/**
 *
 *  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.io.Serializable;
import java.util.List;


/**
 * Collection of structured data at a given moment in time. 
 * You can think of this as a set of name-value pairs
 * where the names correspond to various {@link Property} instances.
 * The actual content (i.e. which properties are contained) has been defined based on 
 * a {@link SnapshotDefinition}.
 * <br />
 * The difference with a DataGraph is that a Snapshot contains the state of a
 * set of dataobjects at a certain moment in time. As such it is immutable.
 * Another difference is that is defines its content based on a definition as opposed
 * to the datagraph that uses the containment relation 
 * defined by sdo ({@see {@link Property#isContainment()}).
 * <br />
 * The data can be extracted either as a set of {@link ProxyDataObject} instances.
 * The data can also be returned as a set of objects (POJOs). The latter case assumes 
 * appropriate classes can be
 * found that correspond to the different {@link Type}s that are used.
 * <br />
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future hap.SDO releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of hap.sdo.
 * 
 * @author AMOCZ
 * @see DataAccessService
 * @see DataMapper
 */
public interface Snapshot extends Serializable {

	/**
	 * Extracts the objects from the snapshots
	 * @param factory
	 * @return A list containing new objects with appropriate properties filled in.
	 */
	<T> List<T> extract(DataMapper<T> mapper);
	
}