DataAccessProvider Interface
- public interface DataAccessProvider
The DataAccessProvider interface is implemented by objects
that need to provide their children with data and wish
to make it available to them with the container
binding context. Expression evaluation will process
all container
context references against this interface;
several read-only properties are exposed:
Method | NetUI Data Binding Expression | Required |
getCurrentIndex() | container.index | Yes |
getCurrentItem() | container.item | Yes |
getCurrentMetadata() | container.metadata | No |
getDataSource() | container.dataSource | Yes |
getProviderParent() | container.container | Yes |
In cases where a DataAccessProvider contains another DataAccessProvider, the
grandparent DataAccessProvider may be referenced with the binding expression
container.container
. For example, the item, with the property firstName,
may be accessed with the expression container.container.item.firstName
.
The general use of the DataAccessProvider is as an interface that is implemented
by repeating databound tags that iterate over a data set and render each item
in that data set. The item and iteration index are exposed through this
interface and can be bound to by tags inside of the repeating tag
that implements the DataAccessProvider interface. This binding expression
should start with container
and reference one of the properties above.
-
All Known Implementing Classes
-
CellRepeater
, Grid
, Repeater
getCurrentIndex() Method
public int getCurrentIndex()
Get the current index in this iteration. This should be a
zero based integer that increments after each iteration.
Returns
- the current index of iteration or 0
getCurrentItem() Method
public Object
getCurrentItem()
Get the current data item in this DataAccessProvider.
Returns
- the current data item or
null
getCurrentMetadata() Method
public Object
getCurrentMetadata()
Get a metadata object for the current item. This interface
is optional, and implementations of this interface are
provided by the DataAccessProvider interface. See these
implementations for information about their support for
current item metadata.
Returns
- the current metadata or
null
if no metadata can be
found or metadata is not supported by a DataAccessProvider implementation
getDataSource() Method
public String
getDataSource()
Get the expression that references the data item to which the
DataAccessProvider is bound.
Returns
- the expression referencing the data source or
null
if no
dataSource is set
getProviderParent() Method
public DataAccessProvider
getProviderParent()
Get the parent DataAccessProvider of a DataAccessProvider. A DataAccessProvider
implementation may be able to nest DataAccessProviders. In this case,
it can be useful to be able to also nest access to data from parent
providers. Implementations of this interface are left with having
to discover and export parents. The return value from this call
on an implementing Object can be null
.
Returns
- the parent DataAccessProvider or
null
if this method
is not supported or the parent can not be found.
setDataSource(String) Method
public void setDataSource(String
dataSource)