Help with static method issue.

Hi everyone,
There's a recent thread on the forum along a similar vein as this one but I hope mine doesn't cause as much annoyance! My homework assignment involves implementing three interfaces provided by my professor in order to create weighted, undirected graphs. The classes I have to implement are Node, Edge and Graph. Here are the Edge and Node interfaces for reference; they weren't too hard to implement:
public interface Edge {
     public Edge createEdge(String name, int ID, float weight);
     public Node getStartNode();
     public void setStartNode(Node n);
     public Node getEndNode();
     public void setEndNode(Node n);
     public String getName();
     public int getID();
     public float getWeight();
     public String toString();
public interface Node {
     public Node createNode(String name, int ID, float weight);
     public Node[] getNeighbours();
     public Edge[] getEdges();
     public void addEdge(Edge e);
     public void removeEdge(Edge e);
     public String getName();
     public int getID();
     public float getWeight();
     public String toString();
}Now, one of the graphs I should be aiming to create is this one ( [http://i35.tinypic.com/2iqn62d.gif|http://i35.tinypic.com/2iqn62d.gif] ) so I apologize for the code I'm about to show and its length. It's the Graph class:
import java.util.ArrayList;
public class Graph {
     public static void main(String [] args) {
          // Create all nodes
          int i = 1;
          Node food = new Node();
          food.createNode("Food", i, 0);
          i++;
          Node healthy = new Node();
          healthy.createNode("Healthy", i, 4f);
          i++;
          Node neutral = new Node();
          neutral.createNode("Neutral", i, 0);
          i++;
          Node unhealthy = new Node();
          unhealthy.createNode("Unhealthy", i, -4f);
          i++;
          Node orange = new Node();
          orange.createNode("Orange", i, 6f);
          i++;
          Node cabbage = new Node();
          unhealthy.createNode("Cabbage", i, 3f);
          i++;
          Node riceCake = new Node();
          unhealthy.createNode("Rice cake", i, 2f);
          i++;
          Node chocolate = new Node();
          unhealthy.createNode("Chocolate", i, -2f);
          i++;
          Node bacon = new Node();
          unhealthy.createNode("Bacon", i, -4f);
          i++;
          Node xmasPud = new Node();
          unhealthy.createNode("Christmas Pudding", i, -8f);
          i++;
          // Create all edges
          int n = 1;
          Edge food1 = new Edge();
          food1.createEdge("to healthy", i, -4.0f);
          food1.setStartNode(food);
          food1.setEndNode(healthy);
          n++;
          Edge food2 = new Edge();
          food2.createEdge("to neutral", i, 0);
          food2.setStartNode(food);
          food2.setEndNode(neutral);
          n++;
          Edge food3 = new Edge();
          food3.createEdge("to unhealthy", i, -4f);
          food3.setStartNode(food);
          food3.setEndNode(unhealthy);
          n++;
          Edge healthy1 = new Edge();
          healthy1.createEdge("to orange", i, 4f);
          healthy1.setStartNode(healthy);
          healthy1.setEndNode(orange);
          n++;
          Edge healthy2 = new Edge();
          healthy2.createEdge("to cabbage", i, 2f);
          healthy2.setStartNode(healthy);
          healthy2.setEndNode(cabbage);
          n++;
          Edge neutral1 = new Edge();
          neutral1.createEdge("to rice cake", i, 2f);
          neutral1.setStartNode(neutral);
          neutral1.setEndNode(riceCake);
          n++;
          Edge unhealthy1 = new Edge();
          unhealthy1.createEdge("to chocolate", i, -2f);
          unhealthy1.setStartNode(unhealthy);
          unhealthy1.setEndNode(chocolate);
          n++;
          Edge unhealthy2 = new Edge();
          unhealthy2.createEdge("to bacon", i, -4f);
          unhealthy2.setStartNode(unhealthy);
          unhealthy2.setEndNode(bacon);
          n++;
          Edge unhealthy3 = new Edge();
          unhealthy3.createEdge("to Christmas pudding", i, -8f);
          unhealthy3.setStartNode(unhealthy);
          unhealthy3.setEndNode(xmasPud);
          n++;
          // Assign edges to edgeList
          food.edgeList.add(food1);
          food.edgeList.add(food2);
          food.edgeList.add(food3);
          // Add node to nodeList
          nodeList.add(food);
          healthy.edgeList.add(healthy1);
          healthy.edgeList.add(healthy2);
          nodeList.add(healthy);
          neutral.edgeList.add(neutral1);
          nodeList.add(neutral);
          unhealthy.edgeList.add(unhealthy1);
          unhealthy.edgeList.add(unhealthy2);
          unhealthy.edgeList.add(unhealthy3);
          nodeList.add(unhealthy);
          // Now convert to arrays
          Node[] nodeArray = new Node; // Nodes
          nodeList.toArray(nodeArray);
          Edge[] edgeArray = new Edge[n]; // Edges
          food.edgeList.toArray(edgeArray);
          healthy.edgeList.toArray(edgeArray);
          unhealthy.edgeList.toArray(edgeArray);
          // Now turn it all into a graph
          createGraph("Food", 1, nodeArray, edgeArray, food); // doesn't work!
     public Graph createGraph(String name, int ID, Node[] nodes, Edge[] edges,
               Node root) {
          graphName = name;
          graphID = ID;
          graphNodes = nodes;
          graphEdges = edges;
          graphRoot = root;
          return null;
     public String getName() {
          return graphName;
     public Edge[] getEdges() {
          return graphEdges;
     public void addEdge(Edge e) {
     public Edge getEdge(String name, int ID) {
          return null;
     public void removeEdge(Edge e) {
     public Node[] getNodes() {
          return graphNodes;
     public void addNode(Node n) {
          nodeList.add(n);
     public Node getNode(String name, int ID) {
          int ni = nodeList.indexOf(name);
          Node rNode = nodeList.get(ni);
          return rNode;
     public void removeNode(Node n) {
          nodeList.remove(n);
     public void setRoot(Node n) {
          graphRoot = n;
     public Node getRoot() {
          return graphRoot;
     private String graphName;
     private int graphID;
     private Node[] graphNodes;
     private Edge[] graphEdges;
     private Node graphRoot;
     private static ArrayList<Node> nodeList = new ArrayList<Node>();
}The problem I have is that I don't know how to get around the fact that I'm making a static reference to the non-static method *createGraph*. I'd really appreciate your help. Thanks for your time!

GiselleT wrote:
public interface Edge {
public Edge createEdge(String name, int ID, float weight);
I want to kick your professor right in the grapes for this bit of idiocy. It's at the source of your problems.
This looks very fishy and very bad. I wouldn't expect an Edge to create another Edge. Likewise for Node and Graph. You might have static factory methods in these classes, but by defining it in the interfaces, these methods have to be non-static. This leads to such ridiculous code as you have like this:
Edge uselessEdge = new Edge();
Edge actualEdge = uselessEdge.createEdge("abc", 1, 2.34);It's not your fault that it's useless. That's the way you have to do it with that senseless requirement.
The problem I have is that I don't know how to get around the fact that I'm making a static reference to the non-static method createGraph.
Static reference in non-static context errors are always addressed the same way: Either make the member in question static (usually the wrong choice) or create an instance.
In this case, you need to do like you did with Edge, and create a useless dummy Graph whose only purpose is to create other Graphs:
Graph graph = uselessGraph();
Graph actualGraph = uselessGraph.createGraph(...);Then, inside the createGraph method, you'll create a Graph with new and do thatGraph.name = name; and so on for each of the parameters/members.
Really, though, this is just an awful, awful approach though. Are you sure your prof really requires Edge to have a non-static createEdge method, and so on?

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Daniel wrote:
> Can someone help with this CSS issue....
>
>
http://66.162.81.144/cms400min/default.aspx
>
> If you view the main page you will see that our
background is 2 shades of
> orange.. if you look at the line that divides those
colors to the right and
> left you wil notice that the line is higher
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background on top of the
> first one..its the only thing i can think of..
>
> the only place where the image is being referenced is in
this CSS style
>
> html, body
>
> {
>
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>
> margin-bottom:1px;
>
> text-align:center;
>
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>
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> is it because im applying the image to both the HTML and
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Answers on an postcard please.

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