| /* |
| * 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.drill.exec.planner; |
| |
| import java.util.List; |
| import java.util.Map; |
| import org.apache.calcite.rel.type.RelDataType; |
| import org.apache.calcite.rex.RexInputRef; |
| import org.apache.calcite.rex.RexNode; |
| import org.apache.drill.common.expression.SchemaPath; |
| |
| public class StarColumnHelper { |
| |
| public final static String PREFIX_DELIMITER = "\u00a6\u00a6"; |
| |
| public final static String PREFIXED_STAR_COLUMN = PREFIX_DELIMITER + SchemaPath.DYNAMIC_STAR; |
| |
| public static boolean containsStarColumn(RelDataType type) { |
| if (! type.isStruct()) { |
| return false; |
| } |
| |
| List<String> fieldNames = type.getFieldNames(); |
| |
| for (String fieldName : fieldNames) { |
| if (SchemaPath.DYNAMIC_STAR.equals(fieldName)) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| public static boolean containsStarColumnInProject(RelDataType inputRowType, List<RexNode> projExprs) { |
| if (!inputRowType.isStruct()) { |
| return false; |
| } |
| |
| for (RexNode expr : projExprs) { |
| if (expr instanceof RexInputRef) { |
| String name = inputRowType.getFieldNames().get(((RexInputRef) expr).getIndex()); |
| |
| if (SchemaPath.DYNAMIC_STAR.equals(name)) { |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| public static boolean isPrefixedStarColumn(String fieldName) { |
| return fieldName.indexOf(PREFIXED_STAR_COLUMN) > 0; // the delimiter * starts at none-zero position. |
| } |
| |
| public static boolean isNonPrefixedStarColumn(String fieldName) { |
| return SchemaPath.DYNAMIC_STAR.equals(fieldName); |
| } |
| |
| public static boolean isStarColumn(String fieldName) { |
| return isPrefixedStarColumn(fieldName) || isNonPrefixedStarColumn(fieldName); |
| } |
| |
| // Expression in some sense is similar to regular columns. Expression (i.e. C1 + C2 + 10) is not |
| // associated with an alias, the project will have (C1 + C2 + 10) --> f1, column "f1" could be |
| // viewed as a regular column, and does not require prefix. If user put an alias, then, |
| // the project will have (C1 + C2 + 10) -> alias. |
| public static boolean isRegularColumnOrExp(String fieldName) { |
| return ! isStarColumn(fieldName); |
| } |
| |
| public static String extractStarColumnPrefix(String fieldName) { |
| |
| assert (isPrefixedStarColumn(fieldName)); |
| |
| return fieldName.substring(0, fieldName.indexOf(PREFIXED_STAR_COLUMN)); |
| } |
| |
| public static String extractColumnPrefix(String fieldName) { |
| if (fieldName.indexOf(PREFIX_DELIMITER) >=0) { |
| return fieldName.substring(0, fieldName.indexOf(PREFIX_DELIMITER)); |
| } else { |
| return ""; |
| } |
| } |
| |
| // Given a set of prefixes, check if a regular column is subsumed by any of the prefixed star column in the set. |
| public static boolean subsumeColumn(Map<String, String> prefixMap, String fieldName) { |
| String prefix = extractColumnPrefix(fieldName); |
| |
| if (isRegularColumnOrExp(fieldName)) { |
| return false; // regular column or expression is not subsumed by any star column. |
| } else { |
| return prefixMap.containsKey(prefix) && ! fieldName.equals(prefixMap.get(prefix)); // t1*0 is subsumed by t1*. |
| } |
| } |
| |
| } |