How to use

toCollection

method

in

org.gephi.graph.api.NodeIterable

public static Node[] getPredecessors(DirectedGraph graph, Node[] nodes) {
  Set<Node> nodeTree = new HashSet<>();
  graph.readLock();
  try {
    for (Node n : nodes) {
      nodeTree.addAll(graph.getPredecessors(n).toCollection());
    }
  } finally {
    graph.readUnlock();
  }
  //remove original nodes
  for (Node n : nodes) {
    nodeTree.remove(n);
  }
  return nodeTree.toArray(new Node[0]);
}

public static Node[] getNeighbors(Graph graph, Node[] nodes) {
  Set<Node> nodeTree = new HashSet<>();
  
  graph.readLock();
  try {
    for (Node n : nodes) {
      nodeTree.addAll(graph.getNeighbors(n).toCollection());
    }
  } finally {
    graph.readUnlock();
  }
  //remove original nodes
  for (Node n : nodes) {
    nodeTree.remove(n);
  }
  return nodeTree.toArray(new Node[0]);
}

public static Node[] getSuccessors(DirectedGraph graph, Node[] nodes) {
  Set<Node> nodeTree = new HashSet<>();
  graph.readLock();
  try {
    for (Node n : nodes) {
      nodeTree.addAll(graph.getSuccessors(n).toCollection());
    }
  } finally {
    graph.readUnlock();
  }
  //remove original nodes
  for (Node n : nodes) {
    nodeTree.remove(n);
  }
  return nodeTree.toArray(new Node[0]);
}

public static Node[] getNeighborsOfNeighbors(Graph graph, Node[] nodes) {
  Set<Node> nodeTree = new HashSet<>();
  graph.readLock();
  try {
    for (Node n : nodes) {
      nodeTree.addAll(graph.getNeighbors(n).toCollection());
    }
    //remove original nodes
    for (Node n : nodes) {
      nodeTree.remove(n);
    }
    for (Node n : nodeTree.toArray(new Node[0])) {
      nodeTree.addAll(graph.getNeighbors(n).toCollection());
    }
  } finally {
    graph.readUnlock();
  }
  //remove original nodes
  for (Node n : nodes) {
    nodeTree.remove(n);
  }
  return nodeTree.toArray(new Node[0]);
}

topology[node_index] = new ArrayList<>();
Set<Node> uniqueNeighbors = new HashSet<>(graph.getNeighbors(node).toCollection());
for (Node neighbor : uniqueNeighbors) {
  if (node == neighbor) {

Collection<Node> nodes = graph.getNodes().toCollection();