    001    // Copyright 2011 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    // http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.internal.jpa;
    016
    017    import org.apache.tapestry5.ValueEncoder;
    018    import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    019    import org.apache.tapestry5.ioc.services.PropertyAccess;
    020    import org.apache.tapestry5.ioc.services.PropertyAdapter;
    021    import org.apache.tapestry5.ioc.services.TypeCoercer;
    022    import org.apache.tapestry5.jpa.EntityManagerManager;
    023    import org.slf4j.Logger;
    024
    025    import javax.persistence.EntityManager;
    026    import javax.persistence.metamodel.EntityType;
    027    import javax.persistence.metamodel.SingularAttribute;
    028    import javax.persistence.metamodel.Type;
    029
    030    public class JpaValueEncoder<E> implements ValueEncoder<E>
    031    {
    032        private final EntityType<E> entity;
    033        private final EntityManagerManager entityManagerManager;
    034        private final String persistenceUnitName;
    035        private final TypeCoercer typeCoercer;
    036        private final Logger logger;
    037        private final String idPropertyName;
    038        private final PropertyAdapter propertyAdapter;
    039
    040        public JpaValueEncoder(final EntityType<E> entity,
    041                final EntityManagerManager entityManagerManager, final String persistenceUnitName,
    042                final PropertyAccess propertyAccess, final TypeCoercer typeCoercer, final Logger logger)
    043        {
    044            super();
    045            this.entity = entity;
    046            this.entityManagerManager = entityManagerManager;
    047            this.persistenceUnitName = persistenceUnitName;
    048            this.typeCoercer = typeCoercer;
    049            this.logger = logger;
    050
    051            final Type<?> idType = this.entity.getIdType();
    052
    053            final SingularAttribute<? super E, ?> idAttribute = this.entity.getId(idType.getJavaType());
    054
    055            idPropertyName = idAttribute.getName();
    056
    057            propertyAdapter = propertyAccess.getAdapter(entity.getJavaType()).getPropertyAdapter(
    058                    idPropertyName);
    059
    060        }
    061
    062        /**
    063         * {@inheritDoc}
    064         */
    065        public String toClient(final E value)
    066        {
    067            if (value == null)
    068                return null;
    069
    070            final Object id = propertyAdapter.get(value);
    071
    072            if (id == null)
    073            {
    074                return null;
    075            }
    076
    077            return typeCoercer.coerce(id, String.class);
    078        }
    079
    080        /**
    081         * {@inheritDoc}
    082         */
    083        public E toValue(final String clientValue)
    084        {
    085            if (InternalUtils.isBlank(clientValue))
    086                return null;
    087
    088            Object id = null;
    089            final Class<E> entityClass = entity.getJavaType();
    090
    091            try
    092            {
    093
    094                id = typeCoercer.coerce(clientValue, propertyAdapter.getType());
    095            }
    096            catch (final Exception ex)
    097            {
    098                throw new RuntimeException(String.format(
    099                        "Exception converting '%s' to instance of %s (id type for entity %s): %s",
    100                        clientValue, propertyAdapter.getType().getName(), entityClass.getName(),
    101                        InternalUtils.toMessage(ex)), ex);
    102            }
    103
    104            final EntityManager em = entityManagerManager.getEntityManager(persistenceUnitName);
    105
    106            final E result = em.find(entityClass, id);
    107
    108            if (result == null)
    109            {
    110                // We don't identify the entity type in the message because the logger is based on the
    111                // entity type.
    112                logger.error(String.format(
    113                        "Unable to convert client value '%s' into an entity instance.", clientValue));
    114            }
    115
    116            return result;
    117        }
    118    }