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.server;
  
  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.Schemas;
  import org.apache.calcite.schema.Wrapper;
  import org.apache.calcite.schema.impl.AbstractTableQueryable;
  import org.apache.calcite.sql2rel.InitializerExpressionFactory;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.Type;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /** Table backed by a Java list. */
  class MutableArrayTable extends AbstractModifiableTable
      implements Wrapper {
    final List rows = new ArrayList();
    private final RelProtoDataType protoRowType;
    private final InitializerExpressionFactory initializerExpressionFactory;
  
    /** Creates a MutableArrayTable.
     *
     * @param name Name of table within its schema
     * @param protoStoredRowType Prototype of row type of stored columns (all
     *     columns except virtual columns)
     * @param protoRowType Prototype of row type (all columns)
     * @param initializerExpressionFactory How columns are populated
     */
    MutableArrayTable(String name, RelProtoDataType protoStoredRowType,
        RelProtoDataType protoRowType,
        InitializerExpressionFactory initializerExpressionFactory) {
      super(name);
      requireNonNull(protoStoredRowType, "protoStoredRowType");
      this.protoRowType = requireNonNull(protoRowType, "protoRowType");
      this.initializerExpressionFactory =
          requireNonNull(initializerExpressionFactory,
              "initializerExpressionFactory");
    }
  
    @Override public Collection getModifiableCollection() {
      return rows;
    }
  
    @Override public <T> Queryable<T> asQueryable(QueryProvider queryProvider,
        SchemaPlus schema, String tableName) {
      return new AbstractTableQueryable<T>(queryProvider, schema, this,
          tableName) {
        @Override public Enumerator<T> enumerator() {
          //noinspection unchecked
          return (Enumerator<T>) Linq4j.enumerator(rows);
        }
      };
    }
  
    @Override public Type getElementType() {
      return Object[].class;
    }
  
    @Override public Expression getExpression(SchemaPlus schema, String tableName,
        Class clazz) {
      return Schemas.tableExpression(schema, getElementType(),
          tableName, clazz);
    }
  
    @Override public RelDataType getRowType(RelDataTypeFactory typeFactory) {
      return protoRowType.apply(typeFactory);
    }
  
    @Override public <C extends Object> @Nullable C unwrap(Class<C> aClass) {
      if (aClass.isInstance(initializerExpressionFactory)) {
        return aClass.cast(initializerExpressionFactory);
      }
      return super.unwrap(aClass);
    }
  }
  