com.gargoylesoftware.base.resource.jdbc

Class StatementWrapper

public class StatementWrapper extends Object implements Statement

The object used for executing a static SQL statement and obtaining the results produced by it.

Only one ResultSet object per Statement object can be open at any point in time. Therefore, if the reading of one ResultSet object is interleaved with the reading of another, each must have been generated by different Statement objects. All statement execute methods implicitly close a statment's current ResultSet object if an open one exists.

Version: $Revision: 1.4 $

Author: Mike Bowler

Field Summary
Connectionconnection_
Statementdelegate_
booleanisOpen_
ListopenResultSets_
Constructor Summary
StatementWrapper(Statement statement)
Create a new wrapper
Method Summary
voidaddBatch(String sql)
Adds an SQL command to the current batch of commmands for this Statement object.
voidcancel()
Cancels this Statement object if both the DBMS and driver support aborting an SQL statement.
protected voidcheckIsOpen()
Check to see if the connection is still open
voidclearBatch()
Makes the set of commands in the current batch empty.
voidclearWarnings()
Clears all the warnings reported on this Statement object.
voidclose()
Releases this Statement object's database and JDBC resources immediately instead of waiting for this to happen when it is automatically closed.
booleanexecute(String sql)
Executes an SQL statement that may return multiple results.
booleanexecute(String sql, int autoGeneratedKeys)
Executes the given SQL statement, which may return multiple results, and signals the driver that any auto-generated keys should be made available for retrieval.
booleanexecute(String sql, int[] columnIndexes)
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
booleanexecute(String sql, String[] columnNames)
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
int[]executeBatch()
Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts.
ResultSetexecuteQuery(String sql)
Executes an SQL statement that returns a single ResultSet object.
intexecuteUpdate(String sql)
Executes an SQL INSERT, UPDATE or DELETE statement.
intexecuteUpdate(String sql, int autoGeneratedKeys)
Executes the given SQL statement and signals the driver with the given flag about whether the auto-generated keys produced by this Statement object should be made available for retrieval.
intexecuteUpdate(String sql, int[] columnIndexes)
Executes the given SQL statement and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
intexecuteUpdate(String sql, String[] columnNames)
Executes the given SQL statement and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
ConnectiongetConnection()
Returns the Connection object that produced this Statement object.
StatementgetDelegate()
Return the statement that is wrapped
intgetFetchDirection()
Retrieves the direction for fetching rows from database tables that is the default for result sets generated from this Statement object.
intgetFetchSize()
Retrieves the number of result set rows that is the default fetch size for result sets generated from this Statement object.
ResultSetgetGeneratedKeys()
Retrieves any auto-generated keys created as a result of executing this Statement object.
intgetMaxFieldSize()
Returns the maximum number of bytes allowed for any column value.
intgetMaxRows()
Retrieves the maximum number of rows that a ResultSet object can contain.
booleangetMoreResults()
Moves to a Statement object's next result.
booleangetMoreResults(int current)
Moves to this Statement object's next result, deals with any current ResultSet object(s) according to the instructions specified by the given flag, and returns true if the next result is a ResultSet object.
intgetQueryTimeout()
Retrieves the number of seconds the driver will wait for a Statement object to execute.
ResultSetgetResultSet()
Returns the current result as a ResultSet object.
intgetResultSetConcurrency()
Retrieves the result set concurrency for ResultSet objects generated by this Statement object.
intgetResultSetHoldability()
Retrieves the result set holdability for ResultSet objects generated by this Statement object.
intgetResultSetType()
Retrieves the result set type for ResultSet objects generated by this Statement object.
intgetUpdateCount()
Returns the current result as an update count; if the result is a ResultSet object or there are no more results, -1 is returned.
SQLWarninggetWarnings()
Retrieves the first warning reported by calls on this Statement object.
booleanisClosed()
Return true if this statement has been closed
voidsetConnection(Connection connection)
Set the connection that created this statement
voidsetCursorName(String name)
Defines the SQL cursor name that will be used by subsequent Statement object execute methods.
voidsetEscapeProcessing(boolean enable)
Sets escape processing on or off.
voidsetFetchDirection(int direction)
Gives the driver a hint as to the direction in which the rows in a result set will be processed.
voidsetFetchSize(int rows)
Gives the JDBC driver a hint as to the number of rows that should be fetched from the database when more rows are needed.
voidsetMaxFieldSize(int max)
Sets the limit for the maximum number of bytes in a column to the given number of bytes.
voidsetMaxRows(int max)
Sets the limit for the maximum number of rows that any ResultSet object can contain to the given number.
voidsetQueryTimeout(int seconds)
Sets the number of seconds the driver will wait for a Statement object to execute to the given number of seconds.
protected ResultSetwrapResultSet(ResultSet resultSet)
Wrap the specified result set in a ResultSetWrapper object and return the wrapper.

