/* * 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 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 until a member or a type should be present. * Basically, if Gson is created with a version number that exceeds the value stored in the * {@code Until} annotation then the field will be ignored from the JSON output.  This annotation * is useful to manage versioning of your JSON classes for a web-service. * * <p> * This annotation has no effect unless you build {@link com.google.gson.Gson} with a * {@link com.google.gson.GsonBuilder} and invoke * {@link com.google.gson.GsonBuilder#setVersion(double)} method. * * <p>Here is an example of how this annotation is meant to be used:</p> * <pre> * public class User { *   private String firstName; *   private String lastName; *   &#64Until(1.1) private String emailAddress; *   &#64Until(1.1) private String password; * } * </pre> * * <p>If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()} * methods will use all the fields for serialization and deserialization. However, if you created * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.2).create()} then the * {@code toJson()} and {@code fromJson()} methods of Gson will exclude the {@code emailAddress} * and {@code password} fields from the example above, because the version number passed to the  * GsonBuilder, {@code 1.2}, exceeds the version number set on the {@code Until} annotation, * {@code 1.1}, for those fields. * * @author Inderjeet Singh * @author Joel Leitch * @since 1.3 */@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.FIELD, ElementType.TYPE})public @interface Until {  /**   * the value indicating a version number until this member   * or type should be ignored.   */  double value();}