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.cassandra.cql3.selection;
  
  import java.nio.ByteBuffer;
  import java.util.List;
  
  import org.apache.cassandra.cql3.functions.Function;
  import org.apache.cassandra.cql3.functions.ScalarFunction;
  import org.apache.cassandra.transport.ProtocolVersion;
  
  import static org.apache.cassandra.cql3.statements.RequestValidations.checkTrue;
  
  final class ScalarFunctionSelector extends AbstractFunctionSelector<ScalarFunction>
  {
      static final SelectorDeserializer deserializer = new AbstractFunctionSelectorDeserializer()
      {
          @Override
          protected Selector newFunctionSelector(ProtocolVersion version, Function function, List<Selector> argSelectors)
          {
              return new ScalarFunctionSelector(version, function, argSelectors);
          }
      };
  
      public void addInput(InputRow input)
      {
          for (int i = 0, m = argSelectors.size(); i < m; i++)
          {
              Selector s = argSelectors.get(i);
              s.addInput(input);
          }
      }
  
      public void reset()
      {
      }
  
      public ByteBuffer getOutput(ProtocolVersion protocolVersion)
      {
          for (int i = 0, m = argSelectors.size(); i < m; i++)
          {
              Selector s = argSelectors.get(i);
              setArg(i, s.getOutput(protocolVersion));
              s.reset();
          }
          return fun.execute(args());
      }
  
      @Override
      public void validateForGroupBy()
      {
          checkTrue(fun.isMonotonic(), "Only monotonic functions are supported in the GROUP BY clause. Got: %s ", fun);
          for (int i = 0, m = argSelectors.size(); i < m; i++)
              argSelectors.get(i).validateForGroupBy();
      }
  
      ScalarFunctionSelector(ProtocolVersion version, Function fun, List<Selector> argSelectors)
      {
          super(Kind.SCALAR_FUNCTION_SELECTOR, version, (ScalarFunction) fun, argSelectors);
      }
  }
  