javax.infobus
Interface DataItemView


public abstract interface DataItemView

Producers may implement DataItemView to optimize the management of a view of the contents of a particular subset of records. The view is a two-dimensional ArrayAccess data item which represents the window of data that is currently visible to the consumer.

For example, a consumer of a ScrollableRowsetAccess object that implements DataItemView can use this interface to paint the cells in a grid view of a subset of its rows. As the view is scrolled through the rowset, the items in the view will track the values of the cells in the view.


Method Summary
 ArrayAccess getView(int viewSize)
          Returns an object that implements an two-dimensional ArrayAccess to represent a row and column view with viewSize rows.
 int getViewStart()
          Returns the current value of the ViewStart property.
 void scrollView(int relativeAmount)
          Changes ViewStart by relativeAmount relative to its current position.
 void setViewStart(int absoluteRow)
          Sets ViewStart to absoluteRow.
 

Method Detail

setViewStart

public void setViewStart(int absoluteRow)
Sets ViewStart to absoluteRow. The ViewStart property indicates the number of the row in the row set that is seen as the first row of the view. There is no relationship between the current row of the rowset and the ViewStart; it is possible to scroll the view without affecting the current row, or change the current row without scrolling the view.

getViewStart

public int getViewStart()
Returns the current value of the ViewStart property.

scrollView

public void scrollView(int relativeAmount)
Changes ViewStart by relativeAmount relative to its current position.

getView

public ArrayAccess getView(int viewSize)
Returns an object that implements an two-dimensional ArrayAccess to represent a row and column view with viewSize rows. The array must be two-dimensional and read-only (attempts to set new values must throw an exception). The two dimensions correspond to row and column numbers in the view, respectively, and are zero-relative.

Sub-items returned by this ArrayAccess should be ImmediateAccess items that correspond to the current view to provide standard access to the values in each sub-item. If the ViewStart property changes, the values returned by items in the array change so that the view maps to a different range of rows in the row set.