Java tutorial
/** * 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 * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * 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.hive.ql; import java.util.ArrayList; import java.util.List; import com.google.common.collect.Iterables; import org.apache.hadoop.hive.conf.HiveConf; import org.apache.hadoop.hive.ql.hooks.HookContext; import org.apache.hadoop.hive.ql.hooks.HooksLoader; import org.apache.hadoop.hive.ql.hooks.MetricsQueryLifeTimeHook; import org.apache.hadoop.hive.ql.hooks.QueryLifeTimeHook; import org.apache.hadoop.hive.ql.hooks.QueryLifeTimeHookContext; import org.apache.hadoop.hive.ql.hooks.QueryLifeTimeHookContextImpl; import org.apache.hadoop.hive.ql.hooks.QueryLifeTimeHookWithParseHooks; import org.apache.hadoop.hive.ql.session.SessionState; /** * A runner class for {@link QueryLifeTimeHook}s and {@link QueryLifeTimeHookWithParseHooks}. The class has run methods * for each phase of a {@link QueryLifeTimeHook} and {@link QueryLifeTimeHookWithParseHooks}. Each run method checks if * a list of hooks has be specified, and if so invokes the appropriate callback method of each hook. Each method * constructs a {@link QueryLifeTimeHookContext} object and pass it to the callback functions. */ class QueryLifeTimeHookRunner { private final HiveConf conf; private final List<QueryLifeTimeHook> queryHooks; /** * Constructs a {@link QueryLifeTimeHookRunner} that loads all hooks to be run via a {@link HooksLoader}. * * @param conf the {@link HiveConf} to use when creating {@link QueryLifeTimeHookContext} objects * @param hooksLoader the {@link HooksLoader} to use when loading all hooks to be run * @param console the {@link SessionState.LogHelper} to use when running {@link HooksLoader#getHooks(HiveConf.ConfVars)} */ QueryLifeTimeHookRunner(HiveConf conf, HooksLoader hooksLoader, SessionState.LogHelper console) { this.conf = conf; this.queryHooks = new ArrayList<>(); if (conf.getBoolVar(HiveConf.ConfVars.HIVE_SERVER2_METRICS_ENABLED)) { queryHooks.add(new MetricsQueryLifeTimeHook()); } List<QueryLifeTimeHook> propertyDefinedHoooks; try { propertyDefinedHoooks = hooksLoader.getHooks(HiveConf.ConfVars.HIVE_QUERY_LIFETIME_HOOKS, console); } catch (IllegalAccessException | InstantiationException | ClassNotFoundException e) { throw new IllegalArgumentException(e); } if (propertyDefinedHoooks != null) { Iterables.addAll(queryHooks, propertyDefinedHoooks); } } /** * If {@link QueryLifeTimeHookWithParseHooks} have been loaded via the {@link HooksLoader} then invoke the * {@link QueryLifeTimeHookWithParseHooks#beforeParse(QueryLifeTimeHookContext)} method for each * {@link QueryLifeTimeHookWithParseHooks}. * * @param command the Hive command that is being run */ void runBeforeParseHook(String command) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).build(); for (QueryLifeTimeHook hook : queryHooks) { if (hook instanceof QueryLifeTimeHookWithParseHooks) { ((QueryLifeTimeHookWithParseHooks) hook).beforeParse(qhc); } } } } /** * If {@link QueryLifeTimeHookWithParseHooks} have been loaded via the {@link HooksLoader} then invoke the * {@link QueryLifeTimeHookWithParseHooks#afterParse(QueryLifeTimeHookContext, boolean)} method for each * {@link QueryLifeTimeHookWithParseHooks}. * * @param command the Hive command that is being run * @param parseError true if there was an error while parsing the command, false otherwise */ void runAfterParseHook(String command, boolean parseError) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).build(); for (QueryLifeTimeHook hook : queryHooks) { if (hook instanceof QueryLifeTimeHookWithParseHooks) { ((QueryLifeTimeHookWithParseHooks) hook).afterParse(qhc, parseError); } } } } /** * Invoke the {@link QueryLifeTimeHook#beforeCompile(QueryLifeTimeHookContext)} method for each {@link QueryLifeTimeHook} * * @param command the Hive command that is being run */ void runBeforeCompileHook(String command) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).build(); for (QueryLifeTimeHook hook : queryHooks) { hook.beforeCompile(qhc); } } } /** * Invoke the {@link QueryLifeTimeHook#afterCompile(QueryLifeTimeHookContext, boolean)} method for each {@link QueryLifeTimeHook} * * @param command the Hive command that is being run * @param compileError true if there was an error while compiling the command, false otherwise */ void runAfterCompilationHook(String command, boolean compileError) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).build(); for (QueryLifeTimeHook hook : queryHooks) { hook.afterCompile(qhc, compileError); } } } /** * Invoke the {@link QueryLifeTimeHook#beforeExecution(QueryLifeTimeHookContext)} method for each {@link QueryLifeTimeHook} * * @param command the Hive command that is being run * @param hookContext the {@link HookContext} of the command being run */ void runBeforeExecutionHook(String command, HookContext hookContext) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).withHookContext(hookContext).build(); for (QueryLifeTimeHook hook : queryHooks) { hook.beforeExecution(qhc); } } } /** * Invoke the {@link QueryLifeTimeHook#afterExecution(QueryLifeTimeHookContext, boolean)} method for each {@link QueryLifeTimeHook} * * @param command the Hive command that is being run * @param hookContext the {@link HookContext} of the command being run * @param executionError true if there was an error while executing the command, false otherwise */ void runAfterExecutionHook(String command, HookContext hookContext, boolean executionError) { if (containsHooks()) { QueryLifeTimeHookContext qhc = new QueryLifeTimeHookContextImpl.Builder().withHiveConf(conf) .withCommand(command).withHookContext(hookContext).build(); for (QueryLifeTimeHook hook : queryHooks) { hook.afterExecution(qhc, executionError); } } } private boolean containsHooks() { return queryHooks != null && !queryHooks.isEmpty(); } }