ilog.views.chart.data.lod

Class IlvDataTileController

java.lang.Object

ilog.views.chart.data.lod.IlvDataTileController

public class IlvDataTileController
extends Object

This class implements a one-dimensional load-on-demand mechanism. It divides the x-axis into a number of equal intervals called tiles. Each time a tile becomes visible due to a change in the visible range of an x-axis, the tile controller notifies a loader (called tile loader) to load the data attached to this tile.

Loaded tiles that are not displayed by any chart are put in a cache (called tile cache) for quick access.

Every change in data tile status is notified by DataTileEvent events that are sent to all the subscribed DataTileListener listeners.

Every instance of IlvDataTileController can be associated to only one IlvLODDataSet.

This class is multithread-safe.

Since:

JViews 5.0

See Also:

IlvDataTileLoader, IlvDataTileCache, IlvDataTile

Constructor Summary

Constructors

Constructor and Description
IlvDataTileController(IlvDataTileLoader loader, IlvDataTileCache cache, double tileOrigin, double tileLength, int tileCapacity) Creates a new controller with the specified tile loader.

Method Summary

Modifier and Type	Method and Description
void	addDataTileListener(DataTileListener listener) Adds a listener that will be notified of changes in tile status.
void	dispose() Stops the load-on-demand mechanism.
IlvDataTileCache	getCache() Returns the cache used by the controller.
IlvLODDataSet	getDataSet() Returns the data set associated with the controller.
IlvDataTileLoader	getLoader() Returns the data tile loader.
int	getTileCapacity() Returns the capacity of the tile.
int[]	getTileIndices(IlvDataInterval range) Returns the indices of the tiles intersecting a given range.
double	getTileLength() Returns the length of the tiles intervals.
double	getTileOrigin() Returns the origin used to compute the tiles intervals.
boolean	isActive() Indicates whether the controller is in activity.
boolean	isLoadingInCache() Indicates whether tiles whose loading is not complete are put in the cache or released.
void	removeDataTileListener(DataTileListener listener) Removes the specified listener.
void	requestLoading(IlvDataInterval range, Object req) Requests the loading of data according to the specified range.
void	setActive(boolean active) Specifies whether the controller is active.
void	setLoadingInCache(boolean load) Specifies whether tiles whose loading is not complete are put in the cache or released.
void	unlockTiles(Object lock) Unlocks all the tiles locked by the specified object.

Methods inherited from class java.lang.Object

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

Constructor Detail

IlvDataTileController

public IlvDataTileController(IlvDataTileLoader loader,
                             IlvDataTileCache cache,
                             double tileOrigin,
                             double tileLength,
                             int tileCapacity)

Creates a new controller with the specified tile loader. Tiles will be created and loaded on-demand according to the specified tile origin and tile length.

Parameters:

loader - The object that will load the data into new tiles.

cache - The object that implements the strategy for caching/releasing the tiles.

tileOrigin - The starting x-value of the first tile.

tileLength - The length of a tile along the x-axis.

tileCapacity - The capacity of a tile. This number represents the maximum number of data points a tile can hold. This capacity is used by the controller to provide indexed access to data points.

Method Detail

getLoader

public final IlvDataTileLoader getLoader()

Returns the data tile loader. The loader is specified in the controller constructor and cannot be changed afterwards.

getCache

public IlvDataTileCache getCache()

Returns the cache used by the controller. The cache is specified in the controller constructor and cannot be changed afterwards.

getTileOrigin

public double getTileOrigin()

Returns the origin used to compute the tiles intervals. This origin is specified in the controller constructor and cannot be changed afterwards.

getTileLength

public double getTileLength()

Returns the length of the tiles intervals. This length is specified in the controller constructor and cannot be changed afterwards.

getTileCapacity

public final int getTileCapacity()

Returns the capacity of the tile. This capacity is specified in the controller constructor and cannot be changed afterwards.

getDataSet

public final IlvLODDataSet getDataSet()

Returns the data set associated with the controller. There is a one-to-one relationship between a load-on-demand data set and its controller. This association is done when creating the data set.

isLoadingInCache

public final boolean isLoadingInCache()

Indicates whether tiles whose loading is not complete are put in the cache or released.

See Also:

setLoadingInCache(boolean)

setLoadingInCache

public void setLoadingInCache(boolean load)

Specifies whether tiles whose loading is not complete are put in the cache or released.

The default value of this property is false.

Parameters:

load - If true, a tile that is not yet fully loaded will be stored in the cache, where the loading can be completed. If set to false, the tile will be discarded and the loading canceled.

See Also:

isLoadingInCache()

isActive

public final boolean isActive()

Indicates whether the controller is in activity.

See Also:

setActive(boolean)

setActive

public void setActive(boolean active)

Specifies whether the controller is active. This method allows you to temporarily switch off the load-on-demand mechanism.

See Also:

isActive()

addDataTileListener

public void addDataTileListener(DataTileListener listener)

Adds a listener that will be notified of changes in tile status.

removeDataTileListener

public void removeDataTileListener(DataTileListener listener)

Removes the specified listener.

getTileIndices

public int[] getTileIndices(IlvDataInterval range)

Returns the indices of the tiles intersecting a given range.

Parameters:

range - The range.

Returns:

An array containing the indices of the tiles intersecting the range.

unlockTiles

public void unlockTiles(Object lock)

Unlocks all the tiles locked by the specified object. A tile that is no longer locked will be put in the cache.

requestLoading

public void requestLoading(IlvDataInterval range,
                           Object req)

Requests the loading of data according to the specified range.

If a chart displays a load-on-demand data set associated with the controller, this method is automatically called when the visible range of the x-axis of this chart changes. You can also use this method to explicitly query the loading of data that are not displayed by any chart. In this case, an object is associated with the request, and used to lock the corresponding data tiles. Once the loaded data is no more needed, the unlockTiles(Object) should be used to release these tiles.

Parameters:

range - The range for which data should be loaded.

req - The object that performs the request. This object will be used as a lock on the tiles.

dispose

public void dispose()

Stops the load-on-demand mechanism. This method releases all the loaded and cached tiles.

Since:

JViews 8.5