content: /*
   * 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.druid;
  
  import org.apache.calcite.rel.core.AggregateCall;
  import org.apache.calcite.sql.SqlKind;
  
  /**
   * Stores information about available complex metrics in the Druid Adapter.
   */
  public class ComplexMetric {
  
    /** The underlying metric column that this complex metric represents. */
    private final String metricName;
  
    /** The type of this metric. */
    private final DruidType type;
  
    public ComplexMetric(String metricName, DruidType type) {
      validate(type);
      this.metricName = metricName;
      this.type = type;
    }
  
    private static void validate(DruidType type) {
      if (!type.isComplex()) {
        throw new IllegalArgumentException("Druid type: " + type + " is not complex");
      }
    }
  
    public String getMetricName() {
      return metricName;
    }
  
    public DruidType getDruidType() {
      return type;
    }
  
    public String getMetricType() {
      switch (type) {
      case HYPER_UNIQUE:
        return "hyperUnique";
      case THETA_SKETCH:
        return "thetaSketch";
      default:
        throw new AssertionError("Type: "
                + type + " does not have an associated metric type");
      }
    }
  
    /**
     * Returns true if and only if this <code>ComplexMetric</code>
     * can be used in the given {@link AggregateCall}.
     * */
    public boolean canBeUsed(AggregateCall call) {
      switch (type) {
      case HYPER_UNIQUE:
      case THETA_SKETCH:
        return call != null
              && call.getAggregation().getKind() == SqlKind.COUNT
              && call.isDistinct();
      default:
        return false;
      }
    }
  }
  