Field Detail

connection_

private Connection connection_

delegate_

private Statement delegate_

isOpen_

private boolean isOpen_

openResultSets_

private final List openResultSets_

Constructor Detail

StatementWrapper

public StatementWrapper(Statement statement)
Create a new wrapper

Parameters: statement The statement that we are wrapping

Method Detail

addBatch

public final void addBatch(String sql)
Adds an SQL command to the current batch of commmands for this Statement object. This method is optional.

Parameters: sql typically this is a static SQL INSERT or UPDATE statement

Throws: SQLException if a database access error occurs, or the driver does not support batch statements

Since: 1.2

cancel

public final void cancel()
Cancels this Statement object if both the DBMS and driver support aborting an SQL statement. This method can be used by one thread to cancel a statement that is being executed by another thread.

Throws: SQLException if a database access error occurs

checkIsOpen

protected final void checkIsOpen()
Check to see if the connection is still open

Throws: SQLException If an error occurs

clearBatch

public final void clearBatch()
Makes the set of commands in the current batch empty. This method is optional.

Throws: SQLException if a database access error occurs or the driver does not support batch statements

Since: 1.2

clearWarnings

public final void clearWarnings()
Clears all the warnings reported on this Statement object. After a call to this method, the method getWarnings will return null until a new warning is reported for this Statement object.

Throws: SQLException if a database access error occurs

close

public final void close()
Releases this Statement object's database and JDBC resources immediately instead of waiting for this to happen when it is automatically closed. It is generally good practice to release resources as soon as you are finished with them to avoid tying up database resources.

Note: A Statement object is automatically closed when it is garbage collected. When a Statement object is closed, its current ResultSet object, if one exists, is also closed.

Throws: SQLException if a database access error occurs

execute

public final boolean execute(String sql)
Executes an SQL statement that may return multiple results. Under some (uncommon) situations a single SQL statement may return multiple result sets and/or update counts. Normally you can ignore this unless you are (1) executing a stored procedure that you know may return multiple results or (2) you are dynamically executing an unknown SQL string. The methods execute, getMoreResults, getResultSet , and getUpdateCount let you navigate through multiple results. The execute method executes an SQL statement and indicates the form of the first result. You can then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters: sql any SQL statement

Returns: true if the next result is a ResultSet object; false if it is an update count or there are no more results

Throws: SQLException if a database access error occurs

execute

public boolean execute(String sql, int autoGeneratedKeys)
Executes the given SQL statement, which may return multiple results, and signals the driver that any auto-generated keys should be made available for retrieval. The driver will ignore this signal if the SQL statement is not an INSERT statement.

In some (uncommon) situations, a single SQL statement may return multiple result sets and/or update counts. Normally you can ignore this unless you are (1) executing a stored procedure that you know may return multiple results or (2) you are dynamically executing an unknown SQL string.

The execute method executes an SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters: sql any SQL statement autoGeneratedKeys a constant indicating whether auto-generated keys should be made available for retrieval using the method getGeneratedKeys; one of the following constants: Statement.RETURN_GENERATED_KEYS or Statement.NO_GENERATED_KEYS

Returns: true if the first result is a ResultSet object; false if it is an update count or there are no results

Throws: SQLException if a database access error occurs

Since: java 1.4

execute

public boolean execute(String sql, int[] columnIndexes)
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. This array contains the indexes of the columns in the target table that contain the auto-generated keys that should be made available. The driver will ignore the array if the given SQL statement is not an INSERT statement.

Under some (uncommon) situations, a single SQL statement may return multiple result sets and/or update counts. Normally you can ignore this unless you are (1) executing a stored procedure that you know may return multiple results or (2) you are dynamically executing an unknown SQL string.

The execute method executes an SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters: sql any SQL statement columnIndexes an array of the indexes of the columns in the inserted row that should be made available for retrieval by a call to the method getGeneratedKeys

Returns: true if the first result is a ResultSet object; false if it is an update count or there are no results

Throws: SQLException if a database access error occurs

Since: java 1.4

execute

public boolean execute(String sql, String[] columnNames)
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. This array contains the names of the columns in the target table that contain the auto-generated keys that should be made available. The driver will ignore the array if the given SQL statement is not an INSERT statement.

