net.sourceforge.jtds.jdbc
Class SQLParser

java.lang.Object
  net.sourceforge.jtds.jdbc.SQLParser

class SQLParser

extends java.lang.Object

Process JDBC escape strings and parameter markers in the SQL string.

This code recognizes the following escapes:

1. Date {d 'yyyy-mm-dd'}
2. Time {t 'hh:mm:ss'}
3. Timestamp {ts 'yyyy-mm-dd hh:mm:ss.nnn'}
4. ESCAPE {escape 'x'}
5. Function {fn xxxx([arg,arg...])} NB The concat(arg, arg) operator is converted to (arg + arg)
6. OuterJoin {oj .....}
7. Call {?=call proc [arg, arg...]} or {call proc [arg, arg...]}

Notes:

1. This code is designed to be as efficient as possible and as result the validation done here is limited.

   Author:

   Mike Hutchinson, Holger Rehn

   Nested Class Summary

   private static class

   SQLParser.CachedSQLQuery Serialized version of a parsed SQL query (the value stored in the cache for a parsed SQL).

   Field Summary

   private static SimpleLRUCache	_Cache a LRU cache for the last 500 parsed SQL statements
   private ConnectionJDBC2	connection Connection object for server specific parsing.
   private static java.util.HashMap	cvMap Map of jdbc to server data types for convert
   private int	d Current position in output buffer.
   private static byte[]	dateMask Syntax mask for date escape.
   private static java.util.HashMap	fnMap Map of jdbc to sybase function names.
   private static boolean[]	identifierChar Lookup table to test if character is part of an identifier.
   private char[]	in Input buffer with SQL statement.
   private java.lang.String	keyWord First SQL keyword or identifier in statement.
   private int	len Length of input buffer.
   private static java.util.HashMap	msFnMap Map of jdbc to sql server function names.
   private char[]	out Output buffer to contain parsed SQL.
   private java.util.ArrayList	params Parameter list to be populated or null if no parameters are expected.
   private java.lang.String	procName Procedure name in call escape.
   private int	s Current position in input buffer.
   private java.lang.String	sql Original SQL string
   private java.lang.String	tableName First table name in from clause
   private char	terminator Current expected terminator character.
   private static byte[]	timeMask Syntax mask for time escape.
   (package private) static byte[]	timestampMask Syntax mask for timestamp escape.

   Constructor Summary

   private

   SQLParser(java.lang.String sqlIn, java.util.ArrayList paramList, ConnectionJDBC2 connection) Constructs a new parser object to process the supplied SQL.

   Method Summary

   private void	append(char character) Adds the given character to out, incrementing d by and expanding out by a fixed number of characters if necessary.
   private void	append(char[] chars)
   private void	callEscape() Processes the JDBC {call procedure [(?
   private java.lang.String	copyKeyWord() Copies over possible SQL keyword eg 'SELECT'
   private void	copyLiteral(java.lang.String txt) Inserts a String literal in the output buffer.
   private void	copyParam(java.lang.String name, int pos) Builds a new parameter item.
   private java.lang.String	copyParamName() Copies an embedded parameter name to the output buffer.
   private java.lang.String	copyProcName() Copies an embedded stored procedure identifier over to the output buffer.
   private void	copyString() Copies over an embedded string literal unchanged.
   private void	copyWhiteSpace() Copies over white space.
   private void	escape() Processes the JDBC escape sequences.
   private void	functionEscape() Processes the JDBC escape {fn function()}.
   private boolean	getDateTimeField(byte[] mask) Utility routine to validate date and time escapes.
   private java.lang.String	getTableName() Extracts the first table name following the keyword FROM.
   private static boolean	isIdentifier(int ch) Determines if character could be part of an SQL identifier.
   private void	likeEscape() Processes the JDBC escape {escape 'X'}.
   private void	mustbe(char c, boolean copy) Checks that the next character is as expected.
   private void	outerJoinEscape() Processes the JDBC escape {oj left outer join etc}.
   (package private) java.lang.String[]	parse(boolean extractTable) Parses the SQL statement processing JDBC escapes and parameter markers.
   (package private) static java.lang.String[]	parse(java.lang.String sql, java.util.ArrayList paramList, ConnectionJDBC2 connection, boolean extractTable) Parse the SQL statement processing JDBC escapes and parameter markers.
   private void	skipMultiComments() Skips multi-line comments
   private void	skipSingleComments() Skips single-line comments.
   private void	skipWhiteSpace()

   Methods inherited from class java.lang.Object

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

   Field Detail

   _Cache

   private static final SimpleLRUCache _Cache

   a LRU cache for the last 500 parsed SQL statements

   sql

   private final java.lang.String sql

   Original SQL string

   in

   private final char[] in

   Input buffer with SQL statement.

   s

   private int s

   Current position in input buffer.

   len

   private final int len

   Length of input buffer.

   out

   private char[] out

   Output buffer to contain parsed SQL.

   d

   private int d

   Current position in output buffer.

   params

   private final java.util.ArrayList params

   Parameter list to be populated or null if no parameters are expected.

   terminator

   private char terminator

   Current expected terminator character.

   procName

   private java.lang.String procName

   Procedure name in call escape.

   keyWord

   private java.lang.String keyWord

   First SQL keyword or identifier in statement.

   tableName

   private java.lang.String tableName

   First table name in from clause

   connection

   private final ConnectionJDBC2 connection

   Connection object for server specific parsing.

   identifierChar

   private static boolean[] identifierChar

   Lookup table to test if character is part of an identifier.

   timeMask

   private static final byte[] timeMask

   Syntax mask for time escape.

   dateMask

   private static final byte[] dateMask

   Syntax mask for date escape.

   timestampMask

   static final byte[] timestampMask

   Syntax mask for timestamp escape.

   fnMap

   private static java.util.HashMap fnMap

   Map of jdbc to sybase function names.

   msFnMap

   private static java.util.HashMap msFnMap

   Map of jdbc to sql server function names.

   cvMap

   private static java.util.HashMap cvMap

   Map of jdbc to server data types for convert

   Constructor Detail

   SQLParser

   private SQLParser(java.lang.String sqlIn,
                     java.util.ArrayList paramList,
                     ConnectionJDBC2 connection)

   Constructs a new parser object to process the supplied SQL.

