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## net.sourceforge.jtds.jdbc
Class JtdsStatement

    java.lang.Object
      |
      +--net.sourceforge.jtds.jdbc.JtdsStatement

All Implemented Interfaces:
  java.sql.Statement

Direct Known Subclasses:
  JtdsPreparedStatement

public class JtdsStatement
extends java.lang.Object
implements java.sql.Statement

jTDS implementation of the java.sql.Statement interface.

NB. As allowed by the JDBC standard and like most other drivers, this implementation only allows one open result set at a time.

Implementation notes:

I experimented with allowing multiple open result sets as supported by the origianal jTDS but rejected this approach for the following reasons:

1. It is more difficult to ensure that there are no memory leaks and that cursors are closed if multiple open sets are allowed.
2. The use of one result set allows cursor and non cursor result sets to be derived from exeuteQuery() or execute() and getResultSet() in the same way that other drivers do.

In the event of an IO failure the setClosed() method forces this statement and associated result set to close preventing the propogation of errors. This class includes a finalize method which increases the chances of the statement being closed tidly in a pooled environment where the user has forgotten to explicitly close the statement before it goes out of scope.

Version:
  $Id: JtdsStatement.java,v 1.54 2005/10/27 13:22:33 alin_sinpalean Exp $
Author:
  Mike Hutchinson
See Also:
  `Statement`, `Connection.createStatement()`, `ResultSet`

Field Summary
`protected java.util.ArrayList` | `batchValues` Batched SQL Statement array.
`(package private) static int` | `BOOLEAN`
`(package private) static int` | `CLOSE_ALL_RESULTS`
`(package private) static int` | `CLOSE_CURRENT_RESULT`
`protected boolean` | `closed` True if this statement is closed.
`protected ColInfo[]` | `colMetaData` The cached column meta data.
`protected ConnectionJDBC2` | `connection` The connection owning this statement object.
`protected JtdsResultSet` | `currentResult` The current `ResultSet`.
`protected java.lang.String` | `cursorName` The cursor name to be used for positioned updates.
`(package private) static int` | `DATALINK`
`(package private) static int` | `DEFAULT_FETCH_SIZE`
`protected boolean` | `escapeProcessing` True if SQL statements should be preprocessed.
`(package private) static java.lang.Integer` | `EXECUTE_FAILED`
`protected int` | `fetchDirection` The fetch direction for result sets.
`protected int` | `fetchSize` The fetch size (default 100, only used by cursor `ResultSet`s).
`protected JtdsResultSet` | `genKeyResultSet` Dummy result set for getGeneratedKeys.
`(package private) static int` | `KEEP_CURRENT_RESULT`
`protected int` | `maxFieldSize` The maximum field size (not used at present).
`protected int` | `maxRows` The maximum number of rows to return (not used at present).
`protected SQLDiagnostic` | `messages` SQL Diagnostic exceptions and warnings.
`(package private) static int` | `NO_GENERATED_KEYS`
`protected java.util.ArrayList` | `openResultSets` List of open result sets.
`protected int` | `queryTimeout` The read query timeout in seconds
`protected java.util.LinkedList` | `resultQueue` List of queued results (update counts, possibly followed by a `ResultSet`).
`protected int` | `resultSetConcurrency` The concurrency of result sets created by this statement.
`protected int` | `resultSetType` The type of result sets created by this statement.
`(package private) static int` | `RETURN_GENERATED_KEYS`
`(package private) static java.lang.Integer` | `SUCCESS_NO_INFO`
`protected TdsCore` | `tds` The TDS object used for server access.
`private int` | `updateCount` The current update count.

Constructor Summary
`(package private)` | `JtdsStatement(ConnectionJDBC2 connection, int resultSetType, int resultSetConcurrency)` Construct a new Statement object.

