// Copyright 2007, 2008 The Apache Software Foundation

 //

 // Licensed 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 org.apache.tapestry5.annotations;

 import java.lang.annotation.Documented;

 import static java.lang.annotation.ElementType.FIELD;

 import java.lang.annotation.Retention;

 import static java.lang.annotation.RetentionPolicy.RUNTIME;

 import java.lang.annotation.Target;

 /**

  * Marker annotation for a field that is an <em>application state object</em> as controlled by the {@link

  * org.apache.tapestry5.services.ApplicationStateManager}.  <em>Application</em> is something of a misnomer, as it

  * implies that the object is stored as global, application-wide state (i.e., in the {@link

  * javax.servlet.ServletContext}). In fact, the built-in strategies for ASO management are <em>very</em> user specific,

  * ultimately storing data in the {@link org.apache.tapestry5.services.Session}. Because of the confusion this naming

  * causes, this annotation has been deprecated, and the new {@link org.apache.tapestry5.annotations.SessionState}

  * annotation should be used instead.

  * <p/>

  * An ASO field may have a companion field, of type boolean, used to see if the ASO has been created yet. If another

  * field exists with the same name, suffixed with "Exists" (i.e., "aso" for the ASO field, and "asoExists" for the

  * companion field) and the type of that field is boolean, then access to the field will determine whether the ASO has

  * already been created. This is necessary because even a null check ("aso != null") may force the ASO to be created.

  * Instead, check the companion boolean field ("asoExists").

  *

  * @deprecated Use {@link org.apache.tapestry5.annotations.SessionState} instead

  */

 @Target(FIELD)

 @Documented

 @Retention(RUNTIME)

 public @interface ApplicationState

 {

     /**

      * If true (the default), then referencing an field marked with the annotation will create the SSO.  If false, then

      * accessing the field will not create the SSO, it will only allow access to it if it already exists.

      */

     boolean create() default true;

 }