In some (uncommon) situations, a single SQL statement may return multiple result sets and/or update counts. Normally you can ignore this unless you are (1) executing a stored procedure that you know may return multiple results or (2) you are dynamically executing an unknown SQL string.

The execute method executes an SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters: sql any SQL statement columnNames an array of the names of the columns in the inserted row that should be made available for retrieval by a call to the method getGeneratedKeys

Returns: true if the next result is a ResultSet object; false if it is an update count or there are no more results

Throws: SQLException if a database access error occurs

Since: java 1.4

executeBatch

public final int[] executeBatch()
Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts. The int elements of the array that is returned are ordered to correspond to the commands in the batch, which are ordered according to the order in which they were added to the batch. The elements in the array returned by the method executeBatch may be one of the following:
  1. A number greater than or equal to zero -- indicates that the command was processed successfully and is an update count giving the number of rows in the database that were affected by the command's execution
  2. A value of -2 -- indicates that the command was processed successfully but that the number of rows affected is unknown

    If one of the commands in a batch update fails to execute properly, this method throws a BatchUpdateException, and a JDBC driver may or may not continue to process the remaining commands in the batch. However, the driver's behavior must be consistent with a particular DBMS, either always continuing to process commands or never continuing to process commands. If the driver continues processing after a failure, the array returned by the method BatchUpdateException.getUpdateCounts will contain as many elements as there are commands in the batch, and at least one of the elements will be the following:

  3. A value of -3 -- indicates that the command failed to execute successfully and occurs only if a driver continues to process commands after a command fails

A driver is not required to implement this method. The possible implementations and return values have been modified in the Java 2 SDK, Standard Edition, version 1.3 to accommodate the option of continuing to proccess commands in a batch update after a BatchUpdateException object has been thrown.

Returns: an array of update counts containing one element for each command in the batch. The elements of the array are ordered according to the order in which commands were added to the batch.

Throws: SQLException if a database access error occurs or the driver does not support batch statements. Throws BatchUpdateException (a subclass of SQLException) if one of the commands sent to the database fails to execute properly or attempts to return a result set.

Since: 1.3

executeQuery

public final ResultSet executeQuery(String sql)
Executes an SQL statement that returns a single ResultSet object.

Parameters: sql typically this is a static SQL SELECT statement

Returns: a ResultSet object that contains the data produced by the given query; never null

Throws: SQLException if a database access error occurs

executeUpdate

public final int executeUpdate(String sql)
Executes an SQL INSERT, UPDATE or DELETE statement. In addition, SQL statements that return nothing, such as SQL DDL statements, can be executed.

Parameters: sql an SQL INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing

Returns: either the row count for INSERT, UPDATE or DELETE statements, or 0 for SQL statements that return nothing

Throws: SQLException if a database access error occurs

executeUpdate

public int executeUpdate(String sql, int autoGeneratedKeys)
Executes the given SQL statement and signals the driver with the given flag about whether the auto-generated keys produced by this Statement object should be made available for retrieval.

Parameters: sql must be an SQL INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing autoGeneratedKeys a flag indicating whether auto-generated keys should be made available for retrieval; one of the following constants: Statement.RETURN_GENERATED_KEYS Statement.NO_GENERATED_KEYS

Returns: either the row count for INSERT, UPDATE or DELETE statements, or 0 for SQL statements that return nothing

Throws: SQLException if a database access error occurs, the given SQL statement returns a ResultSet object, or the given constant is not one of those allowed

Since: java 1.4

executeUpdate

public int executeUpdate(String sql, int[] columnIndexes)
Executes the given SQL statement and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. The driver will ignore the array if the SQL statement is not an INSERT statement.

Parameters: sql an SQL INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing, such as an SQL DDL statement columnIndexes an array of column indexes indicating the columns that should be returned from the inserted row

Returns: either the row count for INSERT, UPDATE, or DELETE statements, or 0 for SQL statements that return nothing

Throws: SQLException if a database access error occurs or the SQL statement returns a ResultSet object

Since: java 1.4

executeUpdate

public int executeUpdate(String sql, String[] columnNames)
Executes the given SQL statement and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. The driver will ignore the array if the SQL statement is not an INSERT statement.

