/*
 * 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.phoenix.compile;

import java.sql.SQLException;
import java.util.List;
import org.apache.phoenix.parse.PFunction;
import org.apache.phoenix.parse.PSchema;
import org.apache.phoenix.schema.AmbiguousColumnException;
import org.apache.phoenix.schema.ColumnNotFoundException;
import org.apache.phoenix.schema.ColumnRef;
import org.apache.phoenix.schema.TableRef;

/**
 * Interface used to resolve column references occurring in the select statement.
 * @since 0.1
 */
public interface ColumnResolver {

  /**
   * Returns the collection of resolved tables in the FROM clause.
   */
  public List<TableRef> getTables();

  /**
   * Returns the collection of resolved functions.
   */
  public List<PFunction> getFunctions();

  /**
   * Resolves table using name or alias.
   * @param schemaName the schema name
   * @param tableName  the table name or table alias
   * @return the resolved TableRef
   */
  public TableRef resolveTable(String schemaName, String tableName) throws SQLException;

  /**
   * Resolves column using name and alias.
   * @param schemaName TODO
   * @param tableName  TODO
   * @param colName    TODO
   * @return the resolved ColumnRef
   * @throws ColumnNotFoundException  if the column could not be resolved
   * @throws AmbiguousColumnException if the column name is ambiguous
   */
  public ColumnRef resolveColumn(String schemaName, String tableName, String colName)
    throws SQLException;

  /**
   * Resolves function using functionName.
   * @return the resolved PFunction
   * @throws ColumnNotFoundException  if the column could not be resolved
   * @throws AmbiguousColumnException if the column name is ambiguous
   */
  public PFunction resolveFunction(String functionName) throws SQLException;

  public boolean hasUDFs();

  public PSchema resolveSchema(String schemaName) throws SQLException;

  public List<PSchema> getSchemas();

}
