Making a template

Question

I want to make a template for a kind of class. But I don't just want to specify the interface--I want to control 80% of the action of the class. Specifically I want to
1. Specify an abstract constructor or something like it. The best I've come up with on this so far is making the constructor always throw an exception unless it's overridden.
2. Specify some static final fields. My best effort on this so far is making some abstract functions that are intended to return only constants, but I have no way to enforce that they return only constants and it seems like a bad solution.
3. I'd like to have an abstract nested class within this template, with an abstract function inside the nested class to be implemented by concrete subclasses of the outer class. But when I try to do this, it (eclipse) doesn't give me an error if I don't implement the nested class when I make a concrete subclass.
What would be best is if I could make it so Eclipse says a concrete subclass has a syntax error until all the things I want implemented about this class, actually are implemented.

Answer 1

Being more specific, this is the class I have so far:
package machines;
import java.util.Vector;
* Provides the format for a single tile on the ground
public abstract class Tile
     /**Neighbors of the Tile.  Subclasses of Tile should
      * define final ints that name the indices of this vector
      * from 0 to NEIGHBORS - 1, e.g. NORTH SOUTH EAST WEST
     Vector<Tile> neighbors;
     private boolean initialized = false;
     /** Specified number of neighbors*/
     private Vector<Ant> antsOnTile;
     private Vector<Message> messageSet;
     public Tile(){}
      * @return the number of neighbors this tile should have
     protected abstract int numNeighbors();
     public void intializeTile(Vector<Tile> neighbors) throws TileException
          if(neighbors == null || neighbors.size() != numNeighbors() || neighbors.indexOf(null) >= 0 || initialized == true)
               throw new TileException();
          this.neighbors = neighbors;
          initialized = true;
     public void receiveAnt(Ant a)
          antsOnTile.add(a);
     public void sendAnt(int neighbor) throws TileException
          if(neighbor > numNeighbors() || neighbor < 0)
               throw new TileException();
          Ant a = antsOnTile.remove(0);
          if(a == null)
               throw new TileException();
          neighbors.get(neighbor).receiveAnt(a);
     public void receiveMessage(Message a)
          messageSet.add(a);
     public void sendMessage(int neighbor, Message m) throws TileException
          if(neighbor > numNeighbors() || neighbor < 0)
               throw new TileException();
          neighbors.get(neighbor).receiveMessage(m);
     public class TileException extends Exception
          static final long SerialVersionUID = 2L;
     public class Message
          String name;
          public Message(String name)
               this.name = name;
     public abstract class FiniteStateMachine
          class State
               String name = new String();
               public String toString()
                    return name;
          /** the output of a step of the FSM */
          class Output
               State q;
               Vector<Message> m;
               // ants contains true at index i iff this fsm is sending
               // an ant to neighbor i this step
               Vector<Boolean> ants;
          final Vector<State> Q;
          State q;
           * Always throws a tile exception
           * a subclass should override this to specify
           * the set of states Q and a start state
           * @throws TileException
          public FiniteStateMachine() throws TileException
               Q = null;
               q = null;
               throw new TileException();
               // this must be filled in by the user
               // Initialize all states
               // Initialize the start state
           * The next state function for the FSM
           * @param qi the current state
           * @param m the current queued messages
           * @return an Output object containing the new state and new messages
          abstract Output lambda(State qi, Vector<Message> m);
          public void update() throws TileException
               if(messageSet == null || messageSet.size() != numNeighbors() || messageSet.indexOf(null) >= 0)
                    throw new TileException();
               Output o = lambda(q, messageSet);
               messageSet = null;
               q = o.q;
               if(o.m == null || o.m.size() != numNeighbors() || o.m.indexOf(null) >= 0)
                    throw new TileException();
               if(o.ants == null || o.ants.size() != numNeighbors() || o.ants.indexOf(null) >= 0)
                    throw new TileException();
               for(int i = 0; i < numNeighbors(); i++)
                    sendMessage(i, o.m.get(i));
                    if(o.ants.get(i).booleanValue())
                         sendAnt(i);
}I want someone subclassing it to have to fill in Tile.FiniteStateMachine.lambda(), specify a number of neighbors (optimally a static final int, but as you see what I have is a function), and specify a constructor for FiniteStateMachine that fills in Q and initializes q to a member of Q. Everything else I want to have fixed, and if they don't do those three things I want it to show an error.