package cz.cuni.amis.pogamut.base.agent.navigation.impl;
   
   import java.util.List;
   import java.util.concurrent.TimeUnit;
   
   import cz.cuni.amis.pogamut.base.agent.navigation.IPathFuture;
   import cz.cuni.amis.utils.SyncLazy;
   import cz.cuni.amis.utils.future.FutureStatus;
   import cz.cuni.amis.utils.future.IFutureListener;
  import cz.cuni.amis.utils.listener.Listeners;
  
  /**
   * Serves as a {@link IPathFuture} that contains pre-set result, i.e., you do not need the future, you just want to pass down
   * some value...
   * 
   * @author Jimmy
   *
   * @param <PATH_ELEMENT>
   */
  public class PrecomputedPathFuture<PATH_ELEMENT> implements IPathFuture<PATH_ELEMENT> {
  
  	private PATH_ELEMENT pathFrom;
  	private PATH_ELEMENT pathTo;
  	private List<PATH_ELEMENT> result;
  	private SyncLazy<Listeners<IFutureListener>> listeners = new SyncLazy<Listeners<IFutureListener>>() {
  		@Override
  		protected Listeners<IFutureListener> create() {
  			return new Listeners<IFutureListener>();
  		}
  	};
  
  	public PrecomputedPathFuture(PATH_ELEMENT from, PATH_ELEMENT to, List<PATH_ELEMENT> path) {
  		this.pathFrom = from;
  		this.pathTo = to;
  		this.result = path;
  	}
  
  	@Override
  	public PATH_ELEMENT getPathFrom() {
  		return pathFrom;
  	}
  
  	@Override
  	public PATH_ELEMENT getPathTo() {
  		return pathTo;
  	}
  	
  	@Override
  	public void addFutureListener(IFutureListener<List<PATH_ELEMENT>> listener) {
  		listeners.get().addWeakListener(listener);
  	}
  	
  	@Override
  	public void removeFutureListener(IFutureListener<List<PATH_ELEMENT>> listener) {
  		listeners.get().removeListener(listener);
  	}
  
  	@Override
  	public List<PATH_ELEMENT> get() {
  		return result;
  	}
  
  	@Override
  	public List<PATH_ELEMENT> get(long timeout, TimeUnit unit) {
  		return result;
  	}
  
  	@Override
  	public FutureStatus getStatus() {
  		return FutureStatus.FUTURE_IS_READY;
  	}
  
  	@Override
  	public boolean isListening(IFutureListener<List<PATH_ELEMENT>> listener) {
  		return listeners.get().isListening(listener);
  	}
  
  	@Override
  	public boolean cancel(boolean mayInterruptIfRunning) {
  		return false;
  	}
  
  	@Override
  	public boolean isCancelled() {
  		return false;
  	}
  
  	@Override
  	public boolean isDone() {
  		return true;
  	}
  
  }