Java tutorial
/* * Copyright (C) 2009-2011 Open Wide * Contact: contact@openwide.fr * * 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 fr.openwide.core.wicket.more.model; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import org.apache.commons.lang3.builder.EqualsBuilder; import org.apache.commons.lang3.builder.HashCodeBuilder; import org.apache.wicket.injection.Injector; import org.apache.wicket.model.LoadableDetachableModel; import org.apache.wicket.spring.injection.annot.SpringBean; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.base.Function; import fr.openwide.core.jpa.business.generic.model.GenericEntity; import fr.openwide.core.jpa.business.generic.model.GenericEntityReference; import fr.openwide.core.jpa.business.generic.service.IEntityService; import fr.openwide.core.jpa.util.HibernateUtils; import fr.openwide.core.wicket.more.util.model.LoadableDetachableModelExtendedDebugInformation; public class GenericEntityModel<K extends Serializable & Comparable<K>, E extends GenericEntity<K, ?>> extends LoadableDetachableModel<E> { private static final long serialVersionUID = 1L; private static final Logger LOGGER = LoggerFactory.getLogger(GenericEntityModel.class); private static final boolean EXTENDED_DEBUG_INFO; static { EXTENDED_DEBUG_INFO = LOGGER.isDebugEnabled(); if (EXTENDED_DEBUG_INFO) { LOGGER.warn("Extended debug info for GenericEntityModel is enabled." + " This may cause a significant performance hit."); } } @SuppressWarnings("unchecked") // SerializableModelFactory works for any T extending GenericEntity<?, ?> public static <E extends GenericEntity<?, ?>> Function<E, GenericEntityModel<?, E>> factory() { return (Function<E, GenericEntityModel<?, E>>) (Object) Factory.INSTANCE; } @SuppressWarnings({ "rawtypes", "unchecked" }) // SerializableModelFactory works for any T extending Serializable private enum Factory implements Function<GenericEntity, GenericEntityModel> { INSTANCE; @Override public GenericEntityModel apply(GenericEntity input) { return new GenericEntityModel(input); } } @SpringBean private IEntityService entityService; private transient boolean attached = false; private transient LoadableDetachableModelExtendedDebugInformation extendedDebugInformation; private GenericEntityReference<K, E> persistedEntityReference; /** * L'objectif est ici de stocker les entits qui n'ont pas encore t persistes en base (typiquement, quand * on fait la cration). */ private E notYetPersistedEntity; public static <K extends Serializable & Comparable<K>, E extends GenericEntity<K, ?>> GenericEntityModel<K, E> of( E entity) { return new GenericEntityModel<K, E>(entity); } @SuppressWarnings({ "unchecked", "rawtypes" }) public static <E extends GenericEntity<?, ?>> GenericEntityModel<?, E> ofUnknownIdType(E entity) { return (GenericEntityModel<?, E>) new GenericEntityModel(entity); } /** * Construit un GenericEntityModel dont l'objet est <code>null</code> et qui n'est pas attach. */ public GenericEntityModel() { Injector.get().inject(this); if (EXTENDED_DEBUG_INFO) { this.extendedDebugInformation = new LoadableDetachableModelExtendedDebugInformation(); } else { this.extendedDebugInformation = null; } } public GenericEntityModel(E entity) { this(); setObject(entity); } @Override protected E load() { E result = null; if (persistedEntityReference != null) { result = HibernateUtils.unwrap(entityService.getEntity(persistedEntityReference)); } else { result = notYetPersistedEntity; } attached = true; if (EXTENDED_DEBUG_INFO) { extendedDebugInformation.onAttach(); } return result; } @Override public void setObject(E entity) { E persistentObject = HibernateUtils.unwrap(entity); super.setObject(persistentObject); attached = true; if (EXTENDED_DEBUG_INFO) { extendedDebugInformation.onAttach(); } updateSerializableData(); // Useful to keep equals() and getId() up-to-date and for compatibility with old applications } protected K getId() { return persistedEntityReference != null ? persistedEntityReference.getId() : null; } @Override public void detach() { if (EXTENDED_DEBUG_INFO) { extendedDebugInformation.onDetach(); } if (!attached) { fixSerializableData(); return; } updateSerializableData(); super.detach(); attached = false; } /** * Updates the serializable data (id, clazz, notYetPersistedEntity) according to the attached object's value. * <p>Only called when the model is attached. */ private void updateSerializableData() { E entity = super.getObject(); if (entity != null) { if (entity.getId() != null) { persistedEntityReference = GenericEntityReference.of(entity); notYetPersistedEntity = null; } else { persistedEntityReference = null; notYetPersistedEntity = entity; } } else { persistedEntityReference = null; notYetPersistedEntity = null; } } /** * If the entity has been persisted since this model has been detached, then fix the serializable data * (this may happen if two models reference the same non-persisted entity, for instance) */ private void fixSerializableData() { if (notYetPersistedEntity != null && notYetPersistedEntity.getId() != null) { persistedEntityReference = GenericEntityReference.of(notYetPersistedEntity); notYetPersistedEntity = null; } } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (obj == this) { return true; } if (!(obj instanceof GenericEntityModel)) { return false; } GenericEntityModel<?, ?> other = (GenericEntityModel<?, ?>) obj; return new EqualsBuilder().append(persistedEntityReference, other.persistedEntityReference) .append(notYetPersistedEntity, other.notYetPersistedEntity).isEquals(); } @Override public int hashCode() { return new HashCodeBuilder().append(persistedEntityReference).append(notYetPersistedEntity).toHashCode(); } private void readObject(ObjectInputStream in) throws ClassNotFoundException, IOException { in.defaultReadObject(); if (EXTENDED_DEBUG_INFO) { this.extendedDebugInformation = new LoadableDetachableModelExtendedDebugInformation(); } } private void writeObject(ObjectOutputStream out) throws IOException { if (attached) { LOGGER.warn( "Serializing an attached GenericEntityModel with persistedEntityReference={} and notYetPersistedEntity={}", persistedEntityReference, notYetPersistedEntity); if (EXTENDED_DEBUG_INFO) { LOGGER.debug("StackTrace from the latest attach (setObject() or load()): \n{}", extendedDebugInformation.getLatestAttachInformation()); } } out.defaultWriteObject(); } }