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.metadata;
  
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Exchange;
  import org.apache.calcite.rel.core.TableScan;
  import org.apache.calcite.rel.core.Values;
  
  /**
   * Default implementations of the
   * {@link org.apache.calcite.rel.metadata.BuiltInMetadata.Parallelism}
   * metadata provider for the standard logical algebra.
   *
   * @see org.apache.calcite.rel.metadata.RelMetadataQuery#isPhaseTransition
   * @see org.apache.calcite.rel.metadata.RelMetadataQuery#splitCount
   */
  public class RelMdParallelism
      implements MetadataHandler<BuiltInMetadata.Parallelism> {
    /** Source for
     * {@link org.apache.calcite.rel.metadata.BuiltInMetadata.Parallelism}. */
    public static final RelMetadataProvider SOURCE =
        ReflectiveRelMetadataProvider.reflectiveSource(new RelMdParallelism(),
            BuiltInMetadata.Parallelism.Handler.class);
  
    //~ Constructors -----------------------------------------------------------
  
    protected RelMdParallelism() {}
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public MetadataDef<BuiltInMetadata.Parallelism> getDef() {
      return BuiltInMetadata.Parallelism.DEF;
    }
  
    /** Catch-all implementation for
     * {@link BuiltInMetadata.Parallelism#isPhaseTransition()},
     * invoked using reflection.
     *
     * @see org.apache.calcite.rel.metadata.RelMetadataQuery#isPhaseTransition
     */
    public Boolean isPhaseTransition(RelNode rel, RelMetadataQuery mq) {
      return false;
    }
  
    public Boolean isPhaseTransition(TableScan rel, RelMetadataQuery mq) {
      final BuiltInMetadata.Parallelism.Handler handler =
          rel.getTable().unwrap(BuiltInMetadata.Parallelism.Handler.class);
      if (handler != null) {
        return handler.isPhaseTransition(rel, mq);
      }
      return true;
    }
  
    public Boolean isPhaseTransition(Values rel, RelMetadataQuery mq) {
      return true;
    }
  
    public Boolean isPhaseTransition(Exchange rel, RelMetadataQuery mq) {
      return true;
    }
  
    /** Catch-all implementation for
     * {@link BuiltInMetadata.Parallelism#splitCount()},
     * invoked using reflection.
     *
     * @see org.apache.calcite.rel.metadata.RelMetadataQuery#splitCount
     */
    public Integer splitCount(RelNode rel, RelMetadataQuery mq) {
      return 1;
    }
  }
  