/**
 * 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.pinot.core.startree.v2;

import org.apache.pinot.common.function.AggregationFunctionType;


public class AggregationFunctionColumnPair {
  public static final String DELIMITER = "__";
  public static final String STAR = "*";
  public static final AggregationFunctionColumnPair COUNT_STAR =
      new AggregationFunctionColumnPair(AggregationFunctionType.COUNT, STAR);

  private final AggregationFunctionType _functionType;
  private final String _column;

  public AggregationFunctionColumnPair(AggregationFunctionType functionType, String column) {
    _functionType = functionType;
    if (functionType == AggregationFunctionType.COUNT) {
      _column = STAR;
    } else {
      _column = column;
    }
  }

  public AggregationFunctionType getFunctionType() {
    return _functionType;
  }

  public String getColumn() {
    return _column;
  }

  public String toColumnName() {
    return toColumnName(_functionType, _column);
  }

  public static String toColumnName(AggregationFunctionType functionType, String column) {
    return functionType.getName() + DELIMITER + column;
  }

  public static AggregationFunctionColumnPair fromColumnName(String columnName) {
    String[] parts = columnName.split(DELIMITER, 2);
    AggregationFunctionType functionType = AggregationFunctionType.valueOf(parts[0].toUpperCase());
    if (functionType == AggregationFunctionType.COUNT) {
      return COUNT_STAR;
    } else {
      return new AggregationFunctionColumnPair(functionType, parts[1]);
    }
  }

  @Override
  public int hashCode() {
    return 31 * _functionType.hashCode() + _column.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj instanceof AggregationFunctionColumnPair) {
      AggregationFunctionColumnPair anotherPair = (AggregationFunctionColumnPair) obj;
      return _functionType == anotherPair._functionType && _column.equals(anotherPair._column);
    }
    return false;
  }
}

@@ -2794,11 +2794,84 @@
 lse;%0A  %7D
+%0A%0A  @Override%0A  public String toString() %7B%0A    return toColumnName();%0A  %7D
 %0A%7D%0A

Add toString() to AggregationFunctionColumnPair (#6077)