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.RelOptTable;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelCollationTraitDef;
  import org.apache.calcite.rel.RelInput;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.TableScan;
  import org.apache.calcite.rel.hint.RelHint;
  import org.apache.calcite.schema.Table;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.List;
  
  /**
   * A <code>LogicalTableScan</code> reads all the rows from a
   * {@link RelOptTable}.
   *
   * <p>If the table is a <code>net.sf.saffron.ext.JdbcTable</code>, then this is
   * literally possible. But for other kinds of tables, there may be many ways to
   * read the data from the table. For some kinds of table, it may not even be
   * possible to read all of the rows unless some narrowing constraint is applied.
   *
   * <p>In the example of the <code>net.sf.saffron.ext.ReflectSchema</code>
   * schema,
   *
   * <blockquote>
   * <pre>select from fields</pre>
   * </blockquote>
   *
   * <p>cannot be implemented, but
   *
   * <blockquote>
   * <pre>select from fields as f
   * where f.getClass().getName().equals("java.lang.String")</pre>
   * </blockquote>
   *
   * <p>can. It is the optimizer's responsibility to find these ways, by applying
   * transformation rules.
   */
  public final class LogicalTableScan extends TableScan {
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a LogicalTableScan.
     *
     * <p>Use {@link #create} unless you know what you're doing.
     */
    public LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet,
        List<RelHint> hints, RelOptTable table) {
      super(cluster, traitSet, hints, table);
    }
  
    @Deprecated // to be removed before 2.0
    public LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet,
        RelOptTable table) {
      this(cluster, traitSet, ImmutableList.of(), table);
    }
  
    @Deprecated // to be removed before 2.0
    public LogicalTableScan(RelOptCluster cluster, RelOptTable table) {
      this(cluster, cluster.traitSetOf(Convention.NONE), ImmutableList.of(), table);
    }
  
    /**
     * Creates a LogicalTableScan by parsing serialized output.
     */
    public LogicalTableScan(RelInput input) {
      super(input);
    }
  
    @Override public RelNode copy(RelTraitSet traitSet, List<RelNode> inputs) {
      assert traitSet.containsIfApplicable(Convention.NONE);
      assert inputs.isEmpty();
      return this;
    }
  
    /** Creates a LogicalTableScan.
     *
     * @param cluster     Cluster
     * @param relOptTable Table
     * @param hints       The hints
     */
    public static LogicalTableScan create(RelOptCluster cluster,
        final RelOptTable relOptTable, List<RelHint> hints) {
      final Table table = relOptTable.unwrap(Table.class);
      final RelTraitSet traitSet =
          cluster.traitSetOf(Convention.NONE)
              .replaceIfs(RelCollationTraitDef.INSTANCE, () -> {
                if (table != null) {
                  return table.getStatistic().getCollations();
                }
                return ImmutableList.of();
              });
      return new LogicalTableScan(cluster, traitSet, hints, relOptTable);
    }
  
    @Override public RelNode withHints(List<RelHint> hintList) {
      return new LogicalTableScan(getCluster(), traitSet, hintList, table);
    }
  }
  