/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2011, 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.proxy;
import java.io.Serializable;
import org.hibernate.HibernateException;
import org.hibernate.LazyInitializationException;
import org.hibernate.SessionException;
import org.hibernate.TransientObjectException;
import org.hibernate.engine.spi.EntityKey;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.persister.entity.EntityPersister;
/**
* Convenience base class for lazy initialization handlers. Centralizes the basic plumbing of doing lazy
* initialization freeing subclasses to acts as essentially adapters to their intended entity mode and/or
* proxy generation strategy.
*
* @author Gavin King
*/
public abstract class AbstractLazyInitializer implements LazyInitializer {
private String entityName;
private Serializable id;
private Object target;
private boolean initialized;
private boolean readOnly;
private boolean unwrap;
private transient SessionImplementor session;
private Boolean readOnlyBeforeAttachedToSession;
/**
* For serialization from the non-pojo initializers (HHH-3309)
*/
protected AbstractLazyInitializer() {
}
/**
* Main constructor.
*
* @param entityName The name of the entity being proxied.
* @param id The identifier of the entity being proxied.
* @param session The session owning the proxy.
*/
protected AbstractLazyInitializer(String entityName, Serializable id, SessionImplementor session) {
this.entityName = entityName;
this.id = id;
// initialize other fields depending on session state
if ( session == null ) {
unsetSession();
}
else {
setSession( session );
}
}
@Override
public final String getEntityName() {
return entityName;
}
@Override
public final Serializable getIdentifier() {
return id;
}
@Override
public final void setIdentifier(Serializable id) {
this.id = id;
}
@Override
public final boolean isUninitialized() {
return !initialized;
}
@Override
public final SessionImplementor getSession() {
return session;
}
@Override
public final void setSession(SessionImplementor s) throws HibernateException {
if ( s != session ) {
// check for s == null first, since it is least expensive
if ( s == null ){
unsetSession();
}
else if ( isConnectedToSession() ) {
//TODO: perhaps this should be some other RuntimeException...
throw new HibernateException("illegally attempted to associate a proxy with two open Sessions");
}
else {
// s != null
session = s;
if ( readOnlyBeforeAttachedToSession == null ) {
// use the default read-only/modifiable setting
final EntityPersister persister = s.getFactory().getEntityPersister( entityName );
setReadOnly( s.getPersistenceContext().isDefaultReadOnly() || ! persister.isMutable() );
}
else {
// use the read-only/modifiable setting indicated during deserialization
setReadOnly( readOnlyBeforeAttachedToSession.booleanValue() );
readOnlyBeforeAttachedToSession = null;
}
}
}
}
private static EntityKey generateEntityKeyOrNull(Serializable id, SessionImplementor s, String entityName) {
if ( id == null || s == null || entityName == null ) {
return null;
}
return s.generateEntityKey( id, s.getFactory().getEntityPersister( entityName ) );
}
@Override
public final void unsetSession() {
session = null;
readOnly = false;
readOnlyBeforeAttachedToSession = null;
}
@Override
public final void initialize() throws HibernateException {
if (!initialized) {
if ( session==null ) {
throw new LazyInitializationException("could not initialize proxy - no Session");
}
else if ( !session.isOpen() ) {
throw new LazyInitializationException("could not initialize proxy - the owning Session was closed");
}
else if ( !session.isConnected() ) {
throw new LazyInitializationException("could not initialize proxy - the owning Session is disconnected");
}
else {
target = session.immediateLoad(entityName, id);
initialized = true;
checkTargetState();
}
}
else {
checkTargetState();
}
}
private void checkTargetState() {
if ( !unwrap ) {
if ( target == null ) {
getSession().getFactory().getEntityNotFoundDelegate().handleEntityNotFound( entityName, id );
}
}
}
/**
* Getter for property 'connectedToSession'.
*
* @return Value for property 'connectedToSession'.
