twalthr commented on a change in pull request #10606: [FLINK-15009][table-common] Add a utility for creating type inference logic via reflection URL: https://github.com/apache/flink/pull/10606#discussion_r364619675
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/extraction/TypeInferenceExtractor.java ########## @@ -0,0 +1,703 @@ +/* + * 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.types.extraction; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.table.annotation.DataTypeHint; +import org.apache.flink.table.annotation.FunctionHint; +import org.apache.flink.table.api.ValidationException; +import org.apache.flink.table.catalog.DataTypeLookup; +import org.apache.flink.table.functions.AggregateFunction; +import org.apache.flink.table.functions.AsyncTableFunction; +import org.apache.flink.table.functions.ScalarFunction; +import org.apache.flink.table.functions.TableAggregateFunction; +import org.apache.flink.table.functions.TableFunction; +import org.apache.flink.table.functions.UserDefinedFunction; +import org.apache.flink.table.types.CollectionDataType; +import org.apache.flink.table.types.DataType; +import org.apache.flink.table.types.extraction.utils.ExtractionUtils; +import org.apache.flink.table.types.extraction.utils.FunctionArgumentTemplate; +import org.apache.flink.table.types.extraction.utils.FunctionResultTemplate; +import org.apache.flink.table.types.extraction.utils.FunctionSignatureTemplate; +import org.apache.flink.table.types.extraction.utils.FunctionTemplate; +import org.apache.flink.table.types.inference.InputTypeStrategies; +import org.apache.flink.table.types.inference.InputTypeStrategy; +import org.apache.flink.table.types.inference.TypeInference; +import org.apache.flink.table.types.inference.TypeStrategies; +import org.apache.flink.table.types.inference.TypeStrategy; + +import javax.annotation.Nullable; + +import java.lang.reflect.Method; +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import java.util.function.Function; +import java.util.stream.Collectors; +import java.util.stream.IntStream; +import java.util.stream.Stream; + +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.collectAnnotationsOfClass; +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.collectAnnotationsOfMethod; +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.collectMethods; +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.extractionError; +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.isAssignable; +import static org.apache.flink.table.types.extraction.utils.ExtractionUtils.isMethodInvokable; + +/** + * Reflection-based utility for extracting a {@link TypeInference} from a supported subclass of + * {@link UserDefinedFunction}. + * + * <p>The behavior of this utility can be influenced by {@link DataTypeHint}s and {@link FunctionHint}s + * which have higher precedence than the reflective information. + * + * <p>Note: This utility assumes that functions have been validated before regarding accessibility of + * class/methods and serializability. + */ +@Internal +public final class TypeInferenceExtractor { + + private final DataTypeLookup lookup; + + private final Class<? extends UserDefinedFunction> function; + + private final String functionExplanation; + + private final String methodName; + + private TypeInferenceExtractor( + DataTypeLookup lookup, + Class<? extends UserDefinedFunction> function, + String functionExplanation, + String methodName) { + this.lookup = lookup; + this.function = function; + this.functionExplanation = functionExplanation; + this.methodName = methodName; + } + + /** + * Extracts a type inference from a {@link ScalarFunction}. + */ + public static TypeInference forScalarFunction(DataTypeLookup lookup, Class<? extends ScalarFunction> function) { + final TypeInferenceExtractor extractor = new TypeInferenceExtractor(lookup, function, "scalar", "eval"); + return extractor.extractTypeInference( + extractor.createParameterSignatureExtraction(false), + null, + extractor.createReturnTypeResultExtraction(), + extractor.createParameterAndReturnTypeVerification() + ); + } + + /** + * Extracts a type inference from a {@link AggregateFunction}. + */ + public static TypeInference forAggregateFunction(DataTypeLookup lookup, Class<? extends AggregateFunction> function) { + final TypeInferenceExtractor extractor = new TypeInferenceExtractor(lookup, function, "aggregate", "accumulate"); + return extractor.extractTypeInference( + extractor.createParameterSignatureExtraction(true), + extractor.createGenericResultExtraction(AggregateFunction.class, 1), + extractor.createGenericResultExtraction(AggregateFunction.class, 0), + extractor.createParameterWithAccumulatorVerification() + ); + } + + /** + * Extracts a type inference from a {@link TableFunction}. + */ + public static TypeInference forTableFunction(DataTypeLookup lookup, Class<? extends TableFunction> function) { + final TypeInferenceExtractor extractor = new TypeInferenceExtractor(lookup, function, "table", "eval"); + return extractor.extractTypeInference( + extractor.createParameterSignatureExtraction(false), + null, + extractor.createGenericResultExtraction(TableFunction.class, 0), + extractor.createParameterVerification() + ); + } + + /** + * Extracts a type inference from a {@link TableAggregateFunction}. + */ + public static TypeInference forTableAggregateFunction(DataTypeLookup lookup, Class<? extends TableAggregateFunction> function) { + final TypeInferenceExtractor extractor = new TypeInferenceExtractor(lookup, function, "table aggregate", "accumulate"); + return extractor.extractTypeInference( + extractor.createParameterSignatureExtraction(true), + extractor.createGenericResultExtraction(TableAggregateFunction.class, 1), + extractor.createGenericResultExtraction(TableAggregateFunction.class, 0), + extractor.createParameterWithAccumulatorVerification() + ); + } + + /** + * Extracts a type inference from a {@link AsyncTableFunction}. + */ + public static TypeInference forAsyncTableFunction(DataTypeLookup lookup, Class<? extends AsyncTableFunction> function) { + final TypeInferenceExtractor extractor = new TypeInferenceExtractor(lookup, function, "async table", "eval"); + return extractor.extractTypeInference( + extractor.createParameterSignatureExtraction(true), + null, + extractor.createGenericResultExtraction(AsyncTableFunction.class, 0), + extractor.createParameterWithArgumentVerification(CompletableFuture.class) + ); + } + + // -------------------------------------------------------------------------------------------- + // Context sensitive extraction and verification logic + // -------------------------------------------------------------------------------------------- + + /** + * Extraction that uses the method parameters for producing a {@link FunctionSignatureTemplate}. + */ + private SignatureExtraction createParameterSignatureExtraction(boolean excludeFirstArg) { + final int offset; + if (excludeFirstArg) { + offset = 1; + } else { + offset = 0; + } + return method -> { + // argument types + final List<FunctionArgumentTemplate> parameterTypes = IntStream.range(offset, method.getParameterCount()) + .mapToObj(i -> { + final DataType type = DataTypeExtractor.extractFromMethodParameter(lookup, function, method, i); + // unwrap from ARRAY data type in case of varargs + if (method.isVarArgs() && i == method.getParameterCount() - 1 && type instanceof CollectionDataType) { + return ((CollectionDataType) type).getElementDataType(); + } else { + return type; + } + }) + .map(FunctionArgumentTemplate::of) + .collect(Collectors.toList()); + + // argument names + final List<String> methodParameterNames = ExtractionUtils.extractMethodParameterNames(method); + final String[] argumentNames; + if (methodParameterNames != null) { + argumentNames = methodParameterNames.subList(offset, methodParameterNames.size()) + .toArray(new String[0]); + } else { + argumentNames = null; + } + + return FunctionSignatureTemplate.of(parameterTypes, method.isVarArgs(), argumentNames); + }; + } + + /** + * Extraction that uses a generic type variable for producing a {@link FunctionResultTemplate}. + */ + private ResultExtraction createGenericResultExtraction( + Class<? extends UserDefinedFunction> baseClass, + int genericPos) { + return (method) -> { + final DataType dataType = DataTypeExtractor.extractFromGeneric(lookup, baseClass, genericPos, function); + return FunctionResultTemplate.of(dataType); + }; + } + + /** + * Extraction that uses the method return type for producing a {@link FunctionResultTemplate}. + */ + private ResultExtraction createReturnTypeResultExtraction() { + return (method) -> { + final DataType dataType = DataTypeExtractor.extractFromMethodOutput(lookup, function, method); + return FunctionResultTemplate.of(dataType); + }; + } + + /** + * Verification that checks a method by parameters and return type. + */ + private MethodVerification createParameterAndReturnTypeVerification() { + return (method, signature, accumulator, output) -> { + final Class<?>[] parameters = signature.toArray(new Class[0]); + final Class<?> returnType = method.getReturnType(); + final boolean isValid = isMethodInvokable(method, parameters) && + isAssignable(output, returnType, true); Review comment: Yes, the conversion class is the source of truth for the planner. But the method return type can be a super class. E.g. `eval(): Number` and the conversion class (e.g. `Integer`) must be castable to `Number` for the method. In the code generator we perform `(Integer) number`. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
