Package com.bc.ceres.jai.tilecache

Class SwappingTileCache

  • All Implemented Interfaces:
    com.sun.media.jai.util.CacheDiagnostics, javax.media.jai.TileCache
    public final class SwappingTileCache
extends Observable
implements javax.media.jai.TileCache, com.sun.media.jai.util.CacheDiagnostics
    A tile cache based on Sun Microsystems' reference implementation of the javax.media.jai.TileCache interface. In opposite to the Sun implementation, we'll never throw away any tiles but instead swap them to a SwapSpace.

    • Field Detail

      • DEFAULT_MEMORY_CAPACITY

        public static final long DEFAULT_MEMORY_CAPACITY
        The default memory capacity of the cache (16 MB).
        See Also:
        Constant Field Values

      • DEFAULT_HASHTABLE_CAPACITY

        public static final int DEFAULT_HASHTABLE_CAPACITY
        The default hashtable capacity (heuristic)
        See Also:
        Constant Field Values

      • DEFAULT_SWAP_DIR

        public static final File DEFAULT_SWAP_DIR
        The default directory where tiles are stored if they don't fit into memory anymore.

    • Constructor Detail

      • SwappingTileCache

        public SwappingTileCache()
        No args constructor. Use the DEFAULT_MEMORY_CAPACITY of 16 Megs.

      • SwappingTileCache

        public SwappingTileCache​(long memoryCapacity,
                         SwapSpace swapSpace)
        Constructor. The memory capacity should be explicitly specified.
        Parameters:
        memoryCapacity - The maximum cache memory size in bytes.
        swapSpace - The space used to swap out tiles.
        Throws:
        IllegalArgumentException - If memoryCapacity is less than 0.

    • Method Detail

      • getCachedTileActions

        public static javax.media.jai.EnumeratedParameter[] getCachedTileActions()
        Returns:
        An array of EnumeratedParameters corresponding to the numeric values returned by the getAction() method of the CachedTile implementation used by SunTileCache. The "name" of each EnumeratedParameter provides a brief string describing the numeric action value.

      • add

        public void add​(RenderedImage owner,
                int tileX,
                int tileY,
                Raster tile)
        Adds a tile to the cache.

        If the specified tile is already in the cache, it will not be cached again. If by adding this tile, the cache exceeds the memory capacity, older tiles in the cache are removed to keep the cache memory usage under the specified limit.

        Specified by:
        add in interface javax.media.jai.TileCache
        Parameters:
        owner - The image the tile blongs to.
        tileX - The tile's X index within the image.
        tileY - The tile's Y index within the image.
        tile - The tile to be cached.

      • add

        public void add​(RenderedImage owner,
                int tileX,
                int tileY,
                Raster tile,
                Object tileCacheMetric)
        Adds a tile to the cache with an associated tile compute cost.

        If the specified tile is already in the cache, it will not be cached again. If by adding this tile, the cache exceeds the memory capacity, older tiles in the cache are removed to keep the cache memory usage under the specified limit.

        Specified by:
        add in interface javax.media.jai.TileCache
        Parameters:
        owner - The image the tile blongs to.
        tileX - The tile's X index within the image.
        tileY - The tile's Y index within the image.
        tile - The tile to be cached.
        tileCacheMetric - Metric for prioritizing tiles

      • addTiles

        public void addTiles​(RenderedImage owner,
                     Point[] tileIndices,
                     Raster[] tiles,
                     Object tileCacheMetric)
        Adds an array of tiles to the tile cache.
        Specified by:
        addTiles in interface javax.media.jai.TileCache
        Parameters:
        owner - The RenderedImage that the tile belongs to.
        tileIndices - An array of Points containing the tileX and tileY indices for each tile.
        tiles - The array of tile Rasters containing tile data.
        tileCacheMetric - Object which provides an ordering metric associated with the RenderedImage owner.
        Since:
        1.1

      • remove

        public void remove​(RenderedImage owner,
                   int tileX,
                   int tileY)
        Removes a tile from the cache.

        If the specified tile is not in the cache, this method does nothing.

        Specified by:
        remove in interface javax.media.jai.TileCache

      • removeTiles

        public void removeTiles​(RenderedImage owner)
        Removes all the tiles that belong to a RenderedImage from the cache.
        Specified by:
        removeTiles in interface javax.media.jai.TileCache
        Parameters:
        owner - The image whose tiles are to be removed from the cache.

      • getTile

        public Raster getTile​(RenderedImage owner,
                      int tileX,
                      int tileY)
        Retrieves a tile from the cache.

