/* * 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.calcite.adapter.csv; import org.apache.calcite.DataContext; import org.apache.calcite.linq4j.AbstractEnumerable; import org.apache.calcite.linq4j.Enumerable; import org.apache.calcite.linq4j.Enumerator; import org.apache.calcite.rel.type.RelProtoDataType; import org.apache.calcite.rex.RexCall; import org.apache.calcite.rex.RexInputRef; import org.apache.calcite.rex.RexLiteral; import org.apache.calcite.rex.RexNode; import org.apache.calcite.schema.FilterableTable; import org.apache.calcite.sql.SqlKind; import org.apache.calcite.util.Source; import java.util.List; import java.util.concurrent.atomic.AtomicBoolean; /** * Table based on a CSV file that can implement simple filtering. * * <p>It implements the {@link FilterableTable} interface, so Calcite gets * data by calling the {@link #scan(DataContext, List)} method. */ public class CsvFilterableTable extends CsvTable implements FilterableTable { /** Creates a CsvFilterableTable. */ public CsvFilterableTable(Source source, RelProtoDataType protoRowType) { super(source, protoRowType); } public String toString() { return "CsvFilterableTable"; } public Enumerable<Object[]> scan(DataContext root, List<RexNode> filters) { final List<CsvFieldType> fieldTypes = getFieldTypes(root.getTypeFactory()); final String[] filterValues = new String[fieldTypes.size()]; filters.removeIf(filter -> addFilter(filter, filterValues)); final int[] fields = CsvEnumerator.identityList(fieldTypes.size()); final AtomicBoolean cancelFlag = DataContext.Variable.CANCEL_FLAG.get(root); return new AbstractEnumerable<Object[]>() { public Enumerator<Object[]> enumerator() { return new CsvEnumerator<>(source, cancelFlag, false, filterValues, new CsvEnumerator.ArrayRowConverter(fieldTypes, fields)); } }; } private boolean addFilter(RexNode filter, Object[] filterValues) { if (filter.isA(SqlKind.AND)) { // We cannot refine(remove) the operands of AND, // it will cause o.a.c.i.TableScanNode.createFilterable filters check failed. ((RexCall) filter).getOperands().forEach(subFilter -> addFilter(subFilter, filterValues)); } else if (filter.isA(SqlKind.EQUALS)) { final RexCall call = (RexCall) filter; RexNode left = call.getOperands().get(0); if (left.isA(SqlKind.CAST)) { left = ((RexCall) left).operands.get(0); } final RexNode right = call.getOperands().get(1); if (left instanceof RexInputRef && right instanceof RexLiteral) { final int index = ((RexInputRef) left).getIndex(); if (filterValues[index] == null) { filterValues[index] = ((RexLiteral) right).getValue2().toString(); return true; } } } return false; } }