com.vaadin.data.util.sqlcontainer.query
Interface QueryDelegate

All Superinterfaces:

Serializable

All Known Implementing Classes:

FreeformQuery, TableQuery

public interface QueryDelegate
extends Serializable

Nested Class Summary

static interface	QueryDelegate.RowIdChangeEvent An Event object specifying the old and new RowId of an added item after the addition has been successfully committed.
static interface	QueryDelegate.RowIdChangeListener RowId change listener interface.
static interface	QueryDelegate.RowIdChangeNotifier The interface for adding and removing RowIdChangeEvent listeners.

Method Summary

void	beginTransaction() Starts a new database transaction.
void	commit() Commits a transaction.
boolean	containsRowWithKey(Object... keys) Performs a query to find out whether the SQL table contains a row with the given set of primary keys.
int	getCount() Generates and executes a query to determine the current row count from the DB.
List<String>	getPrimaryKeyColumns() Returns a list of primary key column names.
ResultSet	getResults(int offset, int pagelength) Executes a paged SQL query and returns the ResultSet.
boolean	implementationRespectsPagingLimits() Allows the SQLContainer implementation to check whether the QueryDelegate implementation implements paging in the getResults method.
boolean	removeRow(RowItem row) Removes the given RowItem from the database.
void	rollback() Rolls a transaction back.
void	setFilters(List<Container.Filter> filters) Sets the filters to apply when performing the SQL query.
void	setOrderBy(List<OrderBy> orderBys) Sets the order in which to retrieve rows from the database.
int	storeRow(RowItem row) Stores a row in the database.

Method Detail

getCount

int getCount()
             throws SQLException

Generates and executes a query to determine the current row count from the DB. Row count will be fetched using filters that are currently set to the QueryDelegate.

Returns:

row count

Throws:

SQLException

getResults

ResultSet getResults(int offset,
                     int pagelength)
                     throws SQLException

Executes a paged SQL query and returns the ResultSet. The query is defined through implementations of this QueryDelegate interface.

Parameters:

offset - the first item of the page to load

pagelength - the length of the page to load

Returns:

a ResultSet containing the rows of the page

Throws:

SQLException - if the database access fails.

implementationRespectsPagingLimits

boolean implementationRespectsPagingLimits()

Allows the SQLContainer implementation to check whether the QueryDelegate implementation implements paging in the getResults method.

Returns:

true if the delegate implements paging

See Also:

getResults(int, int)

setFilters

void setFilters(List<Container.Filter> filters)
                throws UnsupportedOperationException

Sets the filters to apply when performing the SQL query. These are translated into a WHERE clause. Default filtering mode will be used.

Parameters:

filters - The filters to apply.

Throws:

UnsupportedOperationException - if the implementation doesn't support filtering.

setOrderBy

void setOrderBy(List<OrderBy> orderBys)
                throws UnsupportedOperationException

Sets the order in which to retrieve rows from the database. The result can be ordered by zero or more columns and each column can be in ascending or descending order. These are translated into an ORDER BY clause in the SQL query.

Parameters:

orderBys - A list of the OrderBy conditions.

Throws:

UnsupportedOperationException - if the implementation doesn't support ordering.

storeRow

int storeRow(RowItem row)
             throws UnsupportedOperationException,
                    SQLException

Stores a row in the database. The implementation of this interface decides how to identify whether to store a new row or update an existing one.

Parameters:

columnToValueMap - A map containing the values for all columns to be stored or updated.

Returns:

the number of affected rows in the database table

Throws:

UnsupportedOperationException - if the implementation is read only.

SQLException

removeRow

boolean removeRow(RowItem row)
                  throws UnsupportedOperationException,
                         SQLException

Removes the given RowItem from the database.

Parameters:

row - RowItem to be removed

Returns:

true on success

Throws:

UnsupportedOperationException

SQLException

beginTransaction

void beginTransaction()
                      throws SQLException

Starts a new database transaction. Used when storing multiple changes. Note that if a transaction is already open, it will be rolled back when a new transaction is started.

Throws:

SQLException - if the database access fails.

commit

void commit()
            throws SQLException

Commits a transaction. If a transaction is not open nothing should happen.

Throws:

SQLException - if the database access fails.

rollback

void rollback()
              throws SQLException

Rolls a transaction back. If a transaction is not open nothing should happen.

Throws:

SQLException - if the database access fails.

getPrimaryKeyColumns

List<String> getPrimaryKeyColumns()

Returns a list of primary key column names. The list is either fetched from the database (TableQuery) or given as an argument depending on implementation.

Returns:

containsRowWithKey

boolean containsRowWithKey(Object... keys)
                           throws SQLException

Performs a query to find out whether the SQL table contains a row with the given set of primary keys.

Parameters:

keys - the primary keys

Returns:

true if the SQL table contains a row with the provided keys

Throws:

SQLException