org.simpleframework.xml.core.ObjectFactory Maven / Gradle / Ivy
/*
* ObjectFactory.java July 2006
*
* Copyright (C) 2006, Niall Gallagher
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation.
*
* This library 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 library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*/
package org.simpleframework.xml.core;
import org.simpleframework.xml.strategy.Value;
import org.simpleframework.xml.stream.InputNode;
/**
* The ObjectFactory is the most basic factory. This will
* basically check to see if there is an override type within the XML
* node provided, if there is then that is instantiated, otherwise the
* field type is instantiated. Any type created must have a default
* no argument constructor. If the override type is an abstract class
* or an interface then this factory throws an exception.
*
* @author Niall Gallagher
*/
class ObjectFactory extends PrimitiveFactory {
/**
* Constructor for the ObjectFactory class. This is
* given the field class that this should create object instances
* of. If the field type is abstract then the XML node must have
* sufficient information for the Strategy object to
* resolve the implementation class to be instantiated.
*
* @param context the contextual object used by the persister
* @param field this is the field type of the object
*/
public ObjectFactory(Context context, Class field) {
super(context, field);
}
/**
* This method will instantiate an object of the field type, or if
* the Strategy object can resolve a class from the
* XML element then this is used instead. If the resulting type is
* abstract or an interface then this method throws an exception.
*
* @param node this is the node to check for the override
*
* @return this returns an instance of the resulting type
*/
@Override
public Instance getInstance(InputNode node) throws Exception {
Value type = getOverride(node);
if(type == null) {
if(!isInstantiable(field)) {
throw new InstantiationException("Cannot instantiate %s", field);
}
return context.getInstance(field);
}
return new ObjectInstance(context, type);
}
}