Method Summary
`void` | `addBatch(java.lang.String sql)`
`(package private) void` | `addWarning(java.sql.SQLWarning w)` Add an SQLWarning object to the statment warnings list.
`protected void` | `cacheResults()` Cache as many results as possible (up to the first `ResultSet`).
`void` | `cancel()`
`protected void` | `checkCursorException(java.sql.SQLException e)` Check that the exception is caused by the failure to open a cursor and not by a more serious SQL error.
`protected void` | `checkOpen()` Check that this statement is still open.
`void` | `clearBatch()`
`void` | `clearWarnings()`
`void` | `close()`
`(package private) void` | `closeAllResultSets()` Close all result sets.
`(package private) void` | `closeCurrentResultSet()` Close current result set (if any).
`boolean` | `execute(java.lang.String sql)`
`boolean` | `execute(java.lang.String sql, int autoGeneratedKeys)`
`boolean` | `execute(java.lang.String sql, int[] columnIndexes)`
`boolean` | `execute(java.lang.String sql, java.lang.String[] columnNames)`
`int[]` | `executeBatch()` Execute batch of SQL Statements.
`protected void` | `executeBatchOther(java.lang.Object value, boolean last)` This method should be over-ridden by any sub-classes that place values other than `String`s into the `batchValues` list to handle execution properly.
`private boolean` | `executeImpl(java.lang.String sql, int autoGeneratedKeys, boolean update)` Implements the common functionality for plain statement `execute(java.lang.String)` and {#link #executeUpdate}: basic checks, cleaning up of previous results, setting up and executing the query and loading the first results.
`java.sql.ResultSet` | `executeQuery(java.lang.String sql)`
`protected boolean` | `executeSQL(java.lang.String sql, java.lang.String spName, ParamInfo[] params, boolean returnKeys, boolean update, boolean useCursor)` Executes any type of SQL.
`protected java.sql.ResultSet` | `executeSQLQuery(java.lang.String sql, java.lang.String spName, ParamInfo[] params, boolean useCursor)` Executes SQL to obtain a result set.
`int` | `executeUpdate(java.lang.String sql)`
`int` | `executeUpdate(java.lang.String sql, int autoGeneratedKeys)`
`int` | `executeUpdate(java.lang.String sql, int[] columnIndexes)`
`int` | `executeUpdate(java.lang.String sql, java.lang.String[] columnNames)`
`protected void` | `finalize()` Called when this object goes out of scope to close any `ResultSet` object and this statement.
`java.sql.Connection` | `getConnection()`
`(package private) int` | `getDefaultFetchSize()` Retrieve the default fetch size for this statement.
`int` | `getFetchDirection()`
`int` | `getFetchSize()`
`java.sql.ResultSet` | `getGeneratedKeys()`
`int` | `getMaxFieldSize()`
`int` | `getMaxRows()`
`(package private) SQLDiagnostic` | `getMessages()` Get the statement's warnings list.
`boolean` | `getMoreResults()`
`boolean` | `getMoreResults(int current)`
`int` | `getQueryTimeout()`
`java.sql.ResultSet` | `getResultSet()`
`int` | `getResultSetConcurrency()`
`int` | `getResultSetHoldability()`
`int` | `getResultSetType()`
`(package private) TdsCore` | `getTds()` Get the Statement's TDS object.
`int` | `getUpdateCount()`
`java.sql.SQLWarning` | `getWarnings()`
`protected void` | `initialize()` Initialize the `Statement`, by cleaning up all queued and unprocessed results.
`(package private) static void` | `notImplemented(java.lang.String method)` Report that user tried to call a method which has not been implemented.
`private boolean` | `processResults(boolean returnKeys, boolean update)` Queue up update counts into `resultQueue` until the end of the response is reached or a `ResultSet` is encountered.
`void` | `setCursorName(java.lang.String name)`
`void` | `setEscapeProcessing(boolean enable)`
`void` | `setFetchDirection(int direction)`
`void` | `setFetchSize(int rows)`
`void` | `setMaxFieldSize(int max)`
`void` | `setMaxRows(int max)`
`void` | `setQueryTimeout(int seconds)`
`protected boolean` | `useCursor(boolean returnKeys, java.lang.String sqlWord)` Determines whether a cursor should be used based on the requested result set type and concurrency, whether a cursor name has been set, the `useCursors` connection property has been set, the first word in the SQL query is either SELECT or EXEC/EXECUTE and no generated keys are returned.

