twalthr commented on a change in pull request #11081: [FLINK-16033][table-api] Introduced Java Table API Expression DSL URL: https://github.com/apache/flink/pull/11081#discussion_r380077918
########## File path: flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/api/internal/BaseExpressions.java ########## @@ -0,0 +1,1146 @@ +/* + * 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.api.internal; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.api.common.typeinfo.SqlTimeTypeInfo; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.expressions.Expression; +import org.apache.flink.table.expressions.TimeIntervalUnit; +import org.apache.flink.table.expressions.utils.ApiExpressionUtils; +import org.apache.flink.table.functions.BuiltInFunctionDefinitions; +import org.apache.flink.table.types.DataType; + +import java.util.Arrays; +import java.util.stream.Stream; + +import static org.apache.flink.table.expressions.utils.ApiExpressionUtils.objectToExpression; +import static org.apache.flink.table.expressions.utils.ApiExpressionUtils.tableRef; +import static org.apache.flink.table.expressions.utils.ApiExpressionUtils.typeLiteral; +import static org.apache.flink.table.expressions.utils.ApiExpressionUtils.unresolvedCall; +import static org.apache.flink.table.expressions.utils.ApiExpressionUtils.valueLiteral; +import static org.apache.flink.table.types.utils.TypeConversions.fromLegacyInfoToDataType; +//CHECKSTYLE.OFF: AvoidStarImport|ImportOrder +import static org.apache.flink.table.functions.BuiltInFunctionDefinitions.*; +//CHECKSTYLE.ON: AvoidStarImport|ImportOrder + +/** + * These are Java and Scala common operations that can be used to construct an {@link Expression} AST for + * expression operations. + */ +@PublicEvolving +public abstract class BaseExpressions<InT, OutT> { + protected abstract Expression toExpr(); + + protected abstract OutT toApiSpecificExpression(Expression expression); + + /** + * Specifies a name for an expression i.e. a field. + * + * @param name name for one field + * @param extraNames additional names if the expression expands to multiple fields + * @return field with an alias + */ + public OutT as(String name, String... extraNames) { + return toApiSpecificExpression(ApiExpressionUtils.unresolvedCall( + BuiltInFunctionDefinitions.AS, + Stream.concat( + Stream.of(toExpr(), ApiExpressionUtils.valueLiteral(name)), + Stream.of(extraNames).map(ApiExpressionUtils::valueLiteral) + ).toArray(Expression[]::new))); + } + + /** + * Boolean AND in three-valued logic. + */ + public OutT and(InT other) { + return toApiSpecificExpression(unresolvedCall(AND, toExpr(), objectToExpression(other))); + } + + /** + * Boolean OR in three-valued logic. + */ + public OutT or(InT other) { + return toApiSpecificExpression(unresolvedCall(OR, toExpr(), objectToExpression(other))); + } + + /** + * Greater than. + */ + public OutT isGreater(InT other) { + return toApiSpecificExpression(unresolvedCall(GREATER_THAN, toExpr(), objectToExpression(other))); + } + + /** + * Greater than or equal. + */ + public OutT isGreaterOrEqual(InT other) { + return toApiSpecificExpression(unresolvedCall(GREATER_THAN_OR_EQUAL, toExpr(), objectToExpression(other))); + } + + /** + * Less than. + */ + public OutT isLess(InT other) { + return toApiSpecificExpression(unresolvedCall(LESS_THAN, toExpr(), objectToExpression(other))); + } + + /** + * Less than or equal. + */ + public OutT isLessOrEqual(InT other) { + return toApiSpecificExpression(unresolvedCall(LESS_THAN_OR_EQUAL, toExpr(), objectToExpression(other))); + } + + /** + * Equals. + */ + public OutT isEqual(InT other) { + return toApiSpecificExpression(unresolvedCall(EQUALS, toExpr(), objectToExpression(other))); + } + + /** + * Not equal. + */ + public OutT isNotEqual(InT other) { + return toApiSpecificExpression(unresolvedCall(NOT_EQUALS, toExpr(), objectToExpression(other))); + } + + /** + * Returns left plus right. + */ + public OutT plus(InT other) { + return toApiSpecificExpression(unresolvedCall(PLUS, toExpr(), objectToExpression(other))); + } + + /** + * Returns left minus right. + */ + public OutT minus(InT other) { + return toApiSpecificExpression(unresolvedCall(MINUS, toExpr(), objectToExpression(other))); + } + + /** + * Returns left divided by right. + */ + public OutT dividedBy(InT other) { + return toApiSpecificExpression(unresolvedCall(DIVIDE, toExpr(), objectToExpression(other))); + } + + /** + * Returns left multiplied by right. + */ + public OutT multipliedBy(InT other) { + return toApiSpecificExpression(unresolvedCall(TIMES, toExpr(), objectToExpression(other))); + } + + /** + * Returns true if the given expression is between lowerBound and upperBound (both inclusive). + * False otherwise. The parameters must be numeric types or identical comparable types. + * + * @param lowerBound numeric or comparable expression + * @param upperBound numeric or comparable expression + * @return boolean or null + */ + public OutT between(InT