/**
 *
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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 com.agfa.hap.sdo;

import java.util.Iterator;


/**
 * {@link SnapshotDefinition} that includes everything that is reachable
 * from the root object.
 * starting from the root object all child properties are visited
 * properties that are considered "proxy" by the datamapper are 
 * visited as proxies and will be serialized as sdo . (ie when using a HibernateDataMapper lazily retrieved objects that are "unitialized"
 * will be serialized as a sdo proxy) 
 * @author AMOCZ
 */
public class ReachableDefinition implements SnapshotDefinition {

	public <T> void visit(DataMapper<T> mapper, ObjectPropertyVisitor visitor, T root) throws Exception {
		Type type = mapper.getType(root);
		visitor.startDataObject(root, type);
		for (Property p : type.getProperties()) {
			try {
				if (p.isMany()) {
					Iterator<? extends T> it = mapper.getObjects(root, p);
					while (it.hasNext()) {
						visitChild(mapper, visitor, root, p, it.next());
					}
				} else {
					visitChild(mapper, visitor, root, p, mapper.getProperty(root, p));
				}
			} catch (PropertyNotAvailableException e) {
				// ok;
			}
		}
		visitor.endDataObject(root, type);
	}
	
	private <T> void visitChild(DataMapper<T> mapper, ObjectPropertyVisitor visitor, T parent, Property property, Object value) throws Exception {		
		if (value != null) {
			if (!property.getType().isDataType()) {
				T child = (T) value;
				if (mapper.isProxy(child)) {
					Type childType = mapper.getType(child);
					Object identity = mapper.getProperty(child, childType.getIdentityProperty());
					visitor.visitProxyProperty(parent, property, identity);
					return;
				}
			}
			boolean recurse = visitor.visitProperty(parent, property, value);
			if (recurse) {
				visit(mapper, visitor, (T) value);
			}
		}
	}
	
}