Parameters: sql an SQL INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing columnNames an array of the names of the columns that should be returned from the inserted row

Returns: either the row count for INSERT, UPDATE, or DELETE statements, or 0 for SQL statements that return nothing

Throws: SQLException if a database access error occurs

Since: java 1.4

getConnection

public final Connection getConnection()
Returns the Connection object that produced this Statement object.

Returns: the connection that produced this statement

Throws: SQLException if a database access error occurs

Since: 1.2

getDelegate

public final Statement getDelegate()
Return the statement that is wrapped

Returns: The wrapped statement

getFetchDirection

public final int getFetchDirection()
Retrieves the direction for fetching rows from database tables that is the default for result sets generated from this Statement object. If this Statement object has not set a fetch direction by calling the method setFetchDirection, the return value is implementation-specific.

Returns: the default fetch direction for result sets generated from this Statement object

Throws: SQLException if a database access error occurs

Since: 1.2

getFetchSize

public final int getFetchSize()
Retrieves the number of result set rows that is the default fetch size for result sets generated from this Statement object. If this Statement object has not set a fetch size by calling the method setFetchSize, the return value is implementation-specific.

Returns: the default fetch size for result sets generated from this Statement object

Throws: SQLException if a database access error occurs

Since: 1.2

getGeneratedKeys

public ResultSet getGeneratedKeys()
Retrieves any auto-generated keys created as a result of executing this Statement object. If this Statement object did not generate any keys, an empty ResultSet object is returned.

Returns: a ResultSet object containing the auto-generated key(s) generated by the execution of this Statement object

Throws: SQLException if a database access error occurs

Since: java 1.4

getMaxFieldSize

public final int getMaxFieldSize()
Returns the maximum number of bytes allowed for any column value. This limit is the maximum number of bytes that can be returned for any column value. The limit applies only to BINARY, VARBINARY , LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns. If the limit is exceeded, the excess data is silently discarded.

Returns: the current max column size limit; zero means unlimited

Throws: SQLException if a database access error occurs

getMaxRows

public final int getMaxRows()
Retrieves the maximum number of rows that a ResultSet object can contain. If the limit is exceeded, the excess rows are silently dropped.

Returns: the current max row limit; zero means unlimited

Throws: SQLException if a database access error occurs

getMoreResults

public final boolean getMoreResults()
Moves to a Statement object's next result. It returns true if this result is a ResultSet object. This method also implicitly closes any current ResultSet object obtained with the method getResultSet.

There are no more results when the following is true:

      (!getMoreResults() && (getUpdateCount() == -1) 

Returns: true if the next result is a ResultSet object; false if it is an update count or there are no more results

Throws: SQLException if a database access error occurs

getMoreResults

public boolean getMoreResults(int current)
Moves to this Statement object's next result, deals with any current ResultSet object(s) according to the instructions specified by the given flag, and returns true if the next result is a ResultSet object.

There are no more results when the following is true:

      (!getMoreResults() && (getUpdateCount() == -1)
 

Parameters: current one of the following Statement constants indicating what should happen to current ResultSet objects obtained using the method getResultSetCLOSE_CURRENT_RESULT, KEEP_CURRENT_RESULT, or CLOSE_ALL_RESULTS

Returns: true if the next result is a ResultSet object; false if it is an update count or there are no more results

Throws: SQLException if a database access error occurs

Since: 1.4

getQueryTimeout

public final int getQueryTimeout()
Retrieves the number of seconds the driver will wait for a Statement object to execute. If the limit is exceeded, a SQLException is thrown.

Returns: the current query timeout limit in seconds; zero means unlimited

Throws: SQLException if a database access error occurs

getResultSet

public final ResultSet getResultSet()
Returns the current result as a ResultSet object. This method should be called only once per result.

Returns: the current result as a ResultSet object; null if the result is an update count or there are no more results

Throws: SQLException if a database access error occurs

getResultSetConcurrency

public final int getResultSetConcurrency()
Retrieves the result set concurrency for ResultSet objects generated by this Statement object.

Returns: either ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE

Throws: SQLException If an error occurs

Since: 1.2

getResultSetHoldability

public int getResultSetHoldability()
Retrieves the result set holdability for ResultSet objects generated by this Statement object.

Returns: either ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT

Throws: SQLException if a database access error occurs

Since: java 1.4

getResultSetType

public final int getResultSetType()
Retrieves the result set type for ResultSet objects generated by this Statement object.

