1 /*

     2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package jdk.internal;

    27 

    28 import java.lang.annotation.*;

    29 

    30 /**

    31  * Indicates the API declaration in question is associated with a

    32  * <em>preview feature</em>. See JEP 12: "Preview Language and VM

    33  * Features" (http://openjdk.java.net/jeps/12).

    34  * @since 14

    35  */

    36 // Match the meaningful targets of java.lang.Deprecated, omit local

    37 // variables and parameter declarations

    38 @Target({ElementType.METHOD,

    39          ElementType.CONSTRUCTOR,

    40          ElementType.FIELD,

    41          ElementType.PACKAGE,

    42          ElementType.MODULE,

    43          ElementType.TYPE})

    44  // CLASS retention will hopefully be sufficient for the purposes at hand

    45 @Retention(RetentionPolicy.CLASS)

    46 // *Not* @Documented

    47 public @interface PreviewFeature {

    48     /**

    49      * Name of the preview feature the annotated API is associated

    50      * with.

    51      */

    52     public Feature feature();

    53 

    54     public boolean essentialAPI() default false;

    55 

    56     public enum Feature {

    57         SWITCH_EXPRESSIONS,

    58         TEXT_BLOCKS;

    59     }

    60 }