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.enumerable;
  
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.rel.core.AggregateCall;
  
  import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  
  import java.util.List;
  
  /**
   * Represents internal state when implementing aggregate functions.
   */
  public class AggImpState {
    public final int aggIdx;
    public final AggregateCall call;
    public final AggImplementor implementor;
    public @MonotonicNonNull AggContext context;
    public @MonotonicNonNull Expression result;
    public @MonotonicNonNull List<Expression> state;
    public @MonotonicNonNull Expression accumulatorAdder;
  
    public AggImpState(int aggIdx, AggregateCall call, boolean windowContext) {
      this.aggIdx = aggIdx;
      this.call = call;
      AggImplementor implementor = RexImpTable.INSTANCE.get(call.getAggregation(), windowContext);
      if (implementor == null) {
        throw new IllegalArgumentException(
            "Unable to get aggregate implementation for aggregate "
            + call.getAggregation()
            + (windowContext ? " in window context" : ""));
      }
      this.implementor = implementor;
    }
  
    @Override public String toString() {
      return "AggImpState{aggIdx=" + aggIdx + ", call=" + call
          + ", implementor=" + implementor + "}";
    }
  }
  