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.chinook;
  
  import org.apache.calcite.adapter.java.AbstractQueryableTable;
  import org.apache.calcite.linq4j.Linq4j;
  import org.apache.calcite.linq4j.QueryProvider;
  import org.apache.calcite.linq4j.Queryable;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.schema.SchemaPlus;
  import org.apache.calcite.schema.TableFactory;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import com.google.common.collect.ContiguousSet;
  import com.google.common.collect.DiscreteDomain;
  import com.google.common.collect.Range;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Map;
  
  /**
   * Factory for the table of genres preferred by the current user.
   */
  public class PreferredGenresTableFactory implements TableFactory<AbstractQueryableTable> {
    private static final Integer[] SPECIFIC_USER_PREFERRED_GENRES =
        {1, 2, 7, 9, 15};
    private static final int FIRST_ID = 1;
    private static final int LAST_ID = 25;
  
    @Override public AbstractQueryableTable create(
        SchemaPlus schema,
        String name,
        Map<String, Object> operand,
        @Nullable RelDataType rowType) {
      return new AbstractQueryableTable(Integer.class) {
        @Override public RelDataType getRowType(RelDataTypeFactory typeFactory) {
          return typeFactory.builder().add("ID", SqlTypeName.INTEGER).build();
        }
  
        @Override public Queryable<Integer> asQueryable(
            QueryProvider qp,
            SchemaPlus sp,
            String string) {
          return fetchPreferredGenres();
        }
      };
    }
  
    private static Queryable<Integer> fetchPreferredGenres() {
      if (EnvironmentFairy.getUser() == EnvironmentFairy.User.SPECIFIC_USER) {
        return Linq4j.asEnumerable(SPECIFIC_USER_PREFERRED_GENRES).asQueryable();
      } else {
        final ContiguousSet<Integer> set =
            ContiguousSet.create(Range.closed(FIRST_ID, LAST_ID),
                DiscreteDomain.integers());
        return Linq4j.asEnumerable(set).asQueryable();
      }
    }
  }
  