Methods inherited from class java.lang.Object
`, clone, equals, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait`

Field Detail

### RETURN_GENERATED_KEYS

    static final int RETURN_GENERATED_KEYS

### NO_GENERATED_KEYS

    static final int NO_GENERATED_KEYS

### CLOSE_CURRENT_RESULT

    static final int CLOSE_CURRENT_RESULT

### KEEP_CURRENT_RESULT

    static final int KEEP_CURRENT_RESULT

### CLOSE_ALL_RESULTS

    static final int CLOSE_ALL_RESULTS

### BOOLEAN

    static final int BOOLEAN

### DATALINK

    static final int DATALINK

### SUCCESS_NO_INFO

    static final java.lang.Integer SUCCESS_NO_INFO

### EXECUTE_FAILED

    static final java.lang.Integer EXECUTE_FAILED

### DEFAULT_FETCH_SIZE

    static final int DEFAULT_FETCH_SIZE

### connection

    protected ConnectionJDBC2 connection

  The connection owning this statement object.

### tds

    protected TdsCore tds

  The TDS object used for server access.

### queryTimeout

    protected int queryTimeout

  The read query timeout in seconds

### currentResult

    protected JtdsResultSet currentResult

  The current `ResultSet`.

### updateCount

    private int updateCount

  The current update count.

### fetchDirection

    protected int fetchDirection

  The fetch direction for result sets.

### resultSetType

    protected int resultSetType

  The type of result sets created by this statement.

### resultSetConcurrency

    protected int resultSetConcurrency

  The concurrency of result sets created by this statement.

### fetchSize

    protected int fetchSize

  The fetch size (default 100, only used by cursor `ResultSet`s).

### cursorName

    protected java.lang.String cursorName

  The cursor name to be used for positioned updates.

### closed

    protected boolean closed

  True if this statement is closed.

### maxFieldSize

    protected int maxFieldSize

  The maximum field size (not used at present).

### maxRows

    protected int maxRows

  The maximum number of rows to return (not used at present).

### escapeProcessing

    protected boolean escapeProcessing

  True if SQL statements should be preprocessed.

### messages

    protected final SQLDiagnostic messages

  SQL Diagnostic exceptions and warnings.

### batchValues

    protected java.util.ArrayList batchValues

  Batched SQL Statement array.

### genKeyResultSet

    protected JtdsResultSet genKeyResultSet

  Dummy result set for getGeneratedKeys.

### resultQueue

    protected final java.util.LinkedList resultQueue

  List of queued results (update counts, possibly followed by a `ResultSet`).

### openResultSets

    protected java.util.ArrayList openResultSets

  List of open result sets.

### colMetaData

    protected ColInfo[] colMetaData

  The cached column meta data.

Constructor Detail

### JtdsStatement

    JtdsStatement(ConnectionJDBC2 connection,
                  int resultSetType,
                  int resultSetConcurrency)
            throws java.sql.SQLException

  Construct a new Statement object.
  Parameters:
    `connection` - The parent connection.
    `resultSetType` - The result set type for example TYPE_FORWARD_ONLY.
    `resultSetConcurrency` - The concurrency for example CONCUR_READ_ONLY.

Method Detail

### finalize

    protected void finalize()

  Called when this object goes out of scope to close any `ResultSet` object and this statement.
  Overrides:
    `finalize` in class `java.lang.Object`

### getTds

    TdsCore getTds()

  Get the Statement's TDS object.
  Returns:
    The TDS support as a `TdsCore Object.`

### getMessages

    SQLDiagnostic getMessages()

  Get the statement's warnings list.
  Returns:
    The warnings list as a `SQLDiagnostic`.

### checkOpen

    protected void checkOpen()
                      throws java.sql.SQLException

  Check that this statement is still open.
  Throws:
    `java.sql.SQLException` - if statement closed.

