public class FileTileCache extends Object implements javax.media.jai.TileCache
TileCache
provides a mechanism by which an
OpImage
may cache its computed tiles. There may be
multiple TileCache
s used in an application up to the
point of having a different TileCache
for each
OpImage
.
The TileCache
used for a particular OpImage
is derived from the RenderingHints
assigned to the
associated imaging chain node. If the node is constructed using
JAI.create()
and no TileCache
is specified
in the RenderingHints
parameter, then one is derived
from the RenderingHints
associated with the instance of the
JAI
class being used.
In the Sun reference implementation, the cache size is limited by
the memory capacity, which is set to a default value at construction
or subsequently using the setMemoryCapacity()
method.
The initial value may be obtained using getMemoryCapacity()
.
The tile capacity is not used as different images may have very different
tile sizes so that this metric is not a particularly meaningful control
of memory resource consumption in general.
JAI
,
RenderedOp
,
RenderingHints
Constructor and Description |
---|
FileTileCache(File cacheDir) |
Modifier and Type | Method and Description |
---|---|
void |
add(RenderedImage owner,
int tileX,
int tileY,
Raster tile)
Adds a tile to the cache.
|
void |
add(RenderedImage owner,
int tileX,
int tileY,
Raster tile,
Object tileCacheMetric)
Adds a tile to the cache with an associated compute cost
|
void |
addTiles(RenderedImage owner,
Point[] tileIndices,
Raster[] tiles,
Object tileCacheMetric)
Adds an array of tiles to the tile cache.
|
void |
flush()
Advises the cache that all of its tiles may be discarded.
|
long |
getMemoryCapacity()
Returns the memory capacity in bytes.
|
float |
getMemoryThreshold()
Returns the memory threshold, which is the fractional
amount of cache memory to retain during tile removal.
|
Raster |
getTile(RenderedImage owner,
int tileX,
int tileY)
Retrieves a tile.
|
int |
getTileCapacity()
Deprecated.
as of JAI 1.1.
|
Comparator |
getTileComparator()
Returns the
Comparator currently set for use in ordering
the CachedTile s stored by the TileCache . |
Raster[] |
getTiles(RenderedImage owner)
Retrieves an array of all tiles in the cache which are owned by the
specified image.
|
Raster[] |
getTiles(RenderedImage owner,
Point[] tileIndices)
Returns an array of tile
Raster s from the cache. |
void |
memoryControl()
Advises the cache that some of its tiles may be discarded.
|
void |
remove(RenderedImage owner,
int tileX,
int tileY)
Advises the cache that a tile is no longer needed.
|
void |
removeTiles(RenderedImage owner)
Advises the cache that all tiles associated with a given image
are no longer needed.
|
void |
setMemoryCapacity(long memoryCapacity)
Sets the memory capacity to a desired number of bytes.
|
void |
setMemoryThreshold(float memoryThreshold)
Sets the
memoryThreshold value to a floating
point number that ranges from 0.0 to 1.0. |
void |
setTileCapacity(int tileCapacity)
Deprecated.
as of JAI 1.1.
|
void |
setTileComparator(Comparator comparator)
Sets a
Comparator which imposes an order on the
CachedTile s stored in the TileCache . |
public FileTileCache(File cacheDir)
public void add(RenderedImage owner, int tileX, int tileY, Raster tile)
add
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileX
- The X index of the tile in the owner's tile grid.tileY
- The Y index of the tile in the owner's tile grid.tile
- A Raster
containing the tile data.public void add(RenderedImage owner, int tileX, int tileY, Raster tile, Object tileCacheMetric)
add
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileX
- The X index of the tile in the owner's tile grid.tileY
- The Y index of the tile in the owner's tile grid.tile
- A Raster
containing the tile data.tileCacheMetric
- An Object
as a tile metric.public void addTiles(RenderedImage owner, Point[] tileIndices, Raster[] tiles, Object tileCacheMetric)
addTiles
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileIndices
- An array of Point
s containing the
tileX
and tileY
indices for each tile.tiles
- The array of tile Raster
s containing tile data.tileCacheMetric
- Object which provides an ordering metric
associated with the RenderedImage
owner.public Raster getTile(RenderedImage owner, int tileX, int tileY)
null
if the tile is not
present in the cache.getTile
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileX
- The X index of the tile in the owner's tile grid.tileY
- The Y index of the tile in the owner's tile grid.public Raster[] getTiles(RenderedImage owner)
getTiles
in interface javax.media.jai.TileCache
owner
- The RenderedImage
to which the tiles belong.null
if there are none currently in the cache.public Raster[] getTiles(RenderedImage owner, Point[] tileIndices)
Raster
s from the cache.
