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.plan.RelOptCluster;
  import org.apache.calcite.rel.type.RelDataType;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.List;
  
  /** Mutable equivalent of {@link org.apache.calcite.rel.BiRel}. */
  abstract class MutableBiRel extends MutableRel {
    protected MutableRel left;
    protected MutableRel right;
  
    @SuppressWarnings("initialization.invalid.field.write.initialized")
    protected MutableBiRel(MutableRelType type, RelOptCluster cluster,
        RelDataType rowType, MutableRel left, MutableRel right) {
      super(cluster, rowType, type);
      this.left = left;
      left.parent = this;
      left.ordinalInParent = 0;
  
      this.right = right;
      right.parent = this;
      right.ordinalInParent = 1;
    }
  
    @Override public void setInput(int ordinalInParent, MutableRel input) {
      if (ordinalInParent > 1) {
        throw new IllegalArgumentException();
      }
      if (ordinalInParent == 0) {
        this.left = input;
      } else {
        this.right = input;
      }
      if (input != null) {
        input.parent = this;
        input.ordinalInParent = ordinalInParent;
      }
    }
  
    @Override public List<MutableRel> getInputs() {
      return ImmutableList.of(left, right);
    }
  
    public MutableRel getLeft() {
      return left;
    }
  
    public MutableRel getRight() {
      return right;
    }
  
    @Override public void childrenAccept(MutableRelVisitor visitor) {
  
      visitor.visit(left);
      visitor.visit(right);
    }
  }
  