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.linq4j.Ord;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.util.Util;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /** Base Class for relations with three or more inputs. */
  abstract class MutableMultiRel extends MutableRel {
    protected final List<MutableRel> inputs;
  
    @SuppressWarnings("initialization.invalid.field.write.initialized")
    protected MutableMultiRel(RelOptCluster cluster,
        RelDataType rowType, MutableRelType type, List<MutableRel> inputs) {
      super(cluster, rowType, type);
      this.inputs = new ArrayList<>(inputs);
      for (Ord<MutableRel> input : Ord.zip(inputs)) {
        input.e.parent = this;
        input.e.ordinalInParent = input.i;
      }
    }
  
    @Override public void setInput(int ordinalInParent, MutableRel input) {
      inputs.set(ordinalInParent, input);
      if (input != null) {
        input.parent = this;
        input.ordinalInParent = ordinalInParent;
      }
    }
  
    @Override public List<MutableRel> getInputs() {
      return inputs;
    }
  
    @Override public void childrenAccept(MutableRelVisitor visitor) {
      for (MutableRel input : inputs) {
        visitor.visit(input);
      }
    }
  
    protected List<MutableRel> cloneChildren() {
      return Util.transform(inputs, MutableRel::clone);
    }
  }
  