gson-comments/gson/src/main/java/com/google/gson/annotations/Until.java

71 lines
2.7 KiB
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 com.google.gson.annotations;
import com.google.gson.GsonBuilder;
import java.lang.annotation.Documented;
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 is equal to or 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 {@code
* GsonBuilder} and invoke the {@link GsonBuilder#setVersion(double)} method.
*
* <p>Here is an example of how this annotation is meant to be used:
*
* <pre>
* public class User {
* private String firstName;
* private String lastName;
* &#64;Until(1.1) private String emailAddress;
* &#64;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
* @see GsonBuilder#setVersion(double)
* @see Since
* @since 1.3
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.TYPE})
public @interface Until {
/**
* The value indicating a version number until this member or type should be included. The number
* is exclusive; annotated elements will be included if {@code gsonVersion < value}.
*/
double value();
}