### checkCursorException

    protected void checkCursorException(java.sql.SQLException e)
                                 throws java.sql.SQLException

  Check that the exception is caused by the failure to open a cursor and not by a more serious SQL error.
  Parameters:
    `e` - the exception returned by the cursor class
  Throws:
    `java.sql.SQLException` - if exception is not due to a cursor error

### notImplemented

    static void notImplemented(java.lang.String method)
                        throws java.sql.SQLException

  Report that user tried to call a method which has not been implemented.
  Parameters:
    `method` - The method name to report in the error message.
  Throws:
    `java.sql.SQLException` -

### closeCurrentResultSet

    void closeCurrentResultSet()
                         throws java.sql.SQLException

  Close current result set (if any).

### closeAllResultSets

    void closeAllResultSets()
                      throws java.sql.SQLException

  Close all result sets.

### addWarning

    void addWarning(java.sql.SQLWarning w)

  Add an SQLWarning object to the statment warnings list.
  Parameters:
    `w` - The SQLWarning to add.

### executeBatchOther

    protected void executeBatchOther(java.lang.Object value,
                                     boolean last)
                              throws java.sql.SQLException

  This method should be over-ridden by any sub-classes that place values other than `String`s into the `batchValues` list to handle execution properly.
  Parameters:
    `value` - SQL `String` or list of parameters to execute
    `last` - `true` if this is the last query/parameter list in the batch

### executeSQLQuery

    protected java.sql.ResultSet executeSQLQuery(java.lang.String sql,
                                                 java.lang.String spName,
                                                 ParamInfo[] params,
                                                 boolean useCursor)
                                          throws java.sql.SQLException

  Executes SQL to obtain a result set.
  Parameters:
    `sql` - the SQL statement to execute
    `spName` - optional stored procedure name
    `params` - optional parameters
    `useCursor` - whether a cursor should be created for the SQL
  Returns:
    the result set generated by the query

### executeSQL

    protected boolean executeSQL(java.lang.String sql,
                                 java.lang.String spName,
                                 ParamInfo[] params,
                                 boolean returnKeys,
                                 boolean update,
                                 boolean useCursor)
                          throws java.sql.SQLException

  Executes any type of SQL.
  Parameters:
    `sql` - the SQL statement to execute
    `spName` - optional stored procedure name
    `params` - optional parameters
    `returnKeys` - whether the statement returns generated keys
    `update` - whether the caller is `executeUpdate(java.lang.String)`
    `useCursor` - whether the requested result set type or concurrency or connection properties request usage of a cursor
  Returns:
    `true` if the first result is a result set
  Throws:
    `java.sql.SQLException` - if an error condition occurs

### processResults

    private boolean processResults(boolean returnKeys,
                                   boolean update)
                            throws java.sql.SQLException

  Queue up update counts into `resultQueue` until the end of the response is reached or a `ResultSet` is encountered. Calling `processResults` while a `ResultSet` is open will not close it, but will consume all remaining rows.
  Parameters:
    `returnKeys` - `true` if a generated keys `ResultSet` is expected
    `update` - `true` if the method is called from within `executeUpdate`
  Returns:
    `true` if there are any results, `false` otherwise
  Throws:
    `java.sql.SQLException` - if an error condition occurs

### cacheResults

    protected void cacheResults()
                         throws java.sql.SQLException

  Cache as many results as possible (up to the first `ResultSet`). Called by `ResultSet`s when the end is reached.

