/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.deltaspike.data.api.mapping;
import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.List;
import javax.inject.Inject;
import org.apache.deltaspike.data.spi.QueryInvocationContext;
/**
* A base mapper to map from Dto to Entity and vice versa. This should be sufficient
* for most mapping cases and simplify the implementation of a mapper.
*
* @param <Entity> The Entity type.
* @param <Dto> The Dto type.
*/
public abstract class SimpleQueryInOutMapperBase<Entity, Dto> implements QueryInOutMapper<Entity>
{
@Inject
private QueryInvocationContext context;
/**
* Return the primary key of the Entity corresponding to the Dto. If this is a new
* Entity, return {@code null}.
* @param dto The Dto to map to an Entity.
* @return The Entity primary key, or {@code null} for a new Entity.
*/
protected abstract Object getPrimaryKey(Dto dto);
protected abstract Dto toDto(Entity entity);
/**
* Map a Dto to an Entity. In case the Dto contains a valid primary key,
* the Entity will be retrieved first and used as method parameter. Otherwise
* Entity is a unmanaged new instance.
*
* @param entity Either a managed Entity looked up by the primary key,
* or a new Entity instance.
* @param dto The Dto to map.
* @return Mapped Entity.
*/
protected abstract Entity toEntity(Entity entity, Dto dto);
@Override
public Object mapResult(final Entity result)
{
if (result == null)
{
return null;
}
return toDto(result);
}
@Override
public Object mapResultList(final List<Entity> result)
{
if (result != null)
{
final List<Object> mapped = new ArrayList<Object>(result.size());
for (final Entity a : result)
{
mapped.add(mapResult(a));
}
return mapped;
}
return new ArrayList<Object>();
}
@Override
public boolean mapsParameter(final Object parameter)
{
if (parameter == null)
{
return false;
}
final String name = parameter.getClass().getName();
return Object.class.isInstance(parameter) && !(name.startsWith("java.") || name.startsWith("javax."));
}
@Override
public Object mapParameter(final Object parameter)
{
Dto dto = (Dto) parameter;
Object primaryKey = getPrimaryKey(dto);
if (primaryKey != null)
{
Entity entity = findEntity(primaryKey);
return toEntity(entity, dto);
}
return toEntity(newEntity(), dto);
}
@SuppressWarnings("unchecked")
protected Entity newEntity()
{
try
{
Class<?> entityClass = context.getEntityClass();
Constructor<?> constructor = entityClass.getDeclaredConstructor();
constructor.setAccessible(true);
return (Entity) constructor.newInstance();
}
catch (Exception e)
{
throw new RuntimeException("Failed instantiating new Entity", e);
}
}
@SuppressWarnings("unchecked")
protected Entity findEntity(Object primaryKey)
{
return (Entity) context.getEntityManager().find(context.getEntityClass(), primaryKey);
}
}