# DeleteListenerCollection.java

    package org.codefilarete.stalactite.engine.listener;

    import java.util.ArrayList;
    import java.util.List;

    /**
     * @author Guillaume Mary
     */
    public class DeleteListenerCollection<C> implements DeleteListener<C> {

    	private final List<DeleteListener<C>> deleteListeners = new ArrayList<>();

    	@Override
    	public void beforeDelete(Iterable<? extends C> entities) {
    		deleteListeners.forEach(listener -> listener.beforeDelete(entities));
    	}

    	@Override
    	public void afterDelete(Iterable<? extends C> entities) {
    		deleteListeners.forEach(listener -> listener.afterDelete(entities));
    	}

    	@Override
    	public void onDeleteError(Iterable<? extends C> entities, RuntimeException runtimeException) {
    		deleteListeners.forEach(listener -> listener.onDeleteError(entities, runtimeException));
    	}

    	public void add(DeleteListener<? extends C> deleteListener) {
    		this.deleteListeners.add((DeleteListener<C>) deleteListener);
    	}

    	/**
    	 * Move internal listeners to given instance.
    	 * Useful to aggregate listeners into a single instance.
    	 * Please note that as this method is named "move" it means that listeners of current instance will be cleared.
    	 *
    	 * @param deleteListener the target listener on which the one of current instance must be moved to.
    	 */
    	public void moveTo(DeleteListenerCollection<C> deleteListener) {
    		deleteListener.deleteListeners.addAll(this.deleteListeners);
    		this.deleteListeners.clear();
    	}

    }