001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 package org.apache.hadoop.classification;
019
020 import java.lang.annotation.Documented;
021 import java.lang.annotation.Retention;
022 import java.lang.annotation.RetentionPolicy;
023
024 /**
025 * Annotation to inform users of a package, class or method's intended audience.
026 */
027 @InterfaceAudience.Public
028 @InterfaceStability.Evolving
029 public class InterfaceAudience {
030 /**
031 * Intended for use by any project or application.
032 */
033 @Documented
034 @Retention(RetentionPolicy.RUNTIME)
035 public @interface Public {};
036
037 /**
038 * Intended only for the project(s) specified in the annotation.
039 * For example, "Common", "HDFS", "MapReduce", "ZooKeeper", "HBase".
040 */
041 @Documented
042 @Retention(RetentionPolicy.RUNTIME)
043 public @interface LimitedPrivate {
044 String[] value();
045 };
046
047 /**
048 * Intended for use only within Hadoop itself.
049 */
050 @Documented
051 @Retention(RetentionPolicy.RUNTIME)
052 public @interface Private {};
053
054 private InterfaceAudience() {} // Audience can't exist on its own
055 }