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.util.Map;
021import java.util.Optional;
022import org.apache.hadoop.hbase.CoprocessorEnvironment;
023import org.apache.hadoop.hbase.ipc.RpcServer;
024import org.apache.hadoop.hbase.security.User;
025import org.apache.yetus.audience.InterfaceAudience;
026
027/**
028 * This is the only implementation of {@link ObserverContext}, which serves as the interface for
029 * third-party Coprocessor developers.
030 */
031@InterfaceAudience.Private
032public class ObserverContextImpl<E extends CoprocessorEnvironment> implements ObserverContext<E> {
033  private E env;
034  private boolean bypass;
035  /**
036   * Is this operation bypassable?
037   */
038  private final boolean bypassable;
039  private final ObserverRpcCallContext rpcCallContext;
040
041  public ObserverContextImpl(ObserverRpcCallContext rpcCallContext) {
042    this(rpcCallContext, false);
043  }
044
045  public ObserverContextImpl(ObserverRpcCallContext rpcCallContext, boolean bypassable) {
046    this.rpcCallContext = rpcCallContext;
047    this.bypassable = bypassable;
048  }
049
050  @Override
051  public E getEnvironment() {
052    return env;
053  }
054
055  public void prepare(E env) {
056    this.env = env;
057  }
058
059  public boolean isBypassable() {
060    return this.bypassable;
061  }
062
063  @Override
064  public void bypass() {
065    if (!this.bypassable) {
066      throw new UnsupportedOperationException("This method does not support 'bypass'.");
067    }
068    bypass = true;
069  }
070
071  /**
072   * @return {@code true}, if {@link ObserverContext#bypass()} was called by one of the loaded
073   *         coprocessors, {@code false} otherwise.
074   */
075  public boolean shouldBypass() {
076    if (!isBypassable()) {
077      return false;
078    }
079    if (bypass) {
080      bypass = false;
081      return true;
082    }
083    return false;
084  }
085
086  @Override
087  public Optional<ObserverRpcCallContext> getRpcCallContext() {
088    return Optional.ofNullable(rpcCallContext);
089  }
090
091  /**
092   * Instantiates a new ObserverContext instance if the passed reference is <code>null</code> and
093   * sets the environment in the new or existing instance. This allows deferring the instantiation
094   * of a ObserverContext until it is actually needed.
095   * @param <E> The environment type for the context
096   * @param env The coprocessor environment to set
097   * @return An instance of <code>ObserverContext</code> with the environment set
098   */
099  @Deprecated
100  // TODO: Remove this method, ObserverContext should not depend on RpcServer
101  public static <E extends CoprocessorEnvironment> ObserverContext<E> createAndPrepare(E env) {
102    Optional<User> user = RpcServer.getRequestUser();
103    ObserverRpcCallContext rpcCallContext =
104      user.map(value -> new ObserverRpcCallContextImpl(value, Map.of())).orElse(null);
105
106    ObserverContextImpl<E> ctx = new ObserverContextImpl<>(rpcCallContext);
107    ctx.prepare(env);
108
109    return ctx;
110  }
111}