ilog.views.tiling

Class IlvTileLockFilter

java.lang.Object

ilog.views.tiling.IlvTileLockFilter

All Implemented Interfaces:

IlvPersistentObject, Serializable

public abstract class IlvTileLockFilter
extends Object
implements IlvPersistentObject, Serializable

This class is used to dynamically filter the loading of tiles. If a lock filter is attached to a tile controller, the controller will call the isLockAllowed function of the the filter that will potentially veto the lock of a tile that was triggered by an event in a view (unzooming, scrolling, resizing ...). This class can be used to prevent the loading of too many tiles at the same time.

The following example prevents a view which is extremely zoomed out to load more than 10 tiles at once.

  class MyLockFilter
    extends IlvTileLockFilter {

    public boolean isLockAllowed(IlvTileController tileController, 
                          IlvManagerView view)
    {
      // get the size of the view
      Dimension size = view.getSize();

      // compute the corners of the view in the manager coordinate system
      IlvTransformer t = view.getTransformer();
      if (t == null)
        return true;
      IlvRect rect = new IlvRect(0, 0, size.width, size.height);
      t.inverse(rect);

      // compute the number of visible tiles
      int indexes[] = tileController.getTileIndexes(rect);
      int horizontalTiles = 
        indexes[IlvTileController.RIGHT_COLUMN_INDEX] -
        indexes[IlvTileController.LEFT_COLUMN_INDEX] + 1;
      int verticalTiles = 
        indexes[IlvTileController.LOWER_ROW_INDEX] -
        indexes[IlvTileController.UPPER_ROW_INDEX] + 1;
      if ((horizontalTiles * verticalTiles) > 10)
        return false;
      else 
        return true;
    }

    public boolean isPersistent() 
    {
      return false;
    }
  }
 

To implement persistence, see the documentation of the IlvPersistentObject interface.

Since:

Rogue Wave JViews 3.0

See Also:

IlvTileController.setLockFilter(ilog.views.tiling.IlvTileLockFilter), Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IlvTileLockFilter() Initializes an instance of IlvTileLockFilter

Method Summary

Modifier and Type	Method and Description
abstract boolean	isLockAllowed(IlvTileController tileController, IlvManagerView view) Returns true if an event in view can lock a tile in the specified tile controller (If the tile controller is attached to a layer, this function is called only if the layer is visible in the view).
abstract boolean	isPersistent() Tells if the filter must be saved to an IVL file.
void	write(IlvOutputStream stream) Writes the filter to an IlvOutputStream.

Methods inherited from class java.lang.Object

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

Constructor Detail

IlvTileLockFilter

protected IlvTileLockFilter()

Initializes an instance of IlvTileLockFilter

Method Detail

isLockAllowed

public abstract boolean isLockAllowed(IlvTileController tileController,
                                      IlvManagerView view)

Returns true if an event in view can lock a tile in the specified tile controller (If the tile controller is attached to a layer, this function is called only if the layer is visible in the view).

Parameters:

tileController - the controller of the tiles

view - the view that requested the lock (after a zoom operation or a resize operation for instance)

isPersistent

public abstract boolean isPersistent()

Tells if the filter must be saved to an IVL file. If this method returns true, the filter is saved; otherwise it is not saved.

write

public void write(IlvOutputStream stream)
           throws IOException

Writes the filter to an IlvOutputStream.

Specified by:

write in interface IlvPersistentObject

Parameters:

stream - the output stream. You must override this method if specific data is to be stored. Note that the first instruction in your implementation of the method must be super.write(stream).

Throws:

IOException - standard IO error.