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.DataContext;
  import org.apache.calcite.interpreter.BindableConvention;
  import org.apache.calcite.interpreter.BindableRel;
  import org.apache.calcite.interpreter.Node;
  import org.apache.calcite.interpreter.Row;
  import org.apache.calcite.interpreter.Sink;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.linq4j.Enumerator;
  import org.apache.calcite.plan.ConventionTraitDef;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.convert.ConverterImpl;
  import org.apache.calcite.rel.convert.ConverterRule;
  import org.apache.calcite.runtime.ArrayBindable;
  import org.apache.calcite.runtime.Bindable;
  
  import com.google.common.collect.ImmutableMap;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Relational expression that converts an enumerable input to interpretable
   * calling convention.
   *
   * @see org.apache.calcite.adapter.enumerable.EnumerableConvention
   * @see org.apache.calcite.interpreter.BindableConvention
   */
  public class EnumerableBindable extends ConverterImpl implements BindableRel {
    protected EnumerableBindable(RelOptCluster cluster, RelNode input) {
      super(cluster, ConventionTraitDef.INSTANCE,
          cluster.traitSetOf(BindableConvention.INSTANCE), input);
    }
  
    @Override public EnumerableBindable copy(RelTraitSet traitSet,
        List<RelNode> inputs) {
      return new EnumerableBindable(getCluster(), sole(inputs));
    }
  
    @Override public Class<Object[]> getElementType() {
      return Object[].class;
    }
  
    @Override public Enumerable<@Nullable Object[]> bind(DataContext dataContext) {
      final ImmutableMap<String, Object> map = ImmutableMap.of();
      final Bindable bindable =
          EnumerableInterpretable.toBindable(map, null,
              (EnumerableRel) getInput(), EnumerableRel.Prefer.ARRAY);
      final ArrayBindable arrayBindable = EnumerableInterpretable.box(bindable);
      return arrayBindable.bind(dataContext);
    }
  
    @Override public Node implement(final InterpreterImplementor implementor) {
      return () -> {
        final Sink sink =
            requireNonNull(implementor.relSinks.get(EnumerableBindable.this),
                () -> "relSinks.get is null for " + EnumerableBindable.this).get(0);
        final Enumerable<@Nullable Object[]> enumerable = bind(implementor.dataContext);
        final Enumerator<@Nullable Object[]> enumerator = enumerable.enumerator();
        while (enumerator.moveNext()) {
          sink.send(Row.asCopy(enumerator.current()));
        }
      };
    }
  
    /**
     * Rule that converts any enumerable relational expression to bindable.
     *
     * @see EnumerableRules#TO_BINDABLE
     */
    public static class EnumerableToBindableConverterRule extends ConverterRule {
      /** Default configuration. */
      public static final Config DEFAULT_CONFIG = Config.INSTANCE
          .withConversion(EnumerableRel.class,
              EnumerableConvention.INSTANCE, BindableConvention.INSTANCE,
              "EnumerableToBindableConverterRule")
          .withRuleFactory(EnumerableToBindableConverterRule::new);
  
      protected EnumerableToBindableConverterRule(Config config) {
        super(config);
      }
  
      @Override public RelNode convert(RelNode rel) {
        return new EnumerableBindable(rel.getCluster(), rel);
      }
    }
  }
  