Package org.apache.sis.internal.coverage.j2d

Class BatchComputedImage

java.lang.Object

org.apache.sis.image.PlanarImage

org.apache.sis.image.ComputedImage

org.apache.sis.internal.coverage.j2d.BatchComputedImage

All Implemented Interfaces:

RenderedImage, Disposable

Direct Known Subclasses:

TiledDeferredImage

public abstract class BatchComputedImage
extends ComputedImage

A computed image for which it is more efficient to compute tiles in batch instead of one-by-one. This class is useful only when users may prefetch in advance groups of tiles by calls to the ImageProcessor.prefetch(RenderedImage, Rectangle) method.

Caching

Implementations should manage their own cache for avoiding to compute the same tiles many times. The caching mechanism inherited from ComputedImage is less useful here.

Since:

1.2

Version:

1.2

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private final class	BatchComputedImage.Rasters	The set of tiles fetched by a single call to prefetch(Rectangle).

Field Summary

Fields

Modifier and Type	Field	Description
private BatchComputedImage.Rasters	prefetched	Tiles fetched by a calls to prefetch(Rectangle), or null if none.
private final Map<String,Object>	properties	Image properties, or an empty map if none.

Fields inherited from class org.apache.sis.image.ComputedImage

sampleModel, SOURCE_PADDING_KEY

Fields inherited from class org.apache.sis.image.PlanarImage

GRID_GEOMETRY_KEY, MASK_KEY, POSITIONAL_ACCURACY_KEY, SAMPLE_RESOLUTIONS_KEY, STATISTICS_KEY

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BatchComputedImage(SampleModel sampleModel, Map<String,Object> properties, RenderedImage... sources)	Creates an initially empty image with the given sample model.

Method Summary

Modifier and Type	Method	Description
protected final Raster	computeTile(int tileX, int tileY, WritableRaster previous)	Invoked when a single tile need to be computed.
protected abstract Raster[]	computeTiles(Rectangle tiles)	Computes immediately and returns all tiles in the given ranges of tile indices.
Object	getProperty(String key)	Gets a property from this image.
String[]	getPropertyNames()	Returns the names of all recognized properties, or null if this image has no properties.
protected Disposable	prefetch(Rectangle region)	Notifies this image that tiles will be computed soon in the given region.
private void	remove(BatchComputedImage.Rasters tiles)	Discards the given set of tiles.

Methods inherited from class org.apache.sis.image.ComputedImage

clearErrorFlags, createTile, dispose, getSampleModel, getSource, getSources, getTile, getTileHeight, getTileWidth, getWritableTileIndices, hasTileWriters, isTileWritable, markDirtyTiles, markTileWritable, sourceTileChanged

Methods inherited from class org.apache.sis.image.PlanarImage

copyData, getBounds, getData, getData, getMinTileX, getMinTileY, getMinX, getMinY, getNumXTiles, getNumYTiles, getTileGridXOffset, getTileGridYOffset, toString, verify

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.awt.image.RenderedImage

getColorModel, getHeight, getWidth

Field Details

properties

private final Map<String,Object> properties

Image properties, or an empty map if none. May contain instances of DeferredProperty.

prefetched

private BatchComputedImage.Rasters prefetched

Tiles fetched by a calls to prefetch(Rectangle), or null if none. This is a linked list, but the list will rarely have more than 1 element.

Constructor Details

BatchComputedImage

protected BatchComputedImage(SampleModel sampleModel,
 Map<String,Object> properties,
 RenderedImage... sources)

Creates an initially empty image with the given sample model.

Parameters:

sampleModel - the sample model shared by all tiles in this image.

properties - image properties (DeferredProperty supported), or null if none.

sources - sources of this image (may be an empty array), or a null array if unknown.

Method Details

getProperty

public Object getProperty(String key)

Gets a property from this image.

Specified by:

getProperty in interface RenderedImage

Overrides:

getProperty in class PlanarImage

Parameters:

key - the name of the property to get.

Returns:

the property value, or Image.UndefinedProperty if none.

getPropertyNames

public String[] getPropertyNames()

Returns the names of all recognized properties, or null if this image has no properties.

Specified by:

getPropertyNames in interface RenderedImage

Overrides:

getPropertyNames in class PlanarImage

Returns:

names of all recognized properties, or null if none.

computeTiles

protected abstract Raster[] computeTiles(Rectangle tiles)
                                  throws Exception

Computes immediately and returns all tiles in the given ranges of tile indices. Tiles shall be returned in row-major order. It is implementer responsibility to ensure that all rasters have consistent Raster.getMinX()/getMinY() values.

Parameters:

tiles - range of tile indices for which to precompute tiles.

Returns:

precomputed tiles for the given indices, in row-major fashion.

Throws:

Exception - if an error occurred when computing tiles.

computeTile

protected final Raster computeTile(int tileX,
 int tileY,
 WritableRaster previous)
                            throws Exception

Invoked when a single tile need to be computed. This method first searches for the tile in the regions prepared by calls to prefetch(Rectangle). If the requested tile is not already fetched, then this method delegates to computeTiles(Rectangle).

Specified by:

computeTile in class ComputedImage

Parameters:

tileX - the column index of the tile to compute.

tileY - the row index of the tile to compute.

previous - ignored (this method creates a new raster on each invocation).

Returns:

computed tile for the given indices.

Throws:

Exception - if an error occurred while computing the tile.

prefetch

protected Disposable prefetch(Rectangle region)

Notifies this image that tiles will be computed soon in the given region.

Overrides:

prefetch in class ComputedImage

Parameters:

region - indices of the tiles which will be prefetched.

Returns:

handler on which to invoke dispose() after the prefetch operation.

remove

private void remove(BatchComputedImage.Rasters tiles)

Discards the given set of tiles. This method is invoked when the fetched tiles are no longer needed.

Parameters:

tiles - fetched tiles to removed from the prefetched linked list.