github.com/keysonZZZ/kmg@v0.0.0-20151121023212-05317bfd7d39/kmgRpc/kmgRpcJava/java/src/com/google/gson/annotations/Until.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 until a member or a type should be present.
    26   * Basically, if Gson is created with a version number that exceeds the value stored in the
    27   * {@code Until} annotation then the field will be ignored from the JSON output.  This annotation
    28   * is useful to manage versioning of your JSON classes for a web-service.
    29   *
    30   * <p>
    31   * This annotation has no effect unless you build {@link com.google.gson.Gson} with a
    32   * {@link com.google.gson.GsonBuilder} and invoke
    33   * {@link com.google.gson.GsonBuilder#setVersion(double)} method.
    34   *
    35   * <p>Here is an example of how this annotation is meant to be used:</p>
    36   * <pre>
    37   * public class User {
    38   *   private String firstName;
    39   *   private String lastName;
    40   *   &#64Until(1.1) private String emailAddress;
    41   *   &#64Until(1.1) private String password;
    42   * }
    43   * </pre>
    44   *
    45   * <p>If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()}
    46   * methods will use all the fields for serialization and deserialization. However, if you created
    47   * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.2).create()} then the
    48   * {@code toJson()} and {@code fromJson()} methods of Gson will exclude the {@code emailAddress}
    49   * and {@code password} fields from the example above, because the version number passed to the 
    50   * GsonBuilder, {@code 1.2}, exceeds the version number set on the {@code Until} annotation,
    51   * {@code 1.1}, for those fields.
    52   *
    53   * @author Inderjeet Singh
    54   * @author Joel Leitch
    55   * @since 1.3
    56   */
    57  @Retention(RetentionPolicy.RUNTIME)
    58  @Target({ElementType.FIELD, ElementType.TYPE})
    59  public @interface Until {
    60  
    61    /**
    62     * the value indicating a version number until this member
    63     * or type should be ignored.
    64     */
    65    double value();
    66  }