processing/src/main/java/org/apache/druid/query/topn/LegacyTopNMetricSpec.java

/*
 * 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.druid.query.topn;

import com.fasterxml.jackson.annotation.JsonCreator;
import org.apache.druid.java.util.common.IAE;

import java.util.Map;

/**
 */
public class LegacyTopNMetricSpec extends NumericTopNMetricSpec
{
  private static String convertValue(Object metric)
  {
    final String retVal;

    if (metric instanceof String) {
      retVal = (String) metric;
    } else if (metric instanceof Map) {
      retVal = (String) ((Map) metric).get("metric");
    } else {
      throw new IAE("Unknown type[%s] for metric[%s]", metric.getClass(), metric);
    }

    return retVal;
  }

  @JsonCreator
  public LegacyTopNMetricSpec(Object metric)
  {
    super(convertValue(metric));
  }
}