ConcreteCollectionToCollectionWrapperModel.java

package fr.openwide.core.wicket.markup.html.model;

import java.util.Collection;

import org.apache.wicket.model.IModel;

import com.google.common.base.Supplier;

/**
 * A wrapper allowing to handle an IModel<? extends Collection<T>> as if it were an IModel<Collection<T>>, both when reading it and writing to it.
 *
 * @param <T> The collection's element type
 * @param <C> The underlying collection type
 */
public class ConcreteCollectionToCollectionWrapperModel<T, C extends Collection<T>> implements IModel<Collection<T>> {

	private static final long serialVersionUID = -6342356257002249205L;
	
	private final IModel<C> concreteCollectionModel;
	
	private final Supplier<? extends C> concreteCollectionSupplier;

	public ConcreteCollectionToCollectionWrapperModel(IModel<C> concreteCollectionModel, Supplier<? extends C> concreteCollectionSupplier) {
		this.concreteCollectionModel = concreteCollectionModel;
		this.concreteCollectionSupplier = concreteCollectionSupplier;
	}

	@Override
	public Collection<T> getObject() {
		return concreteCollectionModel.getObject();
	}

	@Override
	public void setObject(Collection<T> object) {
		C concreteCollection;
		if (object == null) {
			concreteCollection = null;
		} else {
			concreteCollection = concreteCollectionSupplier.get();
			concreteCollection.addAll(object);
		}
		concreteCollectionModel.setObject(concreteCollection);
	}

	@Override
	public void detach() {
		concreteCollectionModel.detach();
	}

}