openinx commented on a change in pull request #1893: URL: https://github.com/apache/iceberg/pull/1893#discussion_r551218250
########## File path: flink/src/main/java/org/apache/iceberg/flink/FlinkFilters.java ########## @@ -0,0 +1,270 @@ +/* + * 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.iceberg.flink; + +import java.time.Instant; +import java.time.LocalDate; +import java.time.LocalDateTime; +import java.time.LocalTime; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.function.BiFunction; +import java.util.regex.Matcher; +import java.util.regex.Pattern; +import java.util.stream.Collectors; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.table.expressions.CallExpression; +import org.apache.flink.table.expressions.FieldReferenceExpression; +import org.apache.flink.table.expressions.ResolvedExpression; +import org.apache.flink.table.expressions.ValueLiteralExpression; +import org.apache.flink.table.functions.BuiltInFunctionDefinitions; +import org.apache.flink.table.functions.FunctionDefinition; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.expressions.Expression.Operation; +import org.apache.iceberg.expressions.Expressions; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap; +import org.apache.iceberg.util.DateTimeUtil; +import org.apache.iceberg.util.NaNUtil; + +import static org.apache.iceberg.expressions.Expressions.isNaN; + +public class FlinkFilters { + private FlinkFilters() { + } + + private static final Pattern STARTS_WITH_PATTERN = Pattern.compile("([^%]+)%"); + + private static final Map<FunctionDefinition, Operation> FILTERS = ImmutableMap + .<FunctionDefinition, Operation>builder() + .put(BuiltInFunctionDefinitions.EQUALS, Operation.EQ) + .put(BuiltInFunctionDefinitions.NOT_EQUALS, Operation.NOT_EQ) + .put(BuiltInFunctionDefinitions.GREATER_THAN, Operation.GT) + .put(BuiltInFunctionDefinitions.GREATER_THAN_OR_EQUAL, Operation.GT_EQ) + .put(BuiltInFunctionDefinitions.LESS_THAN, Operation.LT) + .put(BuiltInFunctionDefinitions.LESS_THAN_OR_EQUAL, Operation.LT_EQ) + .put(BuiltInFunctionDefinitions.IN, Operation.IN) + .put(BuiltInFunctionDefinitions.IS_NULL, Operation.IS_NULL) + .put(BuiltInFunctionDefinitions.IS_NOT_NULL, Operation.NOT_NULL) + .put(BuiltInFunctionDefinitions.AND, Operation.AND) + .put(BuiltInFunctionDefinitions.OR, Operation.OR) + .put(BuiltInFunctionDefinitions.NOT, Operation.NOT) + .put(BuiltInFunctionDefinitions.LIKE, Operation.STARTS_WITH) + .build(); + + public static Optional<Expression> convert(org.apache.flink.table.expressions.Expression flinkExpression) { + if (flinkExpression == null || !(flinkExpression instanceof CallExpression)) { + return Optional.empty(); + } + + CallExpression call = (CallExpression) flinkExpression; + Operation op = FILTERS.get(call.getFunctionDefinition()); + if (op != null) { + switch (op) { + case IS_NULL: + Optional<String> name = toReference(getOnlyChild(call, FieldReferenceExpression.class).orElse(null)); + return name.map(Expressions::isNull); + + case NOT_NULL: + Optional<String> nameNotNull = toReference(getOnlyChild(call, FieldReferenceExpression.class).orElse(null)); + return nameNotNull.map(Expressions::notNull); + + case LT: + return convertComparisonExpression(Expressions::lessThan, call); + + case LT_EQ: + return convertComparisonExpression(Expressions::lessThanOrEqual, call); + + case GT: + return convertComparisonExpression(Expressions::greaterThan, call); + + case GT_EQ: + return convertComparisonExpression(Expressions::greaterThanOrEqual, call); + + case EQ: + return handleNaN(Expressions::equal, call); + + case NOT_EQ: + return handleNaN(Expressions::notEqual, call); + + case IN: + List<ResolvedExpression> args = call.getResolvedChildren(); + Optional<String> fieldName = toReference(args.get(0)); + List<ResolvedExpression> values = args.subList(1, args.size()); + + List<Object> inputValues = values.stream().filter(expression -> { + if (expression instanceof ValueLiteralExpression) { + return !((ValueLiteralExpression) expression).isNull(); + } + + return false; + }).map(expression -> { + Optional<Object> value = toLiteral(expression); + return value.get(); + }).collect(Collectors.toList()); + + return Optional.of(Expressions.in(fieldName.get(), inputValues)); + + case NOT: + Optional<Expression> child = convert(getOnlyChild(call, CallExpression.class).orElse(null)); + return child.map(Expressions::not); + + case AND: + return convertLogicExpression(Expressions::and, call); + + case OR: + return convertLogicExpression(Expressions::or, call); + + case STARTS_WITH: + return convertLike(call); + } + } + + return Optional.empty(); + } + + private static <T extends ResolvedExpression> Optional<T> getOnlyChild(CallExpression call, + Class<T> expectedChildClass) { + List<ResolvedExpression> children = call.getResolvedChildren(); + if (children.size() != 1) { + return Optional.empty(); + } + + ResolvedExpression child = children.get(0); + if (!expectedChildClass.isInstance(child)) { + return Optional.empty(); + } + + return Optional.of(expectedChildClass.cast(child)); + } + + private static Optional<Expression> convertLike(CallExpression call) { + Tuple2<String, Object> tuple2 = convertBinaryExpress(call); + if (tuple2 == null) { + return Optional.empty(); + } + + String pattern = tuple2.f1.toString(); + Matcher matcher = STARTS_WITH_PATTERN.matcher(pattern); + + // exclude special char of LIKE + // '_' is the wildcard of the SQL LIKE + if (!pattern.contains("_") && matcher.matches()) { + return Optional.of(Expressions.startsWith(tuple2.f0, matcher.group(1))); + } + + return Optional.empty(); + } + + private static Optional<Expression> convertLogicExpression(BiFunction<Expression, Expression, Expression> function, + CallExpression call) { + List<ResolvedExpression> args = call.getResolvedChildren(); + Optional<Expression> left = convert(args.get(0)); + Optional<Expression> right = convert(args.get(1)); + if (left.isPresent() && right.isPresent()) { + return Optional.of(function.apply(left.get(), right.get())); + } + + return Optional.empty(); + } + + private static Optional<Expression> convertComparisonExpression(BiFunction<String, Object, Expression> function, + CallExpression call) { + Tuple2<String, Object> tuple2 = convertBinaryExpress(call); + if (tuple2 != null) { + return Optional.of(function.apply(tuple2.f0, tuple2.f1)); Review comment: Pls consider the two cases: ```java Case.1 : a < 1; Case.2: 1 < a; ``` Here we `convertBinaryExpress` will parse the `tuple2` as `<a, 1>`. and the `function` will be `lessThan`. While in the actual the case.2 is totally different with case.1 because its meaning is : a is `greaterThan` 1 . That's why we introduced a reversed function in [here](https://github.com/generic-datalake/iceberg-poc/pull/2/files#diff-86160616589acf1dd526b10b73418a46fe60f9e5e5ab6946a4ea3c8f019542f5R65), for example, the `greaterThan`'s revered function is `lessThan`, the `lessThan`'s reversed function is `greaterThan`. If the case `1 < a` then we should call the reversed function here. ---------------------------------------------------------------- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