### initialize

    protected void initialize()
                       throws java.sql.SQLException

  Initialize the `Statement`, by cleaning up all queued and unprocessed results. Called by all execute methods.
  Throws:
    `java.sql.SQLException` - if an error occurs

### executeImpl

    private boolean executeImpl(java.lang.String sql,
                                int autoGeneratedKeys,
                                boolean update)
                         throws java.sql.SQLException

  Implements the common functionality for plain statement `execute(java.lang.String)` and {#link #executeUpdate}: basic checks, cleaning up of previous results, setting up and executing the query and loading the first results.
  Parameters:
    `sql` - an SQL `INSERT`, `UPDATE` or `DELETE` statement or an SQL statement that returns nothing, such as an SQL DDL statement
    `autoGeneratedKeys` - a flag indicating whether auto-generated keys should be made available for retrieval
    `update` - boolean flag indicating whether the caller is `executeUpdate(java.lang.String)` -- in this case an exception is thrown if the first result is not an update count and no cursor is created (direct execution)
  Returns:
    `true` if the first result is a `ResultSet`, `false` if it's an update count
  See Also:
    `execute(java.lang.String)`, `executeUpdate(java.lang.String)`

### useCursor

    protected boolean useCursor(boolean returnKeys,
                                java.lang.String sqlWord)

  Determines whether a cursor should be used based on the requested result set type and concurrency, whether a cursor name has been set, the `useCursors` connection property has been set, the first word in the SQL query is either SELECT or EXEC/EXECUTE and no generated keys are returned.
  Parameters:
    `returnKeys` - indicates whether keys will be returned by the query
    `sqlWord` - the first word in the SQL query; can be `null` if the caller is `executeQuery(java.lang.String)`
  Returns:
    `true` if a cursor should be used, `false` if not

### getDefaultFetchSize

    int getDefaultFetchSize()

  Retrieve the default fetch size for this statement.
  Returns:
    the default fetch size for a new `ResultSet`

### getFetchDirection

    public int getFetchDirection()
                          throws java.sql.SQLException

  Specified by:
    `getFetchDirection` in interface `java.sql.Statement`

### getFetchSize

    public int getFetchSize()
                     throws java.sql.SQLException

  Specified by:
    `getFetchSize` in interface `java.sql.Statement`

### getMaxFieldSize

    public int getMaxFieldSize()
                        throws java.sql.SQLException

  Specified by:
    `getMaxFieldSize` in interface `java.sql.Statement`

### getMaxRows

    public int getMaxRows()
                   throws java.sql.SQLException

  Specified by:
    `getMaxRows` in interface `java.sql.Statement`

### getQueryTimeout

    public int getQueryTimeout()
                        throws java.sql.SQLException

  Specified by:
    `getQueryTimeout` in interface `java.sql.Statement`

### getResultSetConcurrency

    public int getResultSetConcurrency()
                                throws java.sql.SQLException

  Specified by:
    `getResultSetConcurrency` in interface `java.sql.Statement`

### getResultSetHoldability

    public int getResultSetHoldability()
                                throws java.sql.SQLException

### getResultSetType

    public int getResultSetType()
                         throws java.sql.SQLException

  Specified by:
    `getResultSetType` in interface `java.sql.Statement`

### getUpdateCount

    public int getUpdateCount()
                       throws java.sql.SQLException

  Specified by:
    `getUpdateCount` in interface `java.sql.Statement`

### cancel

    public void cancel()
                throws java.sql.SQLException

  Specified by:
    `cancel` in interface `java.sql.Statement`

### clearBatch

    public void clearBatch()
                    throws java.sql.SQLException

  Specified by:
    `clearBatch` in interface `java.sql.Statement`

### clearWarnings

    public void clearWarnings()
                       throws java.sql.SQLException

  Specified by:
    `clearWarnings` in interface `java.sql.Statement`

### close

    public void close()
               throws java.sql.SQLException

  Specified by:
    `close` in interface `java.sql.Statement`

### getMoreResults

    public boolean getMoreResults()
                           throws java.sql.SQLException

  Specified by:
    `getMoreResults` in interface `java.sql.Statement`

### executeBatch

    public int[] executeBatch()
                       throws java.sql.SQLException,
                              java.sql.BatchUpdateException

  Execute batch of SQL Statements.

