org.deegree.coverage.raster.cache
Class CacheRasterReader

java.lang.Object
  org.deegree.coverage.raster.io.grid.GridReader
      org.deegree.coverage.raster.io.grid.GridFileReader
          org.deegree.coverage.raster.cache.CacheRasterReader

All Implemented Interfaces:

RasterReader

public class CacheRasterReader
extends GridFileReader

The CacheRasterReader is a grid based caching mechanism for raster readers.

Version:

$Revision: 31644 $, $Date: 2011-08-24 22:27:43 +0200 (Wed, 24 Aug 2011) $

Author:

Rutger Bezema, last edited by: $Author: mschneider $

Field Summary

Fields inherited from class org.deegree.coverage.raster.io.grid.GridReader

infoFile, sampleSize

Constructor Summary

CacheRasterReader(ByteBuffer filledBuffer, int width, int height, File cacheFile, boolean shouldCreateCachefile, RasterDataInfo dataInfo, RasterGeoReference geoReference, RasterCache cache)
Create a cached raster from the given bytebuffer.

CacheRasterReader(RasterReader cachedReader, File cacheFile, RasterCache cache)

Method Summary

long	cacheFileSize()
boolean	canCreateCacheFile()
boolean	canLoad(File filename) Check if the raster reader is able to read the given raster file.
long	clear(boolean deleteCacheFile) Clears all memory buffers and deletes the cache file if requested.
static CacheRasterReader	createFromCache(RasterReader reader, File cacheFile, RasterCache cache) Creates a CachedRasterReader from the given cacheFile.
long	currentApproxMemory()
boolean	deleteCacheFile() Delete the file this cache reader is using.
void	dispose() Signals the reader that it should try to dispose all in memory data.
long	dispose(boolean memoryBuffersAsWell) Causes the cachefile to be written (if existing) and the memory buffers to be set to null.
boolean	equals(Object other)
void	flush() Writes all current in memory byte buffers to the cache file (if existing).
String	getDataLocationId()
RasterGeoReference	getGeoReference()
int	getHeight()
Set<String>	getSupportedFormats()
int	getWidth()
int	hashCode() Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even distribution and is relatively fast.
long	lastReadAccess() Return the current time millis of the last read action.
AbstractRaster	load(File gridFile, RasterIOOptions options) Read the given raster file into an abstract raster.
AbstractRaster	load(InputStream stream, RasterIOOptions options) Read the given input stream into an abstract raster.
protected void	read(int columnId, int rowId, ByteBuffer buffer) Reads the data from the grid.
BufferResult	read(RasterRect rect, ByteBuffer resultBuffer)
boolean	shouldCreateCacheFile()

Methods inherited from class org.deegree.coverage.raster.io.grid.GridFileReader

file, instantiate, leaveStreamOpen, readValuesFromTile

Methods inherited from class org.deegree.coverage.raster.io.grid.GridReader

allocateTileBuffer, canReadTiles, getBytesPerTile, getEnvelope, getIntersectingTiles, getNumberOfTiles, getRasterDataInfo, getTile, getTileColumns, getTileData, getTileEnvelope, getTileId, getTileRasterHeight, getTileRasterWidth, getTileRows, getTilesPerBlob, instantiate, setTilesPerBlob, snapToGrid

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheRasterReader

public CacheRasterReader(ByteBuffer filledBuffer,
                         int width,
                         int height,
                         File cacheFile,
                         boolean shouldCreateCachefile,
                         RasterDataInfo dataInfo,
                         RasterGeoReference geoReference,
                         RasterCache cache)

Create a cached raster from the given bytebuffer.

Parameters:

filledBuffer - with values.

width - of the raster for which this buffer is valid.

height - of the raster for which this buffer is valid.

cacheFile - to use for storage

shouldCreateCachefile - if writing to disk should be enabled.

dataInfo - defining the data

geoReference - of the raster

cache - used.

CacheRasterReader

public CacheRasterReader(RasterReader cachedReader,
                         File cacheFile,
                         RasterCache cache)

Parameters:

cachedReader -

cacheFile -

cache -

Method Detail

createFromCache

public static CacheRasterReader createFromCache(RasterReader reader,
                                                File cacheFile,
                                                RasterCache cache)

Creates a CachedRasterReader from the given cacheFile.

Parameters:

reader - which backs the cache

cacheFile - to instantiate from

cache - manager to use.

Returns:

a CacheRasterReader or null if the cacheFile could not be read.

load

public AbstractRaster load(File gridFile,
                           RasterIOOptions options)
                    throws IOException

Description copied from interface: RasterReader

Read the given raster file into an abstract raster.

