dawidwys commented on a change in pull request #8050: [FLINK-11067][table] Convert TableEnvironments to interfaces URL: https://github.com/apache/flink/pull/8050#discussion_r276182707
########## File path: flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/factories/TableFactoryService.java ########## @@ -0,0 +1,363 @@ +/* + * 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.flink.table.factories; + +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.table.api.AmbiguousTableFactoryException; +import org.apache.flink.table.api.NoMatchingTableFactoryException; +import org.apache.flink.table.api.TableException; +import org.apache.flink.table.descriptors.Descriptor; +import org.apache.flink.table.descriptors.FormatDescriptorValidator; +import org.apache.flink.table.descriptors.Schema; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.HashMap; +import java.util.LinkedList; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.ServiceConfigurationError; +import java.util.ServiceLoader; +import java.util.Set; +import java.util.concurrent.atomic.AtomicReference; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import static org.apache.flink.table.descriptors.ConnectorDescriptorValidator.CONNECTOR_PROPERTY_VERSION; +import static org.apache.flink.table.descriptors.ExternalCatalogDescriptorValidator.CATALOG_PROPERTY_VERSION; +import static org.apache.flink.table.descriptors.FormatDescriptorValidator.FORMAT_PROPERTY_VERSION; +import static org.apache.flink.table.descriptors.MetadataValidator.METADATA_PROPERTY_VERSION; +import static org.apache.flink.table.descriptors.StatisticsValidator.STATISTICS_PROPERTY_VERSION; + +/** + * Unified class to search for a {@link TableFactory} of provided type and properties. + */ +public class TableFactoryService { + + private static final ServiceLoader<TableFactory> defaultLoader = ServiceLoader.load(TableFactory.class); + private static final transient Logger LOG = LoggerFactory.getLogger(TableFactoryService.class); + + /** + * Finds a table factory of the given class and descriptor. + * + * @param factoryClass desired factory class + * @param descriptor descriptor describing the factory configuration + * @param <T> factory class type + * @return the matching factory + */ + public static <T> T find(Class<T> factoryClass, Descriptor descriptor) { + Preconditions.checkNotNull(descriptor); + return findInternal(factoryClass, descriptor.toProperties(), Optional.empty()); + } + + /** + * Finds a table factory of the given class, descriptor, and classloader. + * + * @param factoryClass desired factory class + * @param descriptor descriptor describing the factory configuration + * @param classLoader classloader for service loading + * @param <T> factory class type + * @return the matching factory + */ + public static <T> T find(Class<T> factoryClass, Descriptor descriptor, ClassLoader classLoader) { + Preconditions.checkNotNull(descriptor); + Preconditions.checkNotNull(classLoader); + return findInternal(factoryClass, descriptor.toProperties(), Optional.of(classLoader)); + } + + /** + * Finds a table factory of the given class and property map. + * + * @param factoryClass desired factory class + * @param propertyMap properties that describe the factory configuration + * @param <T> factory class type + * @return the matching factory + */ + public static <T> T find(Class<T> factoryClass, Map<String, String> propertyMap) { + return findInternal(factoryClass, propertyMap, Optional.empty()); + } + + /** + * Finds a table factory of the given class, property map, and classloader. + * + * @param factoryClass desired factory class + * @param propertyMap properties that describe the factory configuration + * @param classLoader classloader for service loading + * @param <T> factory class type + * @return the matching factory + */ + public static <T> T find(Class<T> factoryClass, Map<String, String> propertyMap, ClassLoader classLoader) { + Preconditions.checkNotNull(classLoader); + return findInternal(factoryClass, propertyMap, Optional.of(classLoader)); + } + + /** + * Finds a table factory of the given class, property map, and classloader. + * + * @param factoryClass desired factory class + * @param properties properties that describe the factory configuration + * @param classLoader classloader for service loading + * @param <T> factory class type + * @return the matching factory + */ + public static <T> T findInternal(Class<T> factoryClass, Map<String, String> properties, Optional<ClassLoader> classLoader) { + + Preconditions.checkNotNull(factoryClass); + Preconditions.checkNotNull(properties); + + List<TableFactory> foundFactories = discoverFactories(classLoader); + + List<TableFactory> classFactories = filterByFactoryClass( + factoryClass, + properties, + foundFactories); + + List<TableFactory> contextFactories = filterByContext( + factoryClass, + properties, + foundFactories, + classFactories); + + return filterBySupportedProperties( + factoryClass, + properties, + foundFactories, + contextFactories); + } + + /** + * Searches for factories using Java service providers. + * + * @return all factories in the classpath + */ + private static List<TableFactory> discoverFactories(Optional<ClassLoader> classLoader) { + try { + List<TableFactory> result = new LinkedList<>(); + if (classLoader.isPresent()) { + ServiceLoader + .load(TableFactory.class, classLoader.get()) + .iterator() + .forEachRemaining(result::add); + } else { + defaultLoader.iterator().forEachRemaining(result::add); + } + return result; + } catch (ServiceConfigurationError e) { + LOG.error("Could not load service provider for table factories.", e); + throw new TableException("Could not load service provider for table factories.", e); + } + + } + + /** + * Filters factories with matching context by factory class. + */ + private static <T> List<TableFactory> filterByFactoryClass( + Class<T> factoryClass, + Map<String, String> properties, + List<TableFactory> foundFactories) { + + List<TableFactory> classFactories = foundFactories.stream() + .filter(p -> factoryClass.isAssignableFrom(p.getClass())) + .collect(Collectors.toList()); + + if (classFactories.isEmpty()) { + throw new NoMatchingTableFactoryException( + String.format("No factory implements '%s'.", factoryClass.getCanonicalName()), + factoryClass, + foundFactories, + properties); + } + + return classFactories; + } + + /** + * Filters for factories with matching context. + * + * @return all matching factories + */ + private static <T> List<TableFactory> filterByContext( + Class<T> factoryClass, + Map<String, String> properties, + List<TableFactory> foundFactories, + List<TableFactory> classFactories) { + + List<TableFactory> matchingFactories = classFactories.stream().filter(factory -> { + Map<String, String> requestedContext = normalizeContext(factory); + + Map<String, String> plainContext = new HashMap<>(requestedContext); + // we remove the version for now until we have the first backwards compatibility case + // with the version we can provide mappings in case the format changes + plainContext.remove(CONNECTOR_PROPERTY_VERSION); + plainContext.remove(FORMAT_PROPERTY_VERSION); + plainContext.remove(METADATA_PROPERTY_VERSION); + plainContext.remove(STATISTICS_PROPERTY_VERSION); + plainContext.remove(CATALOG_PROPERTY_VERSION); + + // check if required context is met + return plainContext.keySet().stream().allMatch(e -> properties.containsKey(e) && properties.get(e).equals(plainContext.get(e))); + }).collect(Collectors.toList()); + + if (matchingFactories.isEmpty()) { + throw new NoMatchingTableFactoryException( + "No context matches.", + factoryClass, + foundFactories, + properties); + } + + return matchingFactories; + } + + /** + * Prepares the properties of a context to be used for match operations. + */ + private static Map<String, String> normalizeContext(TableFactory factory) { + Map<String, String> requiredContext = factory.requiredContext(); + if (requiredContext == null) { + throw new TableException( + String.format("Required context of factory '%s' must not be null.", factory.getClass().getName())); + } + return requiredContext.keySet().stream() + .collect(Collectors.toMap(key -> key.toLowerCase(), key -> requiredContext.get(key))); + } + + /** + * Filters the matching class factories by supported properties. + */ + private static <T> T filterBySupportedProperties( + Class<T> factoryClass, + Map<String, String> properties, + List<TableFactory> foundFactories, + List<TableFactory> classFactories) { + + final List<String> plainGivenKeys = new LinkedList<>(); + properties.keySet().forEach(k -> { + // replace arrays with wildcard + String key = k.replaceAll(".\\d+", ".#"); + // ignore duplicates + if (!plainGivenKeys.contains(key)) { + plainGivenKeys.add(key); + } + }); + + AtomicReference<Optional<String>> lastKey = new AtomicReference<>(Optional.empty()); + List<TableFactory> supportedFactories = classFactories.stream().filter(factory -> { + Set<String> requiredContextKeys = normalizeContext(factory).keySet(); + Tuple2<List<String>, List<String>> tuple2 = normalizeSupportedProperties(factory); + // ignore context keys + Stream<String> givenContextFreeKeys = plainGivenKeys.stream().filter(p -> !requiredContextKeys.contains(p)); + Stream<String> givenFilteredKeys = filterSupportedPropertiesFactorySpecific( + factory, + givenContextFreeKeys); + + return givenFilteredKeys.allMatch(k -> { + lastKey.set(Optional.of(k)); + return tuple2.f0.contains(k) || tuple2.f1.stream().anyMatch(p -> k.startsWith(p)); + }); + }).collect(Collectors.toList()); + + if (supportedFactories.isEmpty() && classFactories.size() == 1 && lastKey.get().isPresent()) { + // special case: when there is only one matching factory but the last property key + // was incorrect + TableFactory factory = classFactories.get(0); + Tuple2<List<String>, List<String>> tuple2 = normalizeSupportedProperties(factory); + + String errorMessage = "The matching factory '" + factory.getClass().getName() + "' doesn't support '" + lastKey.get().get() + "'.\n" + Review comment: Use `String.format()` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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