001// Licensed to the Apache Software Foundation (ASF) under one
002// or more contributor license agreements.  See the NOTICE file
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004// regarding copyright ownership.  The ASF licenses this file
005// to you under the Apache License, Version 2.0 (the
006// "License"); you may not use this file except in compliance
007// with the License.  You may obtain a copy of the License at
008//
009// http://www.apache.org/licenses/LICENSE-2.0
010//
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017
018package org.apache.tapestry5.services;
019
020/**
021 * Used by {@link ApplicationStateManager} and {@link ApplicationStatePersistenceStrategy} to create
022 * a Session State Object (SSO) on demand.
023 * <p>
024 * <em>NOTE: The term "Application" here is a hold-over from Tapestry 5.0, which used
025 * the @ApplicationState (deprecated and deleted) annotation, and called them "ASOs"
026 * (Application State Objects). This service would be better named "SessionStateCreator"
027 * (but renaming it would cause backwards compatibility issues).</em>
028 * 
029 * @param <T> the type of the created objects
030 */
031public interface ApplicationStateCreator<T>
032{
033    /**
034     * Create a new instance of a session state object.
035     */
036    T create();
037}