net.sf.javagimmicks.collections8.event.ObservableEventCollection Maven / Gradle / Ivy

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package net.sf.javagimmicks.collections8.event;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import net.sf.javagimmicks.collections8.event.CollectionEvent.Type;
import net.sf.javagimmicks.event.EventListener;
import net.sf.javagimmicks.event.Observable;
import net.sf.javagimmicks.event.ObservableBase;

/**
 * A {@link Collection} decorator that serves as an {@link Observable} for
 * {@link CollectionEvent}s.
 */
public class ObservableEventCollection extends AbstractEventCollection implements
      Observable>
{
   private static final long serialVersionUID = -4055919694275882002L;

   protected final ObservableBase> _helper = new ObservableBase>();

   /**
    * Wraps a new {@link ObservableEventCollection} around a given
    * {@link Collection}.
    * 
    * @param decorated
    *           the {@link Collection} to wrap around
    */
   public ObservableEventCollection(final Collection decorated)
   {
      super(decorated);
   }

   @Override
   public >> void addEventListener(final L listener)
   {
      _helper.addEventListener(listener);
   }

   @Override
   public >> void removeEventListener(final L listener)
   {
      _helper.removeEventListener(listener);
   }

   @Override
   protected void fireElementsAdded(final Collection elements)
   {
      _helper.fireEvent(new CollectionEventImpl(Type.ADDED, Collections.unmodifiableCollection(new ArrayList(
            elements))));
   }

   @Override
   protected void fireElementRemoved(final E element)
   {
      _helper.fireEvent(new CollectionEventImpl(Type.REMOVED, Collections.singleton(element)));
   }

   private class CollectionEventImpl implements CollectionEvent
   {
      protected final Type _type;
      protected final Collection _elements;

      public CollectionEventImpl(final Type type,
            final Collection elements)
      {
         _type = type;
         _elements = elements;
      }

      @Override
      public Type getType()
      {
         return _type;
      }

      @Override
      public Collection getElements()
      {
         return _elements;
      }

      @Override
      public ObservableEventCollection getSource()
      {
         return ObservableEventCollection.this;
      }
   }
}