title: Priority queue for HashMaps
body: <p>I have a hash map of a string and a vertex which is a class.</p>
  
  <p>I want to create a priority queue for an attribute distance of vertex class... How should I do it...</p>
  
  <pre><code>private final PriorityQueue Nodes ;
  private HashMap&lt;String,Vertex&gt; c ;
  </code></pre>
  
  <p>I have to create a priority queue on all the members of the hashmap c according to the vertex.distance value.....</p>
  
  <p>Please tell how should i do that as I always get compilation error on whatever I am trying....</p>