content: /*
   *
   *  * Copyright 2020 Alibaba Group Holding Limited.
   *  *
   *  * Licensed 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 com.alibaba.graphscope.common.ir.rel;
  
  import com.alibaba.graphscope.common.ir.rel.graph.AbstractBindableTableScan;
  import com.alibaba.graphscope.common.ir.rel.type.TableConfig;
  import com.alibaba.graphscope.common.ir.tools.AliasInference;
  import com.alibaba.graphscope.common.ir.type.ExplicitRecordType;
  import com.google.common.collect.ImmutableList;
  
  import org.apache.calcite.plan.GraphOptCluster;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.prepare.RelOptTableImpl;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.RelShuttle;
  import org.apache.calcite.rel.hint.RelHint;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rel.type.RelDataTypeFieldImpl;
  import org.apache.calcite.rel.type.RelRecordType;
  import org.apache.calcite.schema.TranslatableTable;
  import org.apache.calcite.schema.impl.AbstractTable;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import java.util.List;
  
  public class DummyTableScan extends AbstractBindableTableScan {
      public DummyTableScan(GraphOptCluster cluster, List<RelHint> hints) {
          super(cluster, hints, createTableConfig(cluster, new Table()), AliasInference.DEFAULT_NAME);
      }
  
      private static TableConfig createTableConfig(RelOptCluster cluster, Table table) {
          RelOptTable optTable =
                  RelOptTableImpl.create(
                          null,
                          new ExplicitRecordType(
                                  cluster.getTypeFactory().createSqlType(SqlTypeName.CHAR)),
                          table,
                          ImmutableList.of("dummy"));
          return new TableConfig(ImmutableList.of(optTable));
      }
  
      @Override
      public RelDataType deriveRowType() {
          return new RelRecordType(
                  ImmutableList.of(
                          new RelDataTypeFieldImpl(
                                  getAliasName(), getAliasId(), getTable().getRowType())));
      }
  
      @Override
      public RelNode accept(RelShuttle shuttle) {
          if (shuttle instanceof GraphShuttle) {
              return ((GraphShuttle) shuttle).visit(this);
          }
          return shuttle.visit(this);
      }
  
      private static class Table extends AbstractTable implements TranslatableTable {
          @Override
          public RelNode toRel(RelOptTable.ToRelContext ctx, RelOptTable optTable) {
              return null;
          }
  
          @Override
          public RelDataType getRowType(RelDataTypeFactory typeFactory) {
              return new ExplicitRecordType(typeFactory.createSqlType(SqlTypeName.CHAR));
          }
      }
  }
  