Specified by:

load in interface RasterReader

Overrides:

load in class GridFileReader

Returns:

the loaded raster

Throws:

IOException - may be thrown when there is a problem with reading the raster.

read

protected void read(int columnId,
                    int rowId,
                    ByteBuffer buffer)
             throws IOException

Description copied from class: GridReader

Reads the data from the grid.

Overrides:

read in class GridFileReader

Throws:

IOException

read

public BufferResult read(RasterRect rect,
                         ByteBuffer resultBuffer)
                  throws IOException

Specified by:

read in interface RasterReader

Overrides:

read in class GridFileReader

Parameters:

rect - to read.

resultBuffer - to store the result in

Returns:

the read buffer and its domain

Throws:

IOException

clear

public long clear(boolean deleteCacheFile)

Clears all memory buffers and deletes the cache file if requested. Note this method will not write any data to the cachefile.

Parameters:

deleteCacheFile - true if the cache file should be deleted as well.

Returns:

the number of memory bytes freed up after cleaning.

deleteCacheFile

public boolean deleteCacheFile()

Delete the file this cache reader is using.

Returns:

true if this cached reader no longer references an existing file.

canLoad

public boolean canLoad(File filename)

Description copied from interface: RasterReader

Check if the raster reader is able to read the given raster file.

Specified by:

canLoad in interface RasterReader

Overrides:

canLoad in class GridFileReader

Returns:

true if the class can read the raster

getSupportedFormats

public Set<String> getSupportedFormats()

Specified by:

getSupportedFormats in interface RasterReader

Overrides:

getSupportedFormats in class GridFileReader

Returns:

a Set of (image) formats mime/types the implementation is able to read.

load

public AbstractRaster load(InputStream stream,
                           RasterIOOptions options)
                    throws IOException

Description copied from interface: RasterReader

Read the given input stream into an abstract raster.

Specified by:

load in interface RasterReader

Overrides:

load in class GridReader

Returns:

the loaded raster

Throws:

IOException - may be thrown when there is a problem with reading the raster.

shouldCreateCacheFile

public boolean shouldCreateCacheFile()

Specified by:

shouldCreateCacheFile in interface RasterReader

Overrides:

shouldCreateCacheFile in class GridReader

Returns:

true if a cache file should be created for the read raster.

getGeoReference

public RasterGeoReference getGeoReference()

Specified by:

getGeoReference in interface RasterReader

Overrides:

getGeoReference in class GridReader

Returns:

the geo reference of the read raster

getHeight

public int getHeight()

Specified by:

getHeight in interface RasterReader

Overrides:

getHeight in class GridReader

Returns:

the height (in pixels) of the read raster

getWidth

public int getWidth()

Specified by:

getWidth in interface RasterReader

Overrides:

getWidth in class GridReader

Returns:

the width (in pixels) of the read raster

getDataLocationId

public String getDataLocationId()

Specified by:

getDataLocationId in interface RasterReader

Overrides:

getDataLocationId in class GridFileReader

Returns:

a String which identifies this reader for used the data source, for example the file name, or an url.

lastReadAccess

public long lastReadAccess()

Return the current time millis of the last read action. This method is needed for caching.

Returns:

the System.currentTimeMillis() of the last read operation.

currentApproxMemory

public long currentApproxMemory()

Returns:

the current amount of memory this cached reader has on byte buffers.

cacheFileSize

public long cacheFileSize()

Returns:

the size of the cache file on disk.

dispose

public void dispose()

Description copied from interface: RasterReader

Signals the reader that it should try to dispose all in memory data.

Specified by:

dispose in interface RasterReader

Overrides:

dispose in class GridFileReader

dispose

public long dispose(boolean memoryBuffersAsWell)

Causes the cachefile to be written (if existing) and the memory buffers to be set to null.

Parameters:

memoryBuffersAsWell - if true the memorybuffers (the ones which don't have rasterfiles to back them up) will be deleted as well.

Returns:

the amount of freed memory.

flush

public void flush()

Writes all current in memory byte buffers to the cache file (if existing).

canCreateCacheFile

public boolean canCreateCacheFile()

Returns:

true if this reader can create a cachefile for it's in memory buffers.

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even distribution and is relatively fast. It is created from field f as follows:

• boolean -- code = (f ? 0 : 1)
• byte, char, short, int -- code = (int)f
• long -- code = (int)(f ^ (f >>>32))
• float -- code = Float.floatToIntBits(f);
• double -- long l = Double.doubleToLongBits(f); code = (int)(l ^ (l >>> 32))
• all Objects, (where equals( ) calls equals( ) for this field) -- code = f.hashCode( )
• Array -- Apply above rules to each element

Combining the hash code(s) computed above: result = 37 * result + code;

Overrides:

hashCode in class Object

Returns:

(int) ( result >>> 32 ) ^ (int) result;

See Also:

Object.hashCode()