org.apache.calcite.sql.advise

Class SqlAdvisor

java.lang.Object

org.apache.calcite.sql.advise.SqlAdvisor

public class SqlAdvisor
extends Object

An assistant which offers hints and corrections to a partially-formed SQL statement. It is used in the SQL editor user-interface.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SqlAdvisor.ValidateErrorInfo An inner class that represents error message text and position info of a validator or parser exception

Field Summary

Fields

Modifier and Type	Field and Description
static Logger	LOGGER

Constructor Summary

Constructors

Constructor and Description
SqlAdvisor(SqlValidatorWithHints validator) Creates a SqlAdvisor with a validator instance

Method Summary

Methods

Modifier and Type	Method and Description
protected SqlNode	collectParserError(String sql, List<SqlAdvisor.ValidateErrorInfo> errorList) Attempts to parse a SQL statement and adds to the errorList if any syntax error is found.
List<SqlMoniker>	getCompletionHints(String sql, int cursor, String[] replaced) Gets completion hints for a partially completed or syntactically incorrect sql statement with cursor pointing to the position where completion hints are requested.
List<SqlMoniker>	getCompletionHints(String sql, SqlParserPos pos) Gets completion hints for a syntactically correct sql statement with dummy SqlIdentifier
List<SqlMoniker>	getCompletionHints0(String sql, int cursor)
protected SqlAbstractParserImpl.Metadata	getParserMetadata() Returns the underlying Parser metadata.
SqlMoniker	getQualifiedName(String sql, int cursor) Gets the fully qualified name for a SqlIdentifier at a given position of a sql statement.
List<String>	getReservedAndKeyWords() Return an array of SQL reserved and keywords
boolean	isValid(String sql) Attempts to complete and validate a given partially completed sql statement, and returns whether it is valid.
protected SqlNode	parseQuery(String sql) Wrapper function to parse a SQL query (SELECT or VALUES, but not INSERT, UPDATE, DELETE, CREATE, DROP etc.), throwing a SqlParseException if the statement is not syntactically valid.
String	simplifySql(String sql, int cursor) Turns a partially completed or syntactically incorrect sql statement into a simplified, valid one that can be passed into getCompletionHints()
List<SqlAdvisor.ValidateErrorInfo>	validate(String sql) Attempts to parse and validate a SQL statement.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOGGER

public static final Logger LOGGER

Constructor Detail

SqlAdvisor

public SqlAdvisor(SqlValidatorWithHints validator)

Creates a SqlAdvisor with a validator instance

Parameters:

validator - Validator

Method Detail

getCompletionHints

public List<SqlMoniker> getCompletionHints(String sql,
                                  int cursor,
                                  String[] replaced)

Gets completion hints for a partially completed or syntactically incorrect sql statement with cursor pointing to the position where completion hints are requested.

Writes into replaced[0] the string that is being replaced. Includes the cursor and the preceding identifier. For example, if sql is "select abc^de from t", sets replaced[0] to "abc". If the cursor is in the middle of whitespace, the replaced string is empty. The replaced string is never null.

Parameters:

sql - A partial or syntactically incorrect sql statement for which to retrieve completion hints

cursor - to indicate the 0-based cursor position in the query at

replaced - String which is being replaced (output)

Returns:

completion hints

getCompletionHints0

public List<SqlMoniker> getCompletionHints0(String sql,
                                   int cursor)

getCompletionHints

public List<SqlMoniker> getCompletionHints(String sql,
                                  SqlParserPos pos)

Gets completion hints for a syntactically correct sql statement with dummy SqlIdentifier

Parameters:

sql - A syntactically correct sql statement for which to retrieve completion hints

pos - to indicate the line and column position in the query at which completion hints need to be retrieved. For example, "select a.ename, b.deptno from sales.emp a join sales.dept b "on a.deptno=b.deptno where empno=1"; setting pos to 'Line 1, Column 17' returns all the possible column names that can be selected from sales.dept table setting pos to 'Line 1, Column 31' returns all the possible table names in 'sales' schema

Returns:

an array of hints (SqlMoniker) that can fill in at the indicated position

getQualifiedName

public SqlMoniker getQualifiedName(String sql,
                          int cursor)

Gets the fully qualified name for a SqlIdentifier at a given position of a sql statement.

Parameters:

sql - A syntactically correct sql statement for which to retrieve a fully qualified SQL identifier name

cursor - to indicate the 0-based cursor position in the query that represents a SQL identifier for which its fully qualified name is to be returned.

Returns:

a SqlMoniker that contains the fully qualified name of the specified SQL identifier, returns null if none is found or the SQL statement is invalid.

isValid

public boolean isValid(String sql)

Attempts to complete and validate a given partially completed sql statement, and returns whether it is valid.

Parameters:

sql - A partial or syntactically incorrect sql statement to validate

Returns:

whether SQL statement is valid

validate

public List<SqlAdvisor.ValidateErrorInfo> validate(String sql)

Attempts to parse and validate a SQL statement. Throws the first exception encountered. The error message of this exception is to be displayed on the UI

Parameters:

sql - A user-input sql statement to be validated

Returns:

a List of ValidateErrorInfo (null if sql is valid)

simplifySql

public String simplifySql(String sql,
                 int cursor)

Turns a partially completed or syntactically incorrect sql statement into a simplified, valid one that can be passed into getCompletionHints()

Parameters:

sql - A partial or syntactically incorrect sql statement

cursor - to indicate column position in the query at which completion hints need to be retrieved.

Returns:

a completed, valid (and possibly simplified SQL statement

getReservedAndKeyWords

public List<String> getReservedAndKeyWords()

Return an array of SQL reserved and keywords

Returns:

an of SQL reserved and keywords

getParserMetadata

protected SqlAbstractParserImpl.Metadata getParserMetadata()

Returns the underlying Parser metadata.

To use a different parser (recognizing a different dialect of SQL), derived class should override.

Returns:

metadata

parseQuery

protected SqlNode parseQuery(String sql)
                      throws SqlParseException

Wrapper function to parse a SQL query (SELECT or VALUES, but not INSERT, UPDATE, DELETE, CREATE, DROP etc.), throwing a SqlParseException if the statement is not syntactically valid.

Parameters:

sql - SQL statement

Returns:

parse tree

Throws:

SqlParseException - if not syntactically valid

collectParserError

protected SqlNode collectParserError(String sql,
                         List<SqlAdvisor.ValidateErrorInfo> errorList)

Attempts to parse a SQL statement and adds to the errorList if any syntax error is found. This implementation uses SqlParser. Subclass can re-implement this with a different parser implementation

Parameters:

sql - A user-input sql statement to be parsed

errorList - A List of error to be added to

Returns:

SqlNode that is root of the parse tree, null if the sql is not valid