lowerBound, InT upperBound) { + return toApiSpecificExpression(unresolvedCall( + BETWEEN, + toExpr(), + objectToExpression(lowerBound), + objectToExpression(upperBound))); + } + + /** + * Returns true if the given expression is not between lowerBound and upperBound (both + * inclusive). False otherwise. The parameters must be numeric types or identical + * comparable types. + * + * @param lowerBound numeric or comparable expression + * @param upperBound numeric or comparable expression + * @return boolean or null + */ + public OutT notBetween(InT lowerBound, InT upperBound) { + return toApiSpecificExpression(unresolvedCall( + NOT_BETWEEN, + toExpr(), + objectToExpression(lowerBound), + objectToExpression(upperBound))); + } + + /** + * Returns true if the given expression is null. + */ + public OutT isNull() { + return toApiSpecificExpression(unresolvedCall(IS_NULL, toExpr())); + } + + /** + * Returns true if the given expression is not null. + */ + public OutT isNotNull() { + return toApiSpecificExpression(unresolvedCall(IS_NOT_NULL, toExpr())); + } + + /** + * Returns true if given boolean expression is true. False otherwise (for null and false). + */ + public OutT isTrue() { + return toApiSpecificExpression(unresolvedCall(IS_TRUE, toExpr())); + } + + /** + * Returns true if given boolean expression is false. False otherwise (for null and true). + */ + public OutT isFalse() { + return toApiSpecificExpression(unresolvedCall(IS_FALSE, toExpr())); + } + + /** + * Returns true if given boolean expression is not true (for null and false). False otherwise. + */ + public OutT isNotTrue() { + return toApiSpecificExpression(unresolvedCall(IS_NOT_TRUE, toExpr())); + } + + /** + * Returns true if given boolean expression is not false (for null and true). False otherwise. + */ + public OutT isNotFalse() { + return toApiSpecificExpression(unresolvedCall(IS_NOT_FALSE, toExpr())); + } + + /** + * Similar to a SQL distinct aggregation clause such as COUNT(DISTINCT a), declares that an + * aggregation function is only applied on distinct input values. + * + * <p>For example: + * <pre> + * {@code + * orders + * .groupBy('a) + * .select('a, 'b.sum.distinct as 'd) + * } + * </pre> + */ + public OutT distinct() { + return toApiSpecificExpression(unresolvedCall(DISTINCT, toExpr())); + } + + /** + * Returns the sum of the numeric field across all input values. + * If all values are null, null is returned. + */ + public OutT sum() { + return toApiSpecificExpression(unresolvedCall(SUM, toExpr())); + } + + /** + * Returns the sum of the numeric field across all input values. + * If all values are null, 0 is returned. + */ + public OutT sum0() { + return toApiSpecificExpression(unresolvedCall(SUM0, toExpr())); + } + + /** + * Returns the minimum value of field across all input values. + */ + public OutT min() { + return toApiSpecificExpression(unresolvedCall(MIN, toExpr())); + } + + /** + * Returns the maximum value of field across all input values. + */ + public OutT max() { + return toApiSpecificExpression(unresolvedCall(MAX, toExpr())); + } + + /** + * Returns the number of input rows for which the field is not null. + */ + public OutT count() { + return toApiSpecificExpression(unresolvedCall(COUNT, toExpr())); + } + + /** + * Returns the average (arithmetic mean) of the numeric field across all input values. + */ + public OutT avg() { + return toApiSpecificExpression(unresolvedCall(AVG, toExpr())); + } + + /** + * Returns the population standard deviation of an expression (the square root of varPop()). + */ + public OutT stddevPop() { + return toApiSpecificExpression(unresolvedCall(STDDEV_POP, toExpr())); + } + + /** + * Returns the sample standard deviation of an expression (the square root of varSamp()). + */ + public OutT stddevSamp() { + return toApiSpecificExpression(unresolvedCall(STDDEV_SAMP, toExpr())); + } + + /** + * Returns the population standard variance of an expression. + */ + public OutT varPop() { + return toApiSpecificExpression(unresolvedCall(VAR_POP, toExpr())); + } + + /** + * Returns the sample variance of a given expression. + */ + public OutT varSamp() { + return toApiSpecificExpression(unresolvedCall(VAR_SAMP, toExpr())); + } + + /** + * Returns multiset aggregate of a given expression. + */ + public OutT collect() { + return toApiSpecificExpression(unresolvedCall(COLLECT, toExpr())); + } + + /** + * Converts a value to a given data type. + * + * <p>e.g. "42".cast(DataTypes.INT()) leads to 42. + * + * @return casted expression + */ + public OutT cast(DataType toType) { + return toApiSpecificExpression(unresolvedCall(CAST, toExpr(), typeLiteral(toType))); + } + + /** + * @deprecated This method will be removed in future versions as it uses the old type system. It + * is recommended to use {@link #cast(DataType)} instead which uses the new type system Review comment: nit: indent ---------------------------------------------------------------- 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
