package bluej.utility.javafx.binding;

import java.util.IdentityHashMap;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import bluej.utility.javafx.JavaFXUtil;
import bluej.utility.javafx.MultiListener;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;




| This class is useful when you want to bind one (observable) list to some function of another observable list
| but you need to not only listen to changes in that list, but also further lists inside it.
|
public abstract class DeepListBinding<DEST>{    
   private final ObservableList<DEST> dest;
   
   private final MultiListener<ObservableList<?>> multiListener;
    
   
   public DeepListBinding(ObservableList<DEST> dest)
   {        
      this.dest = dest;
      final ListChangeListener<Object> listener = c -> update();
       
      this.multiListener = new MultiListener<>(l -> { l.addListener(listener); return () -> l.removeListener(listener);
      });
   }
    
   
public void startListening()
   {
   update();     
   }

   
protected abstract Stream> getListenTargets();
    
   
protected abstract Stream calculateValues();

   
protected void update()
   {        
   
   multiListener.listenOnlyTo(getListenTargets());
        
       
   
   dest.setAll(calculateValues().collect(Collectors.toList()));     
   } 
}