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.logical;
  
  import org.apache.calcite.plan.Convention;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelCollationTraitDef;
  import org.apache.calcite.rel.RelDistributionTraitDef;
  import org.apache.calcite.rel.RelInput;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Snapshot;
  import org.apache.calcite.rel.hint.RelHint;
  import org.apache.calcite.rel.metadata.RelMdCollation;
  import org.apache.calcite.rel.metadata.RelMdDistribution;
  import org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.calcite.rex.RexNode;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.List;
  
  /**
   * Sub-class of {@link org.apache.calcite.rel.core.Snapshot}
   * not targeted at any particular engine or calling convention.
   */
  public class LogicalSnapshot extends Snapshot {
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a LogicalSnapshot by parsing serialized output.
     */
    public LogicalSnapshot(RelInput input) {
      super(input);
    }
  
    /**
     * Creates a LogicalSnapshot.
     *
     * <p>Use {@link #create} unless you know what you're doing.
     *
     * @param cluster   Cluster that this relational expression belongs to
     * @param traitSet  The traits of this relational expression
     * @param hints     Hints for this node
     * @param input     Input relational expression
     * @param period    Timestamp expression which as the table was at the given
     *                  time in the past
     */
    public LogicalSnapshot(RelOptCluster cluster, RelTraitSet traitSet, List<RelHint> hints,
        RelNode input, RexNode period) {
      super(cluster, traitSet, hints, input, period);
    }
  
    /**
     * Creates a LogicalSnapshot.
     *
     * <p>Use {@link #create} unless you know what you're doing.
     *
     * @param cluster   Cluster that this relational expression belongs to
     * @param traitSet  The traits of this relational expression
     * @param input     Input relational expression
     * @param period    Timestamp expression which as the table was at the given
     *                  time in the past
     */
    public LogicalSnapshot(RelOptCluster cluster, RelTraitSet traitSet,
        RelNode input, RexNode period) {
      super(cluster, traitSet, ImmutableList.of(), input, period);
    }
  
    @Override public Snapshot copy(RelTraitSet traitSet, RelNode input,
        RexNode period) {
      return new LogicalSnapshot(getCluster(), traitSet, hints, input, period);
    }
  
    /** Creates a LogicalSnapshot. */
    public static LogicalSnapshot create(RelNode input, RexNode period) {
      final RelOptCluster cluster = input.getCluster();
      final RelMetadataQuery mq = cluster.getMetadataQuery();
      final RelTraitSet traitSet = cluster.traitSet()
          .replace(Convention.NONE)
          .replaceIfs(RelCollationTraitDef.INSTANCE,
              () -> RelMdCollation.snapshot(mq, input))
          .replaceIf(RelDistributionTraitDef.INSTANCE,
              () -> RelMdDistribution.snapshot(mq, input));
      return new LogicalSnapshot(cluster, traitSet, input, period);
    }
  
    @Override public RelNode withHints(final List<RelHint> hintList) {
      return new LogicalSnapshot(getCluster(), traitSet, hintList, input, getPeriod());
    }
  }
  