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.rel.mutable;
  
  import org.apache.calcite.rel.RelNode;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.List;
  
  /** Abstract base class for implementations of {@link MutableRel} that have
   * no inputs. */
  abstract class MutableLeafRel extends MutableRel {
    protected final RelNode rel;
  
    protected MutableLeafRel(MutableRelType type, RelNode rel) {
      super(rel.getCluster(), rel.getRowType(), type);
      this.rel = rel;
    }
  
    @Override public void setInput(int ordinalInParent, MutableRel input) {
      throw new IllegalArgumentException();
    }
  
    @Override public List<MutableRel> getInputs() {
      return ImmutableList.of();
    }
  
    @Override public void childrenAccept(MutableRelVisitor visitor) {
      // no children - nothing to do
    }
  }
  