   Parameters:

   sqlIn - the SQL statement to parse

   paramList - the parameter list array to populate or null if no parameters are expected

   connection - the parent Connection object

   Method Detail

   parse

   static java.lang.String[] parse(java.lang.String sql,
                                   java.util.ArrayList paramList,
                                   ConnectionJDBC2 connection,
                                   boolean extractTable)
                            throws java.sql.SQLException

   Parse the SQL statement processing JDBC escapes and parameter markers.

   Parameters:

   extractTable - to return the first table name in the FROM clause of a SELECT

   Returns:

   the processed SQL statement, any procedure name, the first SQL keyword and (optionally) the first table name as elements 0, 1, 2 and 3 of the returned .

   Throws:

   java.sql.SQLException - if a parse error occurs

   isIdentifier

   private static boolean isIdentifier(int ch)

   Determines if character could be part of an SQL identifier.

   Characters > 127 are assumed to be unicode letters in other languages than english which is reasonable in this application.

   Parameters:

   ch - the character to test.

   Returns:

   boolean true if ch in A-Z a-z 0-9 @ $ # _.

   copyLiteral

   private void copyLiteral(java.lang.String txt)
                     throws java.sql.SQLException

   Inserts a String literal in the output buffer.

   Parameters:

   txt - The text to insert.

   Throws:

   java.sql.SQLException

   copyString

   private void copyString()

   Copies over an embedded string literal unchanged.

   copyKeyWord

   private java.lang.String copyKeyWord()

   Copies over possible SQL keyword eg 'SELECT'

   copyParam

   private void copyParam(java.lang.String name,
                          int pos)
                   throws java.sql.SQLException

   Builds a new parameter item.

   Parameters:

   name - Optional parameter name or null.

   pos - The parameter marker position in the output buffer.

   Throws:

   java.sql.SQLException

   copyProcName

   private java.lang.String copyProcName()
                                  throws java.sql.SQLException

   Copies an embedded stored procedure identifier over to the output buffer.

   Returns:

   The identifier as a String.

   Throws:

   java.sql.SQLException

   copyParamName

   private java.lang.String copyParamName()

   Copies an embedded parameter name to the output buffer.

   Returns:

   The identifier as a String.

   copyWhiteSpace

   private void copyWhiteSpace()

   Copies over white space.

   mustbe

   private void mustbe(char c,
                       boolean copy)
                throws java.sql.SQLException

   Checks that the next character is as expected.

   Parameters:

   c - The expected character.

   copy - True if found character should be copied.

   Throws:

   java.sql.SQLException - if expected characeter not found.

   skipWhiteSpace

   private void skipWhiteSpace()
                        throws java.sql.SQLException

   Throws:

   java.sql.SQLException

   skipSingleComments

   private void skipSingleComments()

   Skips single-line comments.

   skipMultiComments

   private void skipMultiComments()
                           throws java.sql.SQLException

   Skips multi-line comments

   Throws:

   java.sql.SQLException

   callEscape

   private void callEscape()
                    throws java.sql.SQLException

   Processes the JDBC {call procedure [(?,?,?)]} type escape.

   Throws:

   java.sql.SQLException - if an error occurs

   getDateTimeField

   private boolean getDateTimeField(byte[] mask)
                             throws java.sql.SQLException

   Utility routine to validate date and time escapes.

   Parameters:

   mask - The validation mask

   Returns:

   True if the escape was valid and processed OK.

   Throws:

   java.sql.SQLException

   outerJoinEscape

   private void outerJoinEscape()
                         throws java.sql.SQLException

   Processes the JDBC escape {oj left outer join etc}.

   Throws:

   java.sql.SQLException

   functionEscape

   private void functionEscape()
                        throws java.sql.SQLException

   Processes the JDBC escape {fn function()}.

   Throws:

   java.sql.SQLException

   likeEscape

   private void likeEscape()
                    throws java.sql.SQLException

   Processes the JDBC escape {escape 'X'}.

   Throws:

   java.sql.SQLException

   escape

   private void escape()
                throws java.sql.SQLException

   Processes the JDBC escape sequences.

   Throws:

   java.sql.SQLException

   getTableName

   private java.lang.String getTableName()
                                  throws java.sql.SQLException

   Extracts the first table name following the keyword FROM.

   Returns:

   the table name as a String

   Throws:

   java.sql.SQLException

   append

   private final void append(char[] chars)

   append

   private final void append(char character)

   Adds the given character to out, incrementing d by and expanding out by a fixed number of characters if necessary.

   parse

   java.lang.String[] parse(boolean extractTable)
                      throws java.sql.SQLException

   Parses the SQL statement processing JDBC escapes and parameter markers.

   Parameters:

   extractTable - true to return the first table name in the FROM clause of a select

   Returns:

   The processed SQL statement, any procedure name, the first SQL keyword and (optionally) the first table name as elements 0 1, 2 and 3 of the returned String[].

   Throws:

   java.sql.SQLException