exec/java-exec/src/main/java/org/apache/drill/exec/planner/common/DrillRelOptUtil.java


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/**
 * 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.common;

import java.util.List;

import org.eigenbase.reltype.RelDataType;
import org.eigenbase.reltype.RelDataTypeField;
import org.eigenbase.sql.type.SqlTypeName;
import org.eigenbase.util.Pair;

/**
 * Utility class that is a subset of the RelOptUtil class and is a placeholder for Drill specific 
 * static methods that are needed during either logical or physical planning.
 */
public abstract class DrillRelOptUtil {

  // Similar to RelOptUtil.areRowTypesEqual() with the additional check for allowSubstring
  public static boolean areRowTypesEqual(
      RelDataType rowType1,
      RelDataType rowType2,
      boolean compareNames, 
      boolean allowSubstring) {
    if (rowType1 == rowType2) {
      return true;
    }
    if (compareNames) {
      // if types are not identity-equal, then either the names or
      // the types must be different
      return false;
    }
    if (rowType2.getFieldCount() != rowType1.getFieldCount()) {
      return false;
    }
    final List<RelDataTypeField> f1 = rowType1.getFieldList();
    final List<RelDataTypeField> f2 = rowType2.getFieldList();
    for (Pair<RelDataTypeField, RelDataTypeField> pair : Pair.zip(f1, f2)) {
      final RelDataType type1 = pair.left.getType();
      final RelDataType type2 = pair.right.getType();
      // If one of the types is ANY comparison should succeed
      if (type1.getSqlTypeName() == SqlTypeName.ANY
        || type2.getSqlTypeName() == SqlTypeName.ANY) {
        continue;
      }
      if (!type1.equals(type2)) {
        if (allowSubstring 
            && (type1.getSqlTypeName() == SqlTypeName.CHAR && type2.getSqlTypeName() == SqlTypeName.CHAR) 
            && (type1.getPrecision() <= type2.getPrecision())) {
          return true;
        }           
        return false;
      }
    }
    return true;
  }
}