content: /*
   * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package javac.internal;
  
  import java.lang.annotation.Target;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  
  /**
   * Indicates the API declaration in question is associated with a
   * <em>preview feature</em>. See JEP 12: "Preview Language and VM
   * Features" (http://openjdk.java.net/jeps/12).
   *
   * Note this internal annotation is handled specially by the javac compiler.
   * To work properly with {@code --release older-release}, it requires special
   * handling in {@code make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java}
   * and {@code src/jdk.compiler/share/classes/openjdk/tools/javac/jvm/ClassReader.java}.
   *
   * @since 14
   */
  // Match the meaningful targets of java.lang.Deprecated, omit local
  // variables and parameter declarations
  @Target({java.lang.annotation.ElementType.METHOD,
           java.lang.annotation.ElementType.CONSTRUCTOR,
           java.lang.annotation.ElementType.FIELD,
           java.lang.annotation.ElementType.PACKAGE,
           java.lang.annotation.ElementType.TYPE})
   // CLASS retention will hopefully be sufficient for the purposes at hand
  @Retention(RetentionPolicy.CLASS)
  // *Not* @Documented
  public @interface PreviewFeature {
      /**
       * Name of the preview feature the annotated API is associated
       * with.
       */
      public Feature feature();
  
      public boolean reflective() default false;
  
      public enum Feature {
          SWITCH_PATTERN_MATCHING,
          /**
           * A key for testing.
           */
          TEST,
          ;
      }
  }
  