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.beam.sdk.extensions.sql.impl.utils;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexFieldAccess;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexInputRef;
  
  /** SerializableRexFieldAccess. */
  public class SerializableRexFieldAccess extends SerializableRexNode {
    private List<Integer> indexes = new ArrayList<>();
  
    public SerializableRexFieldAccess(RexFieldAccess rexFieldAccess) {
      indexes.add(rexFieldAccess.getField().getIndex());
      RexFieldAccess curr = rexFieldAccess;
      while (curr.getReferenceExpr() instanceof RexFieldAccess) {
        curr = (RexFieldAccess) curr.getReferenceExpr();
        indexes.add(rexFieldAccess.getField().getIndex());
      }
  
      // curr.getReferenceExpr() is not a RexFieldAccess. Check if it is RexInputRef, which is only
      // allowed RexNode type in RexFieldAccess.
      if (!(curr.getReferenceExpr() instanceof RexInputRef)) {
        throw new UnsupportedOperationException(
            "Does not support " + curr.getReferenceExpr().getType());
      }
  
      // curr.getReferenceExpr() is a RexInputRef.
      RexInputRef inputRef = (RexInputRef) curr.getReferenceExpr();
      indexes.add(inputRef.getIndex());
  
      Collections.reverse(indexes);
    }
  
    public List<Integer> getIndexes() {
      return indexes;
    }
  }
  