        If the specified tile is not in the cache, this method returns null. If the specified tile is in the cache, its last-access time is updated.

        Specified by:
        getTile in interface javax.media.jai.TileCache
        Parameters:
        owner - The image the tile blongs to.
        tileX - The tile's X index within the image.
        tileY - The tile's Y index within the image.

      • getTiles

        public Raster[] getTiles​(RenderedImage owner)
        Retrieves a contiguous array of all tiles in the cache which are owned by the specified image. May be null if there were no tiles in the cache. The array contains no null entries.
        Specified by:
        getTiles in interface javax.media.jai.TileCache
        Parameters:
        owner - The RenderedImage to which the tiles belong.
        Returns:
        An array of all tiles owned by the specified image or null if there are none currently in the cache.

      • getTiles

        public Raster[] getTiles​(RenderedImage owner,
                         Point[] tileIndices)
        Returns an array of tile Rasters 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.
        Specified by:
        getTiles in interface javax.media.jai.TileCache
        Parameters:
        owner - The RenderedImage that the tile belongs to.
        tileIndices - An array of Points containing the tileX and tileY indices for each tile.
        Since:
        1.1

      • flush

        public void flush()
        Removes -ALL- tiles from the cache.
        Specified by:
        flush in interface javax.media.jai.TileCache

      • getTileCapacity

        public int getTileCapacity()
        Returns the cache's tile capacity.

        This implementation of TileCache does not use the tile capacity. This method always returns 0.

        Specified by:
        getTileCapacity in interface javax.media.jai.TileCache

      • setTileCapacity

        public void setTileCapacity​(int tileCapacity)
        Sets the cache's tile capacity to the desired number of tiles.

        This implementation of TileCache does not use the tile capacity. The cache size is limited by the memory capacity only. This method does nothing and has no effect on the cache.

        Specified by:
        setTileCapacity in interface javax.media.jai.TileCache
        Parameters:
        tileCapacity - The desired tile capacity for this cache in number of tiles.

      • getMemoryCapacity

        public long getMemoryCapacity()
        Returns the cache's memory capacity in bytes.
        Specified by:
        getMemoryCapacity in interface javax.media.jai.TileCache

      • setMemoryCapacity

        public void setMemoryCapacity​(long memoryCapacity)
        Sets the cache's memory capacity to the desired number of bytes. If the new memory capacity is smaller than the amount of memory currently being used by this cache, tiles are removed from the cache until the memory usage is less than the specified memory capacity.
        Specified by:
        setMemoryCapacity in interface javax.media.jai.TileCache
        Parameters:
        memoryCapacity - The desired memory capacity for this cache in bytes.
        Throws:
        IllegalArgumentException - If memoryCapacity is less than 0.

      • enableDiagnostics

        public void enableDiagnostics()
        Enable Tile Monitoring and Diagnostics
        Specified by:
        enableDiagnostics in interface com.sun.media.jai.util.CacheDiagnostics

      • disableDiagnostics

        public void disableDiagnostics()
        Turn off diagnostic notification
        Specified by:
        disableDiagnostics in interface com.sun.media.jai.util.CacheDiagnostics

      • getCacheTileCount

        public long getCacheTileCount()
        Specified by:
        getCacheTileCount in interface com.sun.media.jai.util.CacheDiagnostics

      • getCacheMemoryUsed

        public long getCacheMemoryUsed()
        Specified by:
        getCacheMemoryUsed in interface com.sun.media.jai.util.CacheDiagnostics

      • getCacheHitCount

        public long getCacheHitCount()
        Specified by:
        getCacheHitCount in interface com.sun.media.jai.util.CacheDiagnostics

      • getCacheMissCount

        public long getCacheMissCount()
        Specified by:
        getCacheMissCount in interface com.sun.media.jai.util.CacheDiagnostics

      • resetCounts

        public void resetCounts()
        Reset hit and miss counters.
        Specified by:
        resetCounts in interface com.sun.media.jai.util.CacheDiagnostics
        Since:
        1.1

      • setMemoryThreshold

        public void setMemoryThreshold​(float mt)
        Set the memory threshold value.
        Specified by:
        setMemoryThreshold in interface javax.media.jai.TileCache
        Since:
        1.1

      • getMemoryThreshold

        public float getMemoryThreshold()
        Returns the current memoryThreshold.
        Specified by:
        getMemoryThreshold in interface javax.media.jai.TileCache
        Since:
        1.1

      • toString

        public String toString()
        Returns a string representation of the class object.
        Overrides:
        toString in class Object

      • getCachedObject

