Package org.apache.calcite.sql.advise

Class SqlAdvisor

  • public class SqlAdvisor
extends java.lang.Object
    An assistant which offers hints and corrections to a partially-formed SQL statement. It is used in the SQL editor user-interface.

    • Field Detail

      • LOGGER

        public static final org.slf4j.Logger LOGGER

      • UPPER_HINT_TOKEN

        private static final java.lang.String UPPER_HINT_TOKEN

      • prevWord

        private java.lang.String prevWord

      • prevPreferredCasing

        private org.apache.calcite.avatica.util.Casing prevPreferredCasing

      • reservedWordsSet

        private java.util.Set<java.lang.String> reservedWordsSet

      • reservedWordsList

        private java.util.List<java.lang.String> reservedWordsList

    • Method Detail

      • quoteStart

        private char quoteStart()

      • quoteEnd

        private char quoteEnd()

      • getCompletionHints

        public java.util.List<SqlMoniker> getCompletionHints​(java.lang.String sql,
                                                     int cursor,
                                                     java.lang.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 java.util.List<SqlMoniker> getCompletionHints0​(java.lang.String sql,
                                                      int cursor)

      • getPreferredCasing

        private org.apache.calcite.avatica.util.Casing getPreferredCasing​(java.lang.String word)
        Returns casing which is preferred for replacement. For instance, en => ename, EN => ENAME. When input has mixed case, Casing.UNCHANGED is returned.
        Parameters:
        word - input word
        Returns:
        preferred casing when replacing input word

      • getReplacement

        public java.lang.String getReplacement​(SqlMoniker hint,
                                       java.lang.String word)

      • getReplacement

        public java.lang.String getReplacement​(SqlMoniker hint,
                                       boolean quoted,
                                       org.apache.calcite.avatica.util.Casing preferredCasing)

      • matchesUnquoted

        private boolean matchesUnquoted​(java.lang.String name,
                                java.lang.String idToAppend)

      • applyCasing

        private java.lang.String applyCasing​(java.lang.String value,
                                     org.apache.calcite.avatica.util.Casing casing)

      • getCompletionHints

        public java.util.List<SqlMoniker> getCompletionHints​(java.lang.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

      • isSelectListItem

        private static boolean isSelectListItem​(SqlNode root,
                                        SqlParserPos pos,
                                        java.lang.String hintToken)

      • tryParse

        private SqlNode tryParse​(java.lang.String sql,
                         java.util.List<SqlMoniker> hintList)
        Tries to parse a SQL statement.

        If succeeds, returns the parse tree node; if fails, populates the list of hints and returns null.

        Parameters:
        sql - SQL statement
        hintList - List of hints suggesting allowable tokens at the point of failure
        Returns:
        Parse tree if succeeded, null if parse failed

      • getQualifiedName

        public SqlMoniker getQualifiedName​(java.lang.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​(java.lang.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 java.util.List<SqlAdvisor.ValidateErrorInfo> validate​(java.lang.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 java.lang.String simplifySql​(java.lang.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 java.util.List<java.lang.String> getReservedAndKeyWords()
        Return an array of SQL reserved and keywords
        Returns:
        an of SQL reserved and keywords

      • getReservedAndKeyWordsSet

        private java.util.Set<java.lang.String> getReservedAndKeyWordsSet()

      • ensureReservedAndKeyWords

        private void ensureReservedAndKeyWords()

      • 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​(java.lang.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​(java.lang.String sql,
                                     java.util.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