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.jdbc;
  
  import org.apache.calcite.adapter.java.JavaTypeFactory;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.CorrelationId;
  import org.apache.calcite.rel.rel2sql.RelToSqlConverter;
  import org.apache.calcite.rel.rel2sql.SqlImplementor;
  import org.apache.calcite.rel.type.RelDataTypeField;
  import org.apache.calcite.rex.RexCorrelVariable;
  import org.apache.calcite.sql.SqlDialect;
  import org.apache.calcite.sql.SqlDynamicParam;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.parser.SqlParserPos;
  
  import java.lang.reflect.Type;
  import java.util.List;
  
  /**
   * State for generating a SQL statement.
   */
  public class JdbcImplementor extends RelToSqlConverter {
  
    private final JdbcCorrelationDataContextBuilder dataContextBuilder;
    private final JavaTypeFactory typeFactory;
  
    JdbcImplementor(SqlDialect dialect, JavaTypeFactory typeFactory,
        JdbcCorrelationDataContextBuilder dataContextBuilder) {
      super(dialect);
      this.typeFactory = typeFactory;
      this.dataContextBuilder = dataContextBuilder;
    }
  
    public JdbcImplementor(SqlDialect dialect, JavaTypeFactory typeFactory) {
      this(dialect, typeFactory, new JdbcCorrelationDataContextBuilder() {
        private int counter = 1;
        @Override public int add(CorrelationId id, int ordinal, Type type) {
          return counter++;
        }
      });
    }
  
    public Result implement(RelNode node) {
      return dispatch(node);
    }
  
    @Override protected Context getAliasContext(RexCorrelVariable variable) {
      Context context = correlTableMap.get(variable.id);
      if (context != null) {
        return context;
      }
      List<RelDataTypeField>  fieldList = variable.getType().getFieldList();
      // We need to provide a context which also includes the correlation variables
      // as dynamic parameters.
      return new Context(dialect, fieldList.size()) {
        @Override public SqlNode field(int ordinal) {
          RelDataTypeField field = fieldList.get(ordinal);
          return new SqlDynamicParam(
              dataContextBuilder.add(variable.id, ordinal,
              typeFactory.getJavaClass(field.getType())), SqlParserPos.ZERO);
        }
  
        @Override public SqlImplementor implementor() {
          return JdbcImplementor.this;
        }
      };
    }
  }
  