Implementation of Adjacency list of a graph

I am trying to implement the adjacency list for a non-weighted graph and a few questions/concerns. i realize I need a linked list to store the edges and an array to store the vertices.Currently I have a (basic)Node class and a Graph class, which takes care of the addition of the edges to a particular vertex. This however does not explicitly define a linked list for the edges. I want to do a DFS and BFS and was wondering how should I go about it? Do I need to changed the code that I already have to incorporate 开发者_Go百科these methods or now. Help will be appreciated.

 // Inside the graph class

  public boolean insertNode(NodeRecord n) {
    int j;

    if (isFull()) return false;
    for (j=0; j<arraySize; j++)
        if (node[j]==null)
            break;
    node[j] = new Node(n);
    graphSize++;
    return true;
}
public boolean insertEdge(int nodeID, EdgeRecord e) {
    int j;

    for (j=0; j<arraySize; j++)
        if (nodeID==((NodeRecord) node[j].item).getID())
            break;
    if (j>=arraySize) return false;
    node[j].next = new Node(e, node[j].next);
            return true;
}

 // inside the node class

    class Node<E> {
   E    item;
   Node<E> next;

Node(E e) {
        item = e;
        next = null;
}

Node(E e, Node<E> newNext) {
        item = e;
        next = newNext;
}

Node(Node<E> n) {  // copy constructor
        item = n.item;
        next = n.next;
 }

 }

   public static void depthFirst(){

    for(int i=0;i<mygraph.arraySize;i++){
        Node counter =mygraph.node[i];
        while(counter!=null){
         System.out.println(" " +counter.item);
         counter= counter.next;
       }

    }
}

A few notes on your code:

1. You use fixed size array to store your nodes. Switch to an arraylist which grows automatically while adding new nodes.

2. Do I understand correctly that you may only have a single edge leaving your node (next)? You should also use a list here.

3. As long as your graph is not directed take care that an edge running from A to B also goes from B to A and thus you have to add it to edge-lists of node A and node B.