# UpdateByIdListenerCollection.java

    package org.codefilarete.stalactite.engine.listener;

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

    /**
     * @author Guillaume Mary
     */
    public class UpdateByIdListenerCollection<C> implements UpdateByIdListener<C> {

    	private final List<UpdateByIdListener<C>> updateByIdListeners = new ArrayList<>();

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

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

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

    	public void add(UpdateByIdListener<C> updateByIdListener) {
    		this.updateByIdListeners.add(updateByIdListener);
    	}

    	/**
    	 * 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 updateByIdListener the target listener on which the one of current instance must be moved to.
    	 */
    	public void moveTo(UpdateByIdListenerCollection<C> updateByIdListener) {
    		updateByIdListener.updateByIdListeners.addAll(this.updateByIdListeners);
    		this.updateByIdListeners.clear();
    	}

    }