org.hibernate.engine.spi.EntityKey Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2013, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.engine.spi;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import org.hibernate.AssertionFailure;
import org.hibernate.internal.util.compare.EqualsHelper;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.pretty.MessageHelper;
/**
* Uniquely identifies of an entity instance in a particular Session by identifier.
* Note that it's only safe to be used within the scope of a Session: it doesn't consider for example the tenantId
* as part of the equality definition.
*
* Information used to determine uniqueness consists of the entity-name and the identifier value (see {@link #equals}).
*
* Performance considerations: lots of instances of this type are created at runtime. Make sure each one is as small as possible
* by storing just the essential needed.
*
* @author Gavin King
* @author Sanne Grinovero
*/
public final class EntityKey implements Serializable {
private final Serializable identifier;
private final int hashCode;
private final EntityPersister persister;
/**
* Construct a unique identifier for an entity class instance.
*
* NOTE : This signature has changed to accommodate both entity mode and multi-tenancy, both of which relate to
* the Session to which this key belongs. To help minimize the impact of these changes in the future, the
* {@link SessionImplementor#generateEntityKey} method was added to hide the session-specific changes.
*
* @param id The entity id
* @param persister The entity persister
*/
public EntityKey(Serializable id, EntityPersister persister) {
this.persister = persister;
if ( id == null ) {
throw new AssertionFailure( "null identifier" );
}
this.identifier = id;
this.hashCode = generateHashCode();
}
private int generateHashCode() {
int result = 17;
result = 37 * result + persister.getIdentifierType().getHashCode( identifier, persister.getFactory() );
return result;
}
public boolean isBatchLoadable() {
return persister.isBatchLoadable();
}
public Serializable getIdentifier() {
return identifier;
}
public String getEntityName() {
return persister.getEntityName();
}
@Override
public boolean equals(Object other) {
if ( this == other ) {
return true;
}
if ( other == null || EntityKey.class != other.getClass() ) {
return false;
}
final EntityKey otherKey = (EntityKey) other;
return samePersistentType( otherKey )
&& sameIdentifier( otherKey );
}
private boolean sameIdentifier(final EntityKey otherKey) {
return persister.getIdentifierType().isEqual( otherKey.identifier, this.identifier, persister.getFactory() );
}
private boolean samePersistentType(final EntityKey otherKey) {
if ( otherKey.persister == persister ) {
return true;
}
else {
return EqualsHelper.equals( otherKey.persister.getRootEntityName(), persister.getRootEntityName() );
}
}
@Override
public int hashCode() {
return hashCode;
}
@Override
public String toString() {
return "EntityKey" +
MessageHelper.infoString( this.persister, identifier, persister.getFactory() );
}
/**
* Custom serialization routine used during serialization of a
* Session/PersistenceContext for increased performance.
*
* @param oos The stream to which we should write the serial data.
*
* @throws IOException Thrown by Java I/O
*/
public void serialize(ObjectOutputStream oos) throws IOException {
oos.writeObject( identifier );
oos.writeObject( persister.getEntityName() );
}
/**
* Custom deserialization routine used during deserialization of a
* Session/PersistenceContext for increased performance.
*
* @param ois The stream from which to read the entry.
* @param sessionFactory The SessionFactory owning the Session being deserialized.
*
* @return The deserialized EntityEntry
*
* @throws IOException Thrown by Java I/O
* @throws ClassNotFoundException Thrown by Java I/O
*/
public static EntityKey deserialize(ObjectInputStream ois, SessionFactoryImplementor sessionFactory) throws IOException, ClassNotFoundException {
final Serializable id = (Serializable) ois.readObject();
final String entityName = (String) ois.readObject();
final EntityPersister entityPersister = sessionFactory.getEntityPersister( entityName );
return new EntityKey(id, entityPersister);
}
}