*/
protected final boolean isConnectedToSession() {
return getProxyOrNull() != null;
}
private Object getProxyOrNull() {
final EntityKey entityKey = generateEntityKeyOrNull( getIdentifier(), session, getEntityName() );
if ( entityKey != null && session != null && session.isOpen() ) {
return session.getPersistenceContext().getProxy( entityKey );
}
return null;
}
@Override
public final Object getImplementation() {
initialize();
return target;
}
@Override
public final void setImplementation(Object target) {
this.target = target;
initialized = true;
}
@Override
public final Object getImplementation(SessionImplementor s) throws HibernateException {
final EntityKey entityKey = generateEntityKeyOrNull( getIdentifier(), s, getEntityName() );
return ( entityKey == null ? null : s.getPersistenceContext().getEntity( entityKey ) );
}
/**
* Getter for property 'target'.
* <p/>
* Same as {@link #getImplementation()} except that this method will not force initialization.
*
* @return Value for property 'target'.
*/
protected final Object getTarget() {
return target;
}
@Override
public final boolean isReadOnlySettingAvailable() {
return ( session != null && ! session.isClosed() );
}
private void errorIfReadOnlySettingNotAvailable() {
if ( session == null ) {
throw new TransientObjectException(
"Proxy is detached (i.e, session is null). The read-only/modifiable setting is only accessible when the proxy is associated with an open session." );
}
if ( session.isClosed() ) {
throw new SessionException(
"Session is closed. The read-only/modifiable setting is only accessible when the proxy is associated with an open session." );
}
}
@Override
public final boolean isReadOnly() {
errorIfReadOnlySettingNotAvailable();
return readOnly;
}
@Override
public final void setReadOnly(boolean readOnly) {
errorIfReadOnlySettingNotAvailable();
// only update if readOnly is different from current setting
if ( this.readOnly != readOnly ) {
final EntityPersister persister = session.getFactory().getEntityPersister( entityName );
if ( ! persister.isMutable() && ! readOnly ) {
throw new IllegalStateException( "cannot make proxies for immutable entities modifiable");
}
this.readOnly = readOnly;
if ( initialized ) {
EntityKey key = generateEntityKeyOrNull( getIdentifier(), session, getEntityName() );
if ( key != null && session.getPersistenceContext().containsEntity( key ) ) {
session.getPersistenceContext().setReadOnly( target, readOnly );
}
}
}
}
/**
* Get the read-only/modifiable setting that should be put in affect when it is
* attached to a session.
*
* This method should only be called during serialization when read-only/modifiable setting
* is not available (i.e., isReadOnlySettingAvailable() == false)
*
* @return null, if the default setting should be used;
* true, for read-only;
* false, for modifiable
* @throws IllegalStateException if isReadOnlySettingAvailable() == true
*/
protected final Boolean isReadOnlyBeforeAttachedToSession() {
if ( isReadOnlySettingAvailable() ) {
throw new IllegalStateException(
"Cannot call isReadOnlyBeforeAttachedToSession when isReadOnlySettingAvailable == true"
);
}
return readOnlyBeforeAttachedToSession;
}
/**
* Set the read-only/modifiable setting that should be put in affect when it is
* attached to a session.
*
* This method should only be called during deserialization, before associating
* the proxy with a session.
*
* @param readOnlyBeforeAttachedToSession, the read-only/modifiable setting to use when
* associated with a session; null indicates that the default should be used.
* @throws IllegalStateException if isReadOnlySettingAvailable() == true
*/
/* package-private */
final void setReadOnlyBeforeAttachedToSession(Boolean readOnlyBeforeAttachedToSession) {
if ( isReadOnlySettingAvailable() ) {
throw new IllegalStateException(
"Cannot call setReadOnlyBeforeAttachedToSession when isReadOnlySettingAvailable == true"
);
}
this.readOnlyBeforeAttachedToSession = readOnlyBeforeAttachedToSession;
}
@Override
public boolean isUnwrap() {
return unwrap;
}
@Override
public void setUnwrap(boolean unwrap) {
this.unwrap = unwrap;
}
}