/* This file is part of the db4o object database http://www.db4o.com
Copyright (C) 2004 - 2011 Versant Corporation http://www.versant.com
db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.
db4o 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 General Public License
for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see http://www.gnu.org/licenses/. */
package com.db4o.internal;
import com.db4o.foundation.*;
import com.db4o.typehandlers.*;
/**
* @exclude
*/
public class HandlerVersionRegistry {
private final HandlerRegistry _registry;
private final Hashtable4 _versions = new Hashtable4();
public HandlerVersionRegistry(HandlerRegistry registry){
_registry = registry;
}
public void put(TypeHandler4 handler, int version, TypeHandler4 replacement) {
_versions.put(new HandlerVersionKey(handler, version), replacement);
}
public TypeHandler4 correctHandlerVersion(final TypeHandler4 originalHandler, final int version) {
if(version >= HandlerRegistry.HANDLER_VERSION){
return originalHandler;
}
if(originalHandler == null){
return null; // HandlerVersionKey with null key will throw NPE.
}
TypeHandler4 replacement = (TypeHandler4) _versions.get(new HandlerVersionKey(genericTemplate(originalHandler), version));
if(replacement == null){
return correctHandlerVersion(originalHandler, version + 1);
}
if(replacement instanceof VersionedTypeHandler){
return (TypeHandler4) ((VersionedTypeHandler)replacement).deepClone(new TypeHandlerCloneContext(_registry, originalHandler, version));
};
return replacement;
}
private TypeHandler4 genericTemplate(final TypeHandler4 handler) {
if (handler instanceof VersionedTypeHandler){
return ((VersionedTypeHandler)handler).unversionedTemplate();
}
return handler;
}
private class HandlerVersionKey {
private final TypeHandler4 _handler;
private final int _version;
public HandlerVersionKey(TypeHandler4 handler, int version){
_handler = handler;
_version = version;
}
public int hashCode() {
return _handler.hashCode() + _version * 4271;
}
public boolean equals(Object obj) {
HandlerVersionKey other = (HandlerVersionKey) obj;
return _handler.equals(other._handler) && _version == other._version;
}
}
}