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 com.google.common.collect.ImmutableList;
  
  /**
   * DefaultRelMetadataProvider supplies a default implementation of the
   * {@link RelMetadataProvider} interface. It provides generic formulas and
   * derivation rules for the standard logical algebra; coverage corresponds to
   * the methods declared in {@link RelMetadataQuery}.
   */
  public class DefaultRelMetadataProvider extends ChainedRelMetadataProvider {
    public static final DefaultRelMetadataProvider INSTANCE =
        new DefaultRelMetadataProvider();
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a new default provider. This provider defines "catch-all"
     * handlers for generic RelNodes, so it should always be given lowest
     * priority when chaining.
     *
     * <p>Use this constructor only from a sub-class. Otherwise use the singleton
     * instance, {@link #INSTANCE}.
     */
    protected DefaultRelMetadataProvider() {
      super(
          ImmutableList.of(
              RelMdPercentageOriginalRows.SOURCE,
              RelMdColumnOrigins.SOURCE,
              RelMdExpressionLineage.SOURCE,
              RelMdTableReferences.SOURCE,
              RelMdNodeTypes.SOURCE,
              RelMdRowCount.SOURCE,
              RelMdMaxRowCount.SOURCE,
              RelMdMinRowCount.SOURCE,
              RelMdUniqueKeys.SOURCE,
              RelMdColumnUniqueness.SOURCE,
              RelMdPopulationSize.SOURCE,
              RelMdSize.SOURCE,
              RelMdParallelism.SOURCE,
              RelMdDistribution.SOURCE,
              RelMdLowerBoundCost.SOURCE,
              RelMdMeasure.SOURCE,
              RelMdMemory.SOURCE,
              RelMdDistinctRowCount.SOURCE,
              RelMdSelectivity.SOURCE,
              RelMdExplainVisibility.SOURCE,
              RelMdPredicates.SOURCE,
              RelMdAllPredicates.SOURCE,
              RelMdCollation.SOURCE,
              RelMdFunctionalDependency.SOURCE));
    }
  }
  