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.adapter.clone;
  
  import org.apache.calcite.adapter.java.AbstractQueryableTable;
  import org.apache.calcite.linq4j.AbstractQueryable;
  import org.apache.calcite.linq4j.Enumerator;
  import org.apache.calcite.linq4j.Linq4j;
  import org.apache.calcite.linq4j.QueryProvider;
  import org.apache.calcite.linq4j.Queryable;
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rel.type.RelProtoDataType;
  import org.apache.calcite.schema.SchemaPlus;
  import org.apache.calcite.schema.Statistic;
  import org.apache.calcite.schema.Statistics;
  
  import com.google.common.collect.ImmutableList;
  
  import java.lang.reflect.Type;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Implementation of table that reads rows from a read-only list and returns
   * an enumerator of rows. Each row is object (if there is just one column) or
   * an object array (if there are multiple columns).
   */
  class ListTable extends AbstractQueryableTable {
    private final RelProtoDataType protoRowType;
    private final Expression expression;
    private final List list;
  
    /** Creates a ListTable. */
    ListTable(
        Type elementType,
        RelProtoDataType protoRowType,
        Expression expression,
        List list) {
      super(elementType);
      this.protoRowType = protoRowType;
      this.expression = expression;
      this.list = list;
    }
  
    @Override public RelDataType getRowType(RelDataTypeFactory typeFactory) {
      return protoRowType.apply(typeFactory);
    }
  
    @Override public Statistic getStatistic() {
      return Statistics.of(list.size(), ImmutableList.of());
    }
  
    @Override public <T> Queryable<T> asQueryable(final QueryProvider queryProvider,
        SchemaPlus schema, String tableName) {
      return new AbstractQueryable<T>() {
        @Override public Type getElementType() {
          return elementType;
        }
  
        @Override public Expression getExpression() {
          return expression;
        }
  
        @Override public QueryProvider getProvider() {
          return queryProvider;
        }
  
        @Override public Iterator<T> iterator() {
          //noinspection unchecked
          return list.iterator();
        }
  
        @Override public Enumerator<T> enumerator() {
          //noinspection unchecked
          return Linq4j.enumerator(list);
        }
      };
    }
  }
  