001/*
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase.coprocessor;
020
021import org.apache.yetus.audience.InterfaceAudience;
022
023import java.lang.annotation.ElementType;
024import java.lang.annotation.Inherited;
025import java.lang.annotation.Retention;
026import java.lang.annotation.RetentionPolicy;
027import java.lang.annotation.Target;
028
029/**
030 * Marker annotation that denotes Coprocessors that are core to HBase.
031 * A Core Coprocessor is a CP that realizes a core HBase feature. Features are sometimes
032 * implemented first as a Coprocessor to prove viability. The idea is that once proven, they then
033 * migrate to core. Meantime, HBase Core Coprocessors get this annotation. No other Coprocessors
034 * can carry this annotation.
035 */
036// Core Coprocessors are generally naughty making use of HBase internals doing accesses no
037// Coprocessor should be up to so we mark these special Coprocessors with this annotation and on
038// Coprocessor load, we'll give these Coprocessors a 'richer' Environment with access to internals
039// not allowed other Coprocessors. see the *CoprocessorHost where they do the Coprocessor loadings.
040@Target(ElementType.TYPE)
041@Inherited
042@InterfaceAudience.Private
043@Retention(RetentionPolicy.RUNTIME)
044// This Annotation is not @Documented because I don't want users figuring out its mechanics.
045public @interface CoreCoprocessor {}