How to use

edgeValueOrDefault

method

in

com.google.common.graph.ValueGraph

 @Override
 public V apply(N successorNode) {
  return graph.edgeValueOrDefault(node, successorNode, null);
 }
};

 @Override
 public V apply(N successorNode) {
  return graph.edgeValueOrDefault(node, successorNode, null);
 }
};

 @Override
 public V apply(N successorNode) {
  return graph.edgeValueOrDefault(node, successorNode, null);
 }
};

 @Override
 public V apply(EndpointPair<N> edge) {
  return graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null);
 }
};

 @Override
 public @Nullable V edgeValueOrDefault(EndpointPair<N> endpoints, @Nullable V defaultValue) {
  return delegate().edgeValueOrDefault(endpoints, defaultValue);
 }
}

@Override
public @Nullable V edgeValueOrDefault(N nodeU, N nodeV, @Nullable V defaultValue) {
 return delegate().edgeValueOrDefault(nodeV, nodeU, defaultValue); // transpose
}

@Override
public @Nullable V edgeValueOrDefault(N nodeU, N nodeV, @Nullable V defaultValue) {
 return delegate().edgeValueOrDefault(nodeU, nodeV, defaultValue);
}

 @Override
 public V apply(EndpointPair<N> edge) {
  return graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null);
 }
};

 @Override
 public @Nullable V edgeValueOrDefault(EndpointPair<N> endpoints, @Nullable V defaultValue) {
  return delegate().edgeValueOrDefault(transpose(endpoints), defaultValue);
 }
}

 @Override
 public V apply(EndpointPair<N> edge) {
  return graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null);
 }
};

 @Override
 @NullableDecl
 public V edgeValueOrDefault(N nodeU, N nodeV, @NullableDecl V defaultValue) {
  return delegate().edgeValueOrDefault(nodeV, nodeU, defaultValue); // transpose
 }
}

 @Override
 @NullableDecl
 public V edgeValueOrDefault(N nodeU, N nodeV, @NullableDecl V defaultValue) {
  return delegate().edgeValueOrDefault(nodeU, nodeV, defaultValue);
 }
}

 @Override
 @NullableDecl
 public V edgeValueOrDefault(N nodeU, N nodeV, @NullableDecl V defaultValue) {
  return delegate().edgeValueOrDefault(nodeU, nodeV, defaultValue);
 }
}

 @Override
 @NullableDecl
 public V edgeValueOrDefault(N nodeU, N nodeV, @NullableDecl V defaultValue) {
  return delegate().edgeValueOrDefault(nodeV, nodeU, defaultValue); // transpose
 }
}

/**
 * Returns the subgraph of {@code graph} induced by {@code nodes}. This subgraph is a new graph
 * that contains all of the nodes in {@code nodes}, and all of the {@link Graph#edges() edges}
 * (and associated edge values) from {@code graph} for which both nodes are contained by {@code
 * nodes}.
 *
 * @throws IllegalArgumentException if any element in {@code nodes} is not a node in the graph
 */
public static <N, V> MutableValueGraph<N, V> inducedSubgraph(
  ValueGraph<N, V> graph, Iterable<? extends N> nodes) {
 MutableValueGraph<N, V> subgraph =
   (nodes instanceof Collection)
     ? ValueGraphBuilder.from(graph).expectedNodeCount(((Collection) nodes).size()).build()
     : ValueGraphBuilder.from(graph).build();
 for (N node : nodes) {
  subgraph.addNode(node);
 }
 for (N node : subgraph.nodes()) {
  for (N successorNode : graph.successors(node)) {
   if (subgraph.nodes().contains(successorNode)) {
    subgraph.putEdgeValue(
      node, successorNode, graph.edgeValueOrDefault(node, successorNode, null));
   }
  }
 }
 return subgraph;
}

/** Creates a mutable copy of {@code graph} with the same nodes, edges, and edge values. */
public static <N, V> MutableValueGraph<N, V> copyOf(ValueGraph<N, V> graph) {
 MutableValueGraph<N, V> copy =
   ValueGraphBuilder.from(graph).expectedNodeCount(graph.nodes().size()).build();
 for (N node : graph.nodes()) {
  copy.addNode(node);
 }
 for (EndpointPair<N> edge : graph.edges()) {
  copy.putEdgeValue(
    edge.nodeU(), edge.nodeV(), graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null));
 }
 return copy;
}

