| /* |
| * 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.beam.sdk.extensions.sql.impl; |
| |
| import static org.apache.calcite.util.Static.RESOURCE; |
| |
| import java.lang.reflect.Constructor; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Modifier; |
| import org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.ImmutableMultimap; |
| import org.apache.calcite.adapter.enumerable.CallImplementor; |
| import org.apache.calcite.adapter.enumerable.NullPolicy; |
| import org.apache.calcite.adapter.enumerable.ReflectiveCallNotNullImplementor; |
| import org.apache.calcite.adapter.enumerable.RexImpTable; |
| import org.apache.calcite.linq4j.function.SemiStrict; |
| import org.apache.calcite.linq4j.function.Strict; |
| import org.apache.calcite.rel.type.RelDataType; |
| import org.apache.calcite.rel.type.RelDataTypeFactory; |
| import org.apache.calcite.schema.Function; |
| import org.apache.calcite.schema.ImplementableFunction; |
| import org.apache.calcite.schema.ScalarFunction; |
| import org.apache.calcite.sql.SqlOperatorBinding; |
| |
| /** |
| * Beam-customized version from {@link org.apache.calcite.schema.impl.ScalarFunctionImpl}, to |
| * address BEAM-5921. |
| */ |
| public class ScalarFunctionImpl extends UdfImplReflectiveFunctionBase |
| implements ScalarFunction, ImplementableFunction { |
| |
| private final CallImplementor implementor; |
| |
| /** Private constructor. */ |
| private ScalarFunctionImpl(Method method, CallImplementor implementor) { |
| super(method); |
| this.implementor = implementor; |
| } |
| |
| /** Creates {@link org.apache.calcite.schema.Function} for each method in a given class. */ |
| public static ImmutableMultimap<String, Function> createAll(Class<?> clazz) { |
| final ImmutableMultimap.Builder<String, Function> builder = ImmutableMultimap.builder(); |
| for (Method method : clazz.getMethods()) { |
| if (method.getDeclaringClass() == Object.class) { |
| continue; |
| } |
| if (!Modifier.isStatic(method.getModifiers()) && !classHasPublicZeroArgsConstructor(clazz)) { |
| continue; |
| } |
| final Function function = create(method); |
| builder.put(method.getName(), function); |
| } |
| return builder.build(); |
| } |
| |
| /** |
| * Creates {@link org.apache.calcite.schema.Function} from given class. |
| * |
| * <p>If a method of the given name is not found or it does not suit, returns {@code null}. |
| * |
| * @param clazz class that is used to implement the function |
| * @param methodName Method name (typically "eval") |
| * @return created {@link ScalarFunction} or null |
| */ |
| public static Function create(Class<?> clazz, String methodName) { |
| final Method method = findMethod(clazz, methodName); |
| if (method == null) { |
| return null; |
| } |
| return create(method); |
| } |
| |
| /** |
| * Creates {@link org.apache.calcite.schema.Function} from given method. When {@code eval} method |
| * does not suit, {@code null} is returned. |
| * |
| * @param method method that is used to implement the function |
| * @return created {@link Function} or null |
| */ |
| public static Function create(Method method) { |
| if (!Modifier.isStatic(method.getModifiers())) { |
| Class clazz = method.getDeclaringClass(); |
| if (!classHasPublicZeroArgsConstructor(clazz)) { |
| throw RESOURCE.requireDefaultConstructor(clazz.getName()).ex(); |
| } |
| } |
| if (method.getExceptionTypes().length != 0) { |
| throw new RuntimeException(method.getName() + " must not throw checked exception"); |
| } |
| |
| CallImplementor implementor = createImplementor(method); |
| return new ScalarFunctionImpl(method, implementor); |
| } |
| |
| @Override |
| public RelDataType getReturnType(RelDataTypeFactory typeFactory) { |
| return CalciteUtils.sqlTypeWithAutoCast(typeFactory, method.getReturnType()); |
| } |
| |
| @Override |
| public CallImplementor getImplementor() { |
| return implementor; |
| } |
| |
| private static CallImplementor createImplementor(final Method method) { |
| final NullPolicy nullPolicy = getNullPolicy(method); |
| return RexImpTable.createImplementor( |
| new ReflectiveCallNotNullImplementor(method), nullPolicy, false); |
| } |
| |
| private static NullPolicy getNullPolicy(Method m) { |
| if (m.getAnnotation(Strict.class) != null) { |
| return NullPolicy.STRICT; |
| } else if (m.getAnnotation(SemiStrict.class) != null) { |
| return NullPolicy.SEMI_STRICT; |
| } else if (m.getDeclaringClass().getAnnotation(Strict.class) != null) { |
| return NullPolicy.STRICT; |
| } else if (m.getDeclaringClass().getAnnotation(SemiStrict.class) != null) { |
| return NullPolicy.SEMI_STRICT; |
| } else { |
| return NullPolicy.NONE; |
| } |
| } |
| |
| public RelDataType getReturnType(RelDataTypeFactory typeFactory, SqlOperatorBinding opBinding) { |
| // Strict and semi-strict functions can return null even if their Java |
| // functions return a primitive type. Because when one of their arguments |
| // is null, they won't even be called. |
| final RelDataType returnType = getReturnType(typeFactory); |
| switch (getNullPolicy(method)) { |
| case STRICT: |
| for (RelDataType type : opBinding.collectOperandTypes()) { |
| if (type.isNullable()) { |
| return typeFactory.createTypeWithNullability(returnType, true); |
| } |
| } |
| break; |
| case SEMI_STRICT: |
| return typeFactory.createTypeWithNullability(returnType, true); |
| default: |
| break; |
| } |
| return returnType; |
| } |
| |
| /** |
| * Verifies if given class has public constructor with zero arguments. |
| * |
| * @param clazz class to verify |
| * @return true if given class has public constructor with zero arguments |
| */ |
| static boolean classHasPublicZeroArgsConstructor(Class<?> clazz) { |
| for (Constructor<?> constructor : clazz.getConstructors()) { |
| if (constructor.getParameterTypes().length == 0 |
| && Modifier.isPublic(constructor.getModifiers())) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* |
| * Finds a method in a given class by name. |
| * @param clazz class to search method in |
| * @param name name of the method to find |
| * @return the first method with matching name or null when no method found |
| */ |
| static Method findMethod(Class<?> clazz, String name) { |
| for (Method method : clazz.getMethods()) { |
| if (method.getName().equals(name) && !method.isBridge()) { |
| return method; |
| } |
| } |
| return null; |
| } |
| } |
| |
| // End ScalarFunctionImpl.java |