Returns: one of ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE , or ResultSet.TYPE_SCROLL_SENSITIVE

Throws: SQLException If an error occurs

Since: 1.2

getUpdateCount

public final int getUpdateCount()
Returns the current result as an update count; if the result is a ResultSet object or there are no more results, -1 is returned. This method should be called only once per result.

Returns: the current result as an update count; -1 if the current result is a ResultSet object or there are no more results

Throws: SQLException if a database access error occurs

getWarnings

public final SQLWarning getWarnings()
Retrieves the first warning reported by calls on this Statement object. Subsequent Statement object warnings will be chained to this SQLWarning object.

The warning chain is automatically cleared each time a statement is (re)executed.

Note: If you are processing a ResultSet object, any warnings associated with reads on that ResultSet object will be chained on it.

Returns: the first SQLWarning object or null

Throws: SQLException if a database access error occurs

isClosed

public final boolean isClosed()
Return true if this statement has been closed

Returns: true if this statement has been closed

setConnection

public final void setConnection(Connection connection)
Set the connection that created this statement

Parameters: connection The connection

setCursorName

public final void setCursorName(String name)
Defines the SQL cursor name that will be used by subsequent Statement object execute methods. This name can then be used in SQL positioned update/delete statements to identify the current row in the ResultSet object generated by this statement. If the database doesn't support positioned update/delete, this method is a noop. To insure that a cursor has the proper isolation level to support updates, the cursor's SELECT statement should be of the form 'select for update ...'. If the 'for update' phrase is omitted, positioned updates may fail.

Note: By definition, positioned update/delete execution must be done by a different Statement object than the one which generated the ResultSet object being used for positioning. Also, cursor names must be unique within a connection.

Parameters: name the new cursor name, which must be unique within a connection

Throws: SQLException if a database access error occurs

setEscapeProcessing

public final void setEscapeProcessing(boolean enable)
Sets escape processing on or off. If escape scanning is on (the default), the driver will do escape substitution before sending the SQL to the database. Note: Since prepared statements have usually been parsed prior to making this call, disabling escape processing for prepared statements will have no effect.

Parameters: enable true to enable; false to disable

Throws: SQLException if a database access error occurs

setFetchDirection

public final void setFetchDirection(int direction)
Gives the driver a hint as to the direction in which the rows in a result set will be processed. The hint applies only to result sets created using this Statement object. The default value is ResultSet.FETCH_FORWARD.

Note that this method sets the default fetch direction for result sets generated by this Statement object. Each result set has its own methods for getting and setting its own fetch direction.

Parameters: direction the initial direction for processing rows

Throws: SQLException if a database access error occurs or the given direction is not one of ResultSet.FETCH_FORWARD, ResultSet.FETCH_REVERSE , or ResultSet.FETCH_UNKNOWN

Since: 1.2

setFetchSize

public final void setFetchSize(int rows)
Gives the JDBC driver a hint as to the number of rows that should be fetched from the database when more rows are needed. The number of rows specified affects only result sets created using this statement. If the value specified is zero, then the hint is ignored. The default value is zero.

Parameters: rows the number of rows to fetch

Throws: SQLException if a database access error occurs, or the condition 0 <= rows <= this.getMaxRows() is not satisfied.

Since: 1.2

setMaxFieldSize

public final void setMaxFieldSize(int max)
Sets the limit for the maximum number of bytes in a column to the given number of bytes. This is the maximum number of bytes that can be returned for any column value. This limit applies only to BINARY , VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR fields. If the limit is exceeded, the excess data is silently discarded. For maximum portability, use values greater than 256.

Parameters: max the new max column size limit; zero means unlimited

Throws: SQLException if a database access error occurs

setMaxRows

public final void setMaxRows(int max)
Sets the limit for the maximum number of rows that any ResultSet object can contain to the given number. If the limit is exceeded, the excess rows are silently dropped.

Parameters: max the new max rows limit; zero means unlimited

Throws: SQLException if a database access error occurs

setQueryTimeout

public final void setQueryTimeout(int seconds)
Sets the number of seconds the driver will wait for a Statement object to execute to the given number of seconds. If the limit is exceeded, an SQLException is thrown.

Parameters: seconds the new query timeout limit in seconds; zero means unlimited

Throws: SQLException if a database access error occurs

wrapResultSet

protected final ResultSet wrapResultSet(ResultSet resultSet)
Wrap the specified result set in a ResultSetWrapper object and return the wrapper.

Parameters: resultSet The object to be wrapped

Returns: The wrapper.