Package com.vaadin.data.util.sqlcontainer.query

Class AbstractTransactionalQuery

java.lang.Object

com.vaadin.data.util.sqlcontainer.query.AbstractTransactionalQuery

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

FreeformQuery, TableQuery

public abstract class AbstractTransactionalQuery
extends Object
implements Serializable

Common base class for database query classes that handle connections and transactions.

Since:

6.8.9

Author:

Vaadin Ltd

See Also:

Serialized Form

Method Summary

Modifier and Type	Method	Description
void	beginTransaction()	Reserves a connection with auto-commit off if no transaction is in progress.
void	commit()	Commits (if not in auto-commit mode) and releases the active connection.
protected void	ensureTransaction()	Check that a transaction is active.
protected Connection	getConnection()	Returns the currently active connection, reserves and returns a new connection if no active connection.
protected boolean	isInTransaction()
protected void	releaseConnection(Connection conn, Statement statement, ResultSet rs)	Closes a statement and a resultset, then releases the connection if it is not part of an active transaction.
void	rollback()	Rolls back and releases the active connection.

Methods inherited from class java.lang.Object

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

Method Detail

beginTransaction

public void beginTransaction()
                      throws UnsupportedOperationException,
                             SQLException

Reserves a connection with auto-commit off if no transaction is in progress.

Throws:

IllegalStateException - if a transaction is already open

SQLException - if a connection could not be obtained or configured

UnsupportedOperationException

commit

public void commit()
            throws UnsupportedOperationException,
                   SQLException

Commits (if not in auto-commit mode) and releases the active connection.

Throws:

SQLException - if not in a transaction managed by this query

UnsupportedOperationException

rollback

public void rollback()
              throws UnsupportedOperationException,
                     SQLException

Rolls back and releases the active connection.

Throws:

SQLException - if not in a transaction managed by this query

UnsupportedOperationException

ensureTransaction

protected void ensureTransaction()
                          throws SQLException

Check that a transaction is active.

Throws:

SQLException - if no active transaction

releaseConnection

protected void releaseConnection(Connection conn,
                                 Statement statement,
                                 ResultSet rs)
                          throws SQLException

Closes a statement and a resultset, then releases the connection if it is not part of an active transaction. A failure in closing one of the parameters does not prevent closing the rest. If the statement is a PreparedStatement, its parameters are cleared prior to closing the statement. Although JDBC specification does state that closing a statement closes its result set and closing a connection closes statements and result sets, this method does try to close the result set and statement explicitly whenever not null. This can guard against bugs in certain JDBC drivers and reduce leaks in case e.g. closing the result set succeeds but closing the statement or connection fails.

Parameters:

conn - the connection to release

statement - the statement to close, may be null to skip closing

rs - the result set to close, may be null to skip closing

Throws:

SQLException - if closing the result set or the statement fails

getConnection

protected Connection getConnection()
                            throws SQLException

Returns the currently active connection, reserves and returns a new connection if no active connection.

Returns:

previously active or newly reserved connection

Throws:

SQLException

isInTransaction

protected boolean isInTransaction()