/*
* Copyright 2011 Marc Grue.
* Copyright (c) 2013, Niclas Hedhman. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.qi4j.sample.dcicargo.sample_b.infrastructure.model;
import org.apache.wicket.model.IModel;
import org.qi4j.api.entity.EntityComposite;
import org.qi4j.api.entity.EntityReference;
import org.qi4j.api.unitofwork.NoSuchEntityException;
import org.qi4j.sample.dcicargo.sample_b.infrastructure.conversion.DTO;
/**
* EntityModel
*
* A Wicket Model that bridges to our Qi4j data store.
*
* In Wicket we need to be able to pass around serializable data that can be "detachable".
* Qi4j entities are therefore lazy loaded with a class and identity through our UnitOfWork
* and then converted to a DTO ValueComposite.
*/
public class EntityModel<T extends DTO, U extends EntityComposite>
extends ReadOnlyModel<T>
{
private Class<U> entityClass;
private String identity;
private Class<T> dtoClass;
private transient T dtoComposite;
public EntityModel( Class<U> entityClass, String identity, Class<T> dtoClass )
{
this.entityClass = entityClass;
this.identity = identity;
this.dtoClass = dtoClass;
}
public static <T extends DTO, U extends EntityComposite> IModel<T> of(
Class<U> entityClass, String identity, Class<T> dtoClass
)
{
return new EntityModel<T, U>( entityClass, identity, dtoClass );
}
public T getObject()
{
if( dtoComposite == null && identity != null )
{
dtoComposite = valueConverter.convert( dtoClass, loadEntity() );
}
return dtoComposite;
}
public void detach()
{
dtoComposite = null;
}
private U loadEntity()
{
U entity = module.currentUnitOfWork().get( entityClass, identity );
if( entity == null )
{
throw new NoSuchEntityException( EntityReference.parseEntityReference( identity ), entityClass );
}
return entity;
}
}