Any or all of the elements of the returned array may be
null
if the corresponding tile is not in the cache.
The length of the returned array must be the same as that of the
parameter array and the ith Raster
in the
returned array must correspond to the ith tile index in
the parameter array.getTiles
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileIndices
- An array of Point
s containing the
tileX
and tileY
indices for each tile.public void removeTiles(RenderedImage owner)
removeTiles
in interface javax.media.jai.TileCache
owner
- The RenderedImage
owner of the tiles
to be removed.public void remove(RenderedImage owner, int tileX, int tileY)
remove
in interface javax.media.jai.TileCache
owner
- The RenderedImage
that the tile belongs to.tileX
- The X index of the tile in the owner's tile grid.tileY
- The Y index of the tile in the owner's tile grid.public void flush()
flush
in interface javax.media.jai.TileCache
public void memoryControl()
memoryControl
in interface javax.media.jai.TileCache
public void setTileCapacity(int tileCapacity)
setTileCapacity
in interface javax.media.jai.TileCache
tileCapacity
- The new capacity, in tiles.public int getTileCapacity()
getTileCapacity
in interface javax.media.jai.TileCache
public void setMemoryCapacity(long memoryCapacity)
TileCache
's memory usage is less than
memoryCapacity
.setMemoryCapacity
in interface javax.media.jai.TileCache
memoryCapacity
- The new capacity, in bytes.public long getMemoryCapacity()
getMemoryCapacity
in interface javax.media.jai.TileCache
public void setMemoryThreshold(float memoryThreshold)
memoryThreshold
value to a floating
point number that ranges from 0.0 to 1.0.
When the cache memory is full, the memory
usage will be reduced to this fraction of
the total cache memory capacity. For example,
a value of .75 will cause 25% of the memory
to be cleared, while retaining 75%.setMemoryThreshold
in interface javax.media.jai.TileCache
memoryThreshold
- Retained fraction of memoryIllegalArgumentException
- if the memoryThreshold
is less than 0.0 or greater than 1.0public float getMemoryThreshold()
getMemoryThreshold
in interface javax.media.jai.TileCache
public void setTileComparator(Comparator comparator)
Comparator
which imposes an order on the
CachedTile
s stored in the TileCache
.
This ordering is used in memoryControl()
to determine
the sequence in which tiles will be removed from the
TileCache
so as to reduce the memory to the level given
by the memory threshold. The Object
s passed to the
compare()
method of the Comparator
will
be instances of CachedTile
. CachedTile
s
will be removed from the TileCache
in the ascending
order imposed by this Comparator
. If no
Comparator
is currently set, the TileCache
should use an implementation-dependent default ordering. In the
Sun Microsystems, Inc., implementation of TileCache
,
this ordering is the least recently used
ordering, i.e., the tiles least recently used will be removed first
by memoryControl()
.setTileComparator
in interface javax.media.jai.TileCache
comparator
- A Comparator
which orders the
CachedTile
s stored by the TileCache
;
if null
an implementation-dependent algorithm
will be used.public Comparator getTileComparator()
Comparator
currently set for use in ordering
the CachedTile
s stored by the TileCache
.getTileComparator
in interface javax.media.jai.TileCache
Comparator
or null
if the
implementation-dependent ordering algorithm is being used.Copyright © 2014–2017 European Space Agency (ESA). All rights reserved.