henrib commented on code in PR #4194: URL: https://github.com/apache/hive/pull/4194#discussion_r1174258092
########## standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/PropertyManager.java: ########## @@ -0,0 +1,576 @@ +/* + * 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.hive.metastore.properties; + + +import org.apache.commons.jexl3.JexlBuilder; +import org.apache.commons.jexl3.JexlContext; +import org.apache.commons.jexl3.JexlEngine; +import org.apache.commons.jexl3.JexlException; +import org.apache.commons.jexl3.JexlExpression; +import org.apache.commons.jexl3.JexlFeatures; +import org.apache.commons.jexl3.introspection.JexlPermissions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.lang.reflect.Constructor; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Properties; +import java.util.TreeMap; +import java.util.UUID; +import java.util.function.Function; + +/** + * A property manager. + * <p> + * This handles operations at the higher functional level; an instance is created per-session and + * drives queries and updates in a transactional manner. + * </p> + * <p> + * The manager ties the property schemas into one namespace; all property maps it handles must and will use + * one of its known schema. + * </p> + */ +public abstract class PropertyManager { + /** The logger. */ + public static final Logger LOGGER = LoggerFactory.getLogger(PropertyManager.class); + /** The set of dirty maps. */ + protected Map<String, PropertyMap> dirtyMaps = new HashMap<>(); + /** This manager namespace. */ + protected final String namespace; + /** The property map store. */ + protected final PropertyStore store; + /** A Jexl engine for convenience. */ + static final JexlEngine JEXL; + static { + JexlFeatures features = new JexlFeatures() + .sideEffect(false) + .sideEffectGlobal(false); + JexlPermissions p = JexlPermissions.RESTRICTED + .compose("org.apache.hadoop.hive.metastore.properties.*"); + JEXL = new JexlBuilder() + .features(features) + .permissions(p) + .create(); + } + + /** + * The map of defined managers. + */ + private static final Map<String, Constructor<? extends PropertyManager>> NSMANAGERS = new HashMap<>(); Review Comment: Because the property manager owns the property schema(s) and different implementations are expected; we 'replace' modifying the db schema by allowing different property manager namespaces and manager implementations. Next feature that needs to persist metadata properties may create its own (think partitions metadata). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
