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 */
018package org.apache.hadoop.hbase.coprocessor;
019
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Inherited;
022import java.lang.annotation.Retention;
023import java.lang.annotation.RetentionPolicy;
024import java.lang.annotation.Target;
025import org.apache.yetus.audience.InterfaceAudience;
026
027/**
028 * Marker annotation that denotes Coprocessors that are core to HBase. A Core Coprocessor is a CP
029 * that realizes a core HBase feature. Features are sometimes implemented first as a Coprocessor to
030 * prove viability. The idea is that once proven, they then migrate to core. Meantime, HBase Core
031 * Coprocessors get this annotation. No other Coprocessors can carry this annotation.
032 */
033// Core Coprocessors are generally naughty making use of HBase internals doing accesses no
034// Coprocessor should be up to so we mark these special Coprocessors with this annotation and on
035// Coprocessor load, we'll give these Coprocessors a 'richer' Environment with access to internals
036// not allowed other Coprocessors. see the *CoprocessorHost where they do the Coprocessor loadings.
037@Target(ElementType.TYPE)
038@Inherited
039@InterfaceAudience.Private
040@Retention(RetentionPolicy.RUNTIME)
041// This Annotation is not @Documented because I don't want users figuring out its mechanics.
042public @interface CoreCoprocessor {
043}