| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.hadoop.hbase.coprocessor; |
| |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| import org.apache.hadoop.hbase.classification.InterfaceStability; |
| import org.apache.hadoop.hbase.CoprocessorEnvironment; |
| import org.apache.hadoop.hbase.HBaseInterfaceAudience; |
| import org.apache.hadoop.hbase.ipc.RpcServer; |
| import org.apache.hadoop.hbase.security.User; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Carries the execution state for a given invocation of an Observer coprocessor |
| * ({@link RegionObserver}, {@link MasterObserver}, or {@link WALObserver}) |
| * method. The same ObserverContext instance is passed sequentially to all loaded |
| * coprocessors for a given Observer method trigger, with the |
| * <code>CoprocessorEnvironment</code> reference swapped out for each |
| * coprocessor. |
| * @param <E> The {@link CoprocessorEnvironment} subclass applicable to the |
| * revelant Observer interface. |
| */ |
| @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC) |
| @InterfaceStability.Evolving |
| public class ObserverContext<E extends CoprocessorEnvironment> { |
| private E env; |
| private boolean bypass; |
| private boolean complete; |
| private User caller; |
| |
| public ObserverContext(User caller) { |
| this.caller = caller; |
| } |
| |
| public E getEnvironment() { |
| return env; |
| } |
| |
| public void prepare(E env) { |
| this.env = env; |
| } |
| |
| /** |
| * Call to indicate that the current coprocessor's return value should be |
| * used in place of the normal HBase obtained value. |
| */ |
| public void bypass() { |
| bypass = true; |
| } |
| |
| /** |
| * Call to indicate that additional coprocessors further down the execution |
| * chain do not need to be invoked. Implies that this coprocessor's response |
| * is definitive. |
| */ |
| public void complete() { |
| complete = true; |
| } |
| |
| /** |
| * For use by the coprocessor framework. |
| * @return <code>true</code> if {@link ObserverContext#bypass()} |
| * was called by one of the loaded coprocessors, <code>false</code> otherwise. |
| */ |
| public boolean shouldBypass() { |
| boolean current = bypass; |
| bypass = false; |
| return current; |
| } |
| |
| /** |
| * For use by the coprocessor framework. |
| * @return <code>true</code> if {@link ObserverContext#complete()} |
| * was called by one of the loaded coprocessors, <code>false</code> otherwise. |
| */ |
| public boolean shouldComplete() { |
| boolean current = complete; |
| complete = false; |
| return current; |
| } |
| |
| /** |
| * Returns the active user for the coprocessor call. |
| * If an explicit {@code User} instance was provided to the constructor, that will be returned, |
| * otherwise if we are in the context of an RPC call, the remote user is used. May return null |
| * if the execution is outside of an RPC context. |
| */ |
| @Nullable |
| public User getCaller() { |
| return caller; |
| } |
| |
| /** |
| * Instantiates a new ObserverContext instance if the passed reference is |
| * <code>null</code> and sets the environment in the new or existing instance. |
| * This allows deferring the instantiation of a ObserverContext until it is |
| * actually needed. |
| * |
| * @param env The coprocessor environment to set |
| * @param context An existing ObserverContext instance to use, or <code>null</code> |
| * to create a new instance |
| * @param <T> The environment type for the context |
| * @return An instance of <code>ObserverContext</code> with the environment set |
| */ |
| @Deprecated |
| // TODO: Remove this method, ObserverContext should not depend on RpcServer |
| public static <T extends CoprocessorEnvironment> ObserverContext<T> createAndPrepare( |
| T env, ObserverContext<T> context) { |
| if (context == null) { |
| context = new ObserverContext<T>(RpcServer.getRequestUser()); |
| } |
| context.prepare(env); |
| return context; |
| } |
| |
| /** |
| * Instantiates a new ObserverContext instance if the passed reference is |
| * <code>null</code> and sets the environment in the new or existing instance. |
| * This allows deferring the instantiation of a ObserverContext until it is |
| * actually needed. |
| * |
| * @param env The coprocessor environment to set |
| * @param context An existing ObserverContext instance to use, or <code>null</code> |
| * to create a new instance |
| * @param user The requesting caller for the execution context |
| * @param <T> The environment type for the context |
| * @return An instance of <code>ObserverContext</code> with the environment set |
| */ |
| public static <T extends CoprocessorEnvironment> ObserverContext<T> createAndPrepare( |
| T env, ObserverContext<T> context, User user) { |
| if (context == null) { |
| context = new ObserverContext<T>(user); |
| } |
| context.prepare(env); |
| return context; |
| } |
| } |