github.com/keysonZZZ/kmg@v0.0.0-20151121023212-05317bfd7d39/kmgRpc/kmgRpcJava/java/src/com/google/gson/annotations/Since.java (about)

     1  /*
     2   * Copyright (C) 2008 Google Inc.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   * http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package com.google.gson.annotations;
    18  
    19  import java.lang.annotation.ElementType;
    20  import java.lang.annotation.Retention;
    21  import java.lang.annotation.RetentionPolicy;
    22  import java.lang.annotation.Target;
    23  
    24  /**
    25   * An annotation that indicates the version number since a member or a type has been present.
    26   * This annotation is useful to manage versioning of your Json classes for a web-service.
    27   *
    28   * <p>
    29   * This annotation has no effect unless you build {@link com.google.gson.Gson} with a
    30   * {@link com.google.gson.GsonBuilder} and invoke
    31   * {@link com.google.gson.GsonBuilder#setVersion(double)} method.
    32   *
    33   * <p>Here is an example of how this annotation is meant to be used:</p>
    34   * <pre>
    35   * public class User {
    36   *   private String firstName;
    37   *   private String lastName;
    38   *   &#64Since(1.0) private String emailAddress;
    39   *   &#64Since(1.0) private String password;
    40   *   &#64Since(1.1) private Address address;
    41   * }
    42   * </pre>
    43   *
    44   * <p>If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()}
    45   * methods will use all the fields for serialization and deserialization. However, if you created
    46   * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.0).create()} then the
    47   * {@code toJson()} and {@code fromJson()} methods of Gson will exclude the {@code address} field
    48   * since it's version number is set to {@code 1.1}.</p>
    49   *
    50   * @author Inderjeet Singh
    51   * @author Joel Leitch
    52   */
    53  @Retention(RetentionPolicy.RUNTIME)
    54  @Target({ElementType.FIELD, ElementType.TYPE})
    55  public @interface Since {
    56    /**
    57     * the value indicating a version number since this member
    58     * or type has been present.
    59     */
    60    double value();
    61  }