  The JDBC3 standard says that for a server which does not continue processing a batch once the first error has occurred (e.g. SQL Server), the returned array will never contain `EXECUTE_FAILED` in any of the elements. If a failure has occurred the array length will be less than the count of statements in the batch. For those servers that do continue to execute a batch containing an error (e.g. Sybase), elements may contain `EXECUTE_FAILED`. Note: even here the array length may also be shorter than the statement count if a serious error has prevented the rest of the batch from being executed. In addition, when executing batched stored procedures, Sybase will also stop after the first error.
  Specified by:
    `executeBatch` in interface `java.sql.Statement`
  Returns:
    update counts as an `int[]`

### setFetchDirection

    public void setFetchDirection(int direction)
                           throws java.sql.SQLException

  Specified by:
    `setFetchDirection` in interface `java.sql.Statement`

### setFetchSize

    public void setFetchSize(int rows)
                      throws java.sql.SQLException

  Specified by:
    `setFetchSize` in interface `java.sql.Statement`

### setMaxFieldSize

    public void setMaxFieldSize(int max)
                         throws java.sql.SQLException

  Specified by:
    `setMaxFieldSize` in interface `java.sql.Statement`

### setMaxRows

    public void setMaxRows(int max)
                    throws java.sql.SQLException

  Specified by:
    `setMaxRows` in interface `java.sql.Statement`

### setQueryTimeout

    public void setQueryTimeout(int seconds)
                         throws java.sql.SQLException

  Specified by:
    `setQueryTimeout` in interface `java.sql.Statement`

### getMoreResults

    public boolean getMoreResults(int current)
                           throws java.sql.SQLException

### setEscapeProcessing

    public void setEscapeProcessing(boolean enable)
                             throws java.sql.SQLException

  Specified by:
    `setEscapeProcessing` in interface `java.sql.Statement`

### executeUpdate

    public int executeUpdate(java.lang.String sql)
                      throws java.sql.SQLException

  Specified by:
    `executeUpdate` in interface `java.sql.Statement`

### addBatch

    public void addBatch(java.lang.String sql)
                  throws java.sql.SQLException

  Specified by:
    `addBatch` in interface `java.sql.Statement`

### setCursorName

    public void setCursorName(java.lang.String name)
                       throws java.sql.SQLException

  Specified by:
    `setCursorName` in interface `java.sql.Statement`

### execute

    public boolean execute(java.lang.String sql)
                    throws java.sql.SQLException

  Specified by:
    `execute` in interface `java.sql.Statement`

### executeUpdate

    public int executeUpdate(java.lang.String sql,
                             int autoGeneratedKeys)
                      throws java.sql.SQLException

### execute

    public boolean execute(java.lang.String sql,
                           int autoGeneratedKeys)
                    throws java.sql.SQLException

### executeUpdate

    public int executeUpdate(java.lang.String sql,
                             int[] columnIndexes)
                      throws java.sql.SQLException

### execute

    public boolean execute(java.lang.String sql,
                           int[] columnIndexes)
                    throws java.sql.SQLException

### getConnection

    public java.sql.Connection getConnection()
                                      throws java.sql.SQLException

  Specified by:
    `getConnection` in interface `java.sql.Statement`

### getGeneratedKeys

    public java.sql.ResultSet getGeneratedKeys()
                                        throws java.sql.SQLException

### getResultSet

    public java.sql.ResultSet getResultSet()
                                    throws java.sql.SQLException

  Specified by:
    `getResultSet` in interface `java.sql.Statement`

### getWarnings

    public java.sql.SQLWarning getWarnings()
                                    throws java.sql.SQLException

  Specified by:
    `getWarnings` in interface `java.sql.Statement`

### executeUpdate

    public int executeUpdate(java.lang.String sql,
                             java.lang.String[] columnNames)
                      throws java.sql.SQLException

### execute

    public boolean execute(java.lang.String sql,
                           java.lang.String[] columnNames)
                    throws java.sql.SQLException

### executeQuery

    public java.sql.ResultSet executeQuery(java.lang.String sql)
                                    throws java.sql.SQLException

  Specified by:
    `executeQuery` in interface `java.sql.Statement`

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Generated on November 8 2005