<filename>SWayfarer's Lib II/src/ru/swayfarer/swl2/z/dependencies/com/google/gson/annotations/Since.java
/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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 ru.swayfarer.swl2.z.dependencies.com.google.gson.annotations;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * An annotation that indicates the version number since a member or a type has been present.
 * This annotation is useful to manage versioning of your Json classes for a Webservice. 
 * 
 * <p>
 * This annotation has no effect unless you build {@link ru.swayfarer.swl2.z.dependencies.com.google.gson.Gson} with a 
 * {@link ru.swayfarer.swl2.z.dependencies.com.google.gson.GsonBuilder} and invoke 
 * {@link ru.swayfarer.swl2.z.dependencies.com.google.gson.GsonBuilder#setVersion(double)} method.
 * 
 * <p>Here is an example of how this annotation is meant to be used: 
 * <p><code>
 * public class User {<br>
 * &nbsp; private String firstName;<br>
 * &nbsp; private String lastName;<br>
 * &nbsp; @Since(1.0) private String emailAddress;<br>
 * &nbsp; @Since(1.0) private String password;<br>
 * &nbsp; @Since(1.1) private Address address;<br>
 * }<br>
 * </code></p>
 * 
 * <p>If you created Gson with <code>new Gson()</code>, the <code>toJson()</code> and 
 * <code>fromJson()</code> methods will use all the fields for serialization and deserialization.
 * However, if you created Gson with 
 * <code>Gson gson = new GsonBuilder().setVersion(1.0).create()</code>
 * then the <code>toJson()</code> and <code>fromJson()</code> methods of Gson will exclude 
 * the <code>address</code> field since it's version number is set to <code>1.1</code>.</p>
 *  
 * @author <NAME>
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})
public @interface Since {
  /**
   * the value indicating a version number since this member
   * or type has been present. 
   */
  double value();
}
