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.Ord;
  import org.apache.calcite.linq4j.tree.BlockBuilder;
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.linq4j.tree.Expressions;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Intersect;
  import org.apache.calcite.util.BuiltInMethod;
  
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /** Implementation of {@link org.apache.calcite.rel.core.Intersect} in
   * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. */
  public class EnumerableIntersect extends Intersect implements EnumerableRel {
    public EnumerableIntersect(RelOptCluster cluster, RelTraitSet traitSet,
        List<RelNode> inputs, boolean all) {
      super(cluster, traitSet, inputs, all);
    }
  
    @Override public EnumerableIntersect copy(RelTraitSet traitSet, List<RelNode> inputs,
        boolean all) {
      return new EnumerableIntersect(getCluster(), traitSet, inputs, all);
    }
  
    @Override public Result implement(EnumerableRelImplementor implementor, Prefer pref) {
      final BlockBuilder builder = new BlockBuilder();
      Expression intersectExp = null;
      for (Ord<RelNode> ord : Ord.zip(inputs)) {
        EnumerableRel input = (EnumerableRel) ord.e;
        final Result result = implementor.visitChild(this, ord.i, input, pref);
        Expression childExp =
            builder.append(
                "child" + ord.i,
                result.block);
  
        if (intersectExp == null) {
          intersectExp = childExp;
        } else {
          intersectExp =
              Expressions.call(intersectExp,
                  BuiltInMethod.INTERSECT.method,
                  Expressions.list(childExp)
                      .appendIfNotNull(result.physType.comparer())
                      .append(Expressions.constant(all)));
        }
  
        // Once the first input has chosen its format, ask for the same for
        // other inputs.
        pref = pref.of(result.format);
      }
  
      builder.add(requireNonNull(intersectExp, "intersectExp"));
      final PhysType physType =
          PhysTypeImpl.of(
              implementor.getTypeFactory(),
              getRowType(),
              pref.prefer(JavaRowFormat.CUSTOM));
      return implementor.result(physType, builder.toBlock());
    }
  }
  