dawidwys commented on a change in pull request #10342: [FLINK-14967][table] Add a utility for creating data types via reflection URL: https://github.com/apache/flink/pull/10342#discussion_r351774090
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/extraction/utils/ExtractionUtils.java ########## @@ -0,0 +1,565 @@ +/* + * 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.utils; + +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.table.api.DataTypes; +import org.apache.flink.table.api.ValidationException; +import org.apache.flink.table.catalog.DataTypeLookup; +import org.apache.flink.table.types.DataType; +import org.apache.flink.table.types.logical.StructuredType; + +import org.apache.flink.shaded.asm7.org.objectweb.asm.ClassReader; +import org.apache.flink.shaded.asm7.org.objectweb.asm.ClassVisitor; +import org.apache.flink.shaded.asm7.org.objectweb.asm.Label; +import org.apache.flink.shaded.asm7.org.objectweb.asm.MethodVisitor; +import org.apache.flink.shaded.asm7.org.objectweb.asm.Opcodes; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.lang.reflect.Constructor; +import java.lang.reflect.Field; +import java.lang.reflect.Method; +import java.lang.reflect.Modifier; +import java.lang.reflect.Parameter; +import java.lang.reflect.ParameterizedType; +import java.lang.reflect.Type; +import java.lang.reflect.TypeVariable; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import static org.apache.flink.shaded.asm7.org.objectweb.asm.Type.getConstructorDescriptor; + +/** + * Utilities for performing reflection tasks. + */ +public final class ExtractionUtils { + + /** + * Helper method for creating consistent exceptions during extraction. + */ + public static ValidationException extractionError(String message, Object... args) { + return extractionError(null, message, args); + } + + /** + * Helper method for creating consistent exceptions during extraction. + */ + public static ValidationException extractionError(Throwable cause, String message, Object... args) { + return new ValidationException( + String.format( + message, + args + ), + cause + ); + } + + /** + * Collects the type hierarchy from the given type to the base class. The base class is included + * in the returned hierarchy if it is not {@link Object}. + */ + public static List<Type> collectTypeHierarchy(Class<?> baseClass, Type type) { + Type currentType = type; + Class<?> currentClass = toClass(type); + if (currentClass == null || !baseClass.isAssignableFrom(currentClass)) { + throw extractionError( + "Base class %s is not a super class of type %s.", + baseClass.getName(), + type.toString()); + } + final List<Type> typeHierarchy = new ArrayList<>(); + while (currentClass != baseClass) { + assert currentClass != null; + typeHierarchy.add(currentType); + currentType = currentClass.getGenericSuperclass(); + currentClass = toClass(currentType); + } + if (currentClass != Object.class) { + typeHierarchy.add(currentType); + } + return typeHierarchy; + } + + /** + * Converts a {@link Type} to {@link Class} if possible, {@code null} otherwise. + */ + public static @Nullable Class<?> toClass(Type type) { + if (type instanceof Class) { + return (Class<?>) type; + } else if (type instanceof ParameterizedType) { + // this is always a class + return (Class<?>) ((ParameterizedType) type).getRawType(); + } + // unsupported: generic arrays, type variables, wildcard types + return null; + } + + /** + * Creates a raw data type. + */ + @SuppressWarnings("unchecked") + public static DataType createRawType( + DataTypeLookup lookup, + @Nullable Class<?> rawSerializer, + @Nullable Class<?> conversionClass) { + if (rawSerializer != null) { + return DataTypes.RAW((Class) createConversionClass(conversionClass), instantiateRawSerializer(rawSerializer)); + } + return lookup.resolveRawDataType(createConversionClass(conversionClass)); + } + + private static Class<?> createConversionClass(@Nullable Class<?> conversionClass) { + if (conversionClass != null) { + return conversionClass; + } + return Object.class; + } + + private static TypeSerializer<?> instantiateRawSerializer(Class<?> rawSerializer) { + if (!TypeSerializer.class.isAssignableFrom(rawSerializer)) { + throw extractionError( + "Defined class '%s' for RAW serializer does not extend '%s'.", + rawSerializer.getName(), + TypeSerializer.class.getName() + ); + } + try { + return (TypeSerializer<?>) rawSerializer.newInstance(); + } catch (Exception e) { + throw extractionError( + e, + "Cannot instantiate type serializer '%s' for RAW type. " + + "Make sure the class is publicly accessible and has a default constructor", + rawSerializer.getName() + ); + } + } + + /** + * Resolves a {@link TypeVariable} using the given type hierarchy if possible. + */ + public static Type resolveVariable(List<Type> typeHierarchy, TypeVariable<?> variable) { Review comment: I had hard time understanding this method. I tried to refactor it a bit. Personally found it a bit easier to understand, but that might be subjective. There is one substantial difference that it does not iterate through all the parameters of a ParameterizedType if a matching variable was found. ``` /** * Resolves a {@link TypeVariable} using the given type hierarchy if possible. */ public static Type resolveVariable(List<Type> typeHierarchy, TypeVariable<?> variable) { // iterate through hierarchy from top to bottom until type variable gets a non-variable assigned for (int i = typeHierarchy.size() - 1; i >= 0; i--) { final Type currentType = typeHierarchy.get(i); if (currentType instanceof ParameterizedType) { Type resolvedType = resolveVariableInParameterizedType(variable, (ParameterizedType) currentType); if (resolvedType instanceof TypeVariable) { // follow type variables transitively variable = (TypeVariable<?>) resolvedType; } else if (resolvedType != null) { return resolvedType; } } } // unresolved variable return variable; } private static @Nullable Type resolveVariableInParameterizedType( TypeVariable<?> variable, ParameterizedType currentType) { final Class<?> currentRaw = (Class<?>) currentType.getRawType(); final TypeVariable<?>[] currentVariables = currentRaw.getTypeParameters(); // search for matching type variable for (int paramPos = 0; paramPos < currentVariables.length; paramPos++) { if (equal(variable, currentVariables[paramPos])) { return currentType.getActualTypeArguments()[paramPos]; } } return null; } private static boolean equal(TypeVariable<?> variable, TypeVariable<?> currentVariable) { return currentVariable.getGenericDeclaration().equals(variable.getGenericDeclaration()) && currentVariable.getName().equals(variable.getName()); } ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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