/**
 * Returns the subgraph of {@code graph} induced by {@code nodes}. This subgraph is a new graph
 * that contains all of the nodes in {@code nodes}, and all of the {@link Graph#edges() edges}
 * (and associated edge values) from {@code graph} for which both nodes are contained by {@code
 * nodes}.
 *
 * @throws IllegalArgumentException if any element in {@code nodes} is not a node in the graph
 */
public static <N, V> MutableValueGraph<N, V> inducedSubgraph(
  ValueGraph<N, V> graph, Iterable<? extends N> nodes) {
 MutableValueGraph<N, V> subgraph =
   (nodes instanceof Collection)
     ? ValueGraphBuilder.from(graph).expectedNodeCount(((Collection) nodes).size()).build()
     : ValueGraphBuilder.from(graph).build();
 for (N node : nodes) {
  subgraph.addNode(node);
 }
 for (N node : subgraph.nodes()) {
  for (N successorNode : graph.successors(node)) {
   if (subgraph.nodes().contains(successorNode)) {
    subgraph.putEdgeValue(
      node, successorNode, graph.edgeValueOrDefault(node, successorNode, null));
   }
  }
 }
 return subgraph;
}

/** Creates a mutable copy of {@code graph} with the same nodes, edges, and edge values. */
public static <N, V> MutableValueGraph<N, V> copyOf(ValueGraph<N, V> graph) {
 MutableValueGraph<N, V> copy =
   ValueGraphBuilder.from(graph).expectedNodeCount(graph.nodes().size()).build();
 for (N node : graph.nodes()) {
  copy.addNode(node);
 }
 for (EndpointPair<N> edge : graph.edges()) {
  copy.putEdgeValue(
    edge.nodeU(), edge.nodeV(), graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null));
 }
 return copy;
}

/** Creates a mutable copy of {@code graph} with the same nodes, edges, and edge values. */
public static <N, V> MutableValueGraph<N, V> copyOf(ValueGraph<N, V> graph) {
 MutableValueGraph<N, V> copy =
   ValueGraphBuilder.from(graph).expectedNodeCount(graph.nodes().size()).build();
 for (N node : graph.nodes()) {
  copy.addNode(node);
 }
 for (EndpointPair<N> edge : graph.edges()) {
  copy.putEdgeValue(
    edge.nodeU(), edge.nodeV(), graph.edgeValueOrDefault(edge.nodeU(), edge.nodeV(), null));
 }
 return copy;
}

@Test
public void transpose_directedValueGraph() {
 MutableValueGraph<Integer, String> directedGraph =
   ValueGraphBuilder.directed().allowsSelfLoops(true).build();
 directedGraph.putEdgeValue(N1, N3, E13);
 directedGraph.putEdgeValue(N3, N1, E31);
 directedGraph.putEdgeValue(N1, N2, E12);
 directedGraph.putEdgeValue(N1, N1, E11);
 directedGraph.putEdgeValue(N3, N4, E34);
 MutableValueGraph<Integer, String> expectedTranspose =
   ValueGraphBuilder.directed().allowsSelfLoops(true).build();
 expectedTranspose.putEdgeValue(N3, N1, E13);
 expectedTranspose.putEdgeValue(N1, N3, E31);
 expectedTranspose.putEdgeValue(N2, N1, E12);
 expectedTranspose.putEdgeValue(N1, N1, E11);
 expectedTranspose.putEdgeValue(N4, N3, E34);
 ValueGraph<Integer, String> transpose = transpose(directedGraph);
 assertThat(transpose).isEqualTo(expectedTranspose);
 assertThat(transpose(transpose)).isSameAs(directedGraph);
 AbstractGraphTest.validateGraph(transpose.asGraph());
 assertThat(transpose.edgeValueOrDefault(N1, N2, null)).isNull();
 for (Integer node : directedGraph.nodes()) {
  assertThat(directedGraph.inDegree(node)).isSameAs(transpose.outDegree(node));
  assertThat(directedGraph.outDegree(node)).isSameAs(transpose.inDegree(node));
 }
 directedGraph.putEdgeValue(N2, N1, E21);
 // View should be updated.
 assertThat(transpose.edgeValueOrDefault(N1, N2, null)).isEqualTo(E21);
 AbstractGraphTest.validateGraph(transpose.asGraph());
}