title: Simple example of Guava ValueGraph
body: <p>I'm looking for simple example of Guava ValueGraph. Something like:</p>
  
  <pre><code>class GraphNode {
    String name;
    String value;
    // Do I need to override equals &amp; hashcode methods here??
  
  }
  
  class GraphUser {
    public ValueGraph&lt;GraphNode,Double&gt; createGraph(){
      ValueGraph&lt;GraphNode,Double&gt; graph = ValueGraphBuilder.directed.build();
      // How do I add the nodes to graph??
      // How do I add the edges to graph?
    }
  }
  </code></pre>
  
  <ol>
  <li>How do I create graph with custom object as node?</li>
  <li>How do I add nodes &amp; edges to graph?</li>
  <li>Do I have to override the equals &amp; hashCode methods in the custom node class?</li>
  </ol>
  
  <p>A simple example would be very helpful.</p>