Presence.EDGE_EXISTS) == null;
  }

  @Override
  public boolean removeNode(N node) {
    return backingValueGraph.removeNode(node);
  }

  @Override
  public boolean removeEdge(N nodeU, N nodeV) {
    return backingValueGraph.removeEdge(nodeU, nodeV) != null;
  }
}