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/*
* 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;
* @Until(1.1) private String emailAddress;
* @Until(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();
}
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