jamesstarr commented on a change in pull request #2603: URL: https://github.com/apache/calcite/pull/2603#discussion_r747745008
########## File path: core/src/main/java/org/apache/calcite/rel/metadata/lambda/ReflectionToLambdaProvider.java ########## @@ -0,0 +1,359 @@ +/* + * 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.calcite.rel.metadata.lambda; + +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.metadata.RelMdAllPredicates; +import org.apache.calcite.rel.metadata.RelMdCollation; +import org.apache.calcite.rel.metadata.RelMdColumnOrigins; +import org.apache.calcite.rel.metadata.RelMdColumnUniqueness; +import org.apache.calcite.rel.metadata.RelMdDistinctRowCount; +import org.apache.calcite.rel.metadata.RelMdDistribution; +import org.apache.calcite.rel.metadata.RelMdExplainVisibility; +import org.apache.calcite.rel.metadata.RelMdExpressionLineage; +import org.apache.calcite.rel.metadata.RelMdLowerBoundCost; +import org.apache.calcite.rel.metadata.RelMdMaxRowCount; +import org.apache.calcite.rel.metadata.RelMdMemory; +import org.apache.calcite.rel.metadata.RelMdMinRowCount; +import org.apache.calcite.rel.metadata.RelMdNodeTypes; +import org.apache.calcite.rel.metadata.RelMdParallelism; +import org.apache.calcite.rel.metadata.RelMdPercentageOriginalRows; +import org.apache.calcite.rel.metadata.RelMdPopulationSize; +import org.apache.calcite.rel.metadata.RelMdPredicates; +import org.apache.calcite.rel.metadata.RelMdRowCount; +import org.apache.calcite.rel.metadata.RelMdSelectivity; +import org.apache.calcite.rel.metadata.RelMdSize; +import org.apache.calcite.rel.metadata.RelMdTableReferences; +import org.apache.calcite.rel.metadata.RelMdUniqueKeys; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.calcite.util.BuiltInMethod; + +import com.google.common.cache.CacheBuilder; +import com.google.common.cache.CacheLoader; +import com.google.common.cache.LoadingCache; +import com.google.common.collect.HashBasedTable; +import com.google.common.collect.ImmutableList; +import com.google.common.collect.Table; +import com.google.common.primitives.Primitives; + +import java.lang.invoke.CallSite; +import java.lang.invoke.LambdaMetafactory; +import java.lang.invoke.MethodHandle; +import java.lang.invoke.MethodHandles; +import java.lang.invoke.MethodType; +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.Locale; +import java.util.Map; +import java.util.concurrent.ExecutionException; +import java.util.stream.Collectors; +import javax.annotation.concurrent.ThreadSafe; + +/** + * Create a set of lambda handlers via reflection patterns. + * + * This does reflection to lambda conversion based on a set of singleton objects + * with appropriate signatures, similar to how ReflectiveRelMetadataProvider works. + * Any class that can be discovered using ReflectiveRelMetadataProvider should also be consumable + * using this class. Ultimately, the goal may be to move to direct lambda registration as opposed to + * the old system of partial reflection discovery. + */ +@ThreadSafe +public class ReflectionToLambdaProvider implements LambdaProvider { + + public static final ImmutableList<Source> DEFAULT_SOURCES = ImmutableList.<Source>builder() Review comment: If this is not the purposed end api, then we should not waste too much time discussing this implementation. But just as the API for metadata retrieval should not expose internals, the API for registering metadata implementations. This has not been the case for the previous api. If your purposed API for this is to register every method the RelNode type instead of discovering them reflectively, then my questions is why do we need some convoluted framework for handling the dispatch instead of just harding coding in the dispatch. Their is pretty much a one to one mapping at that point of the amount of configuration needed compare to explicitly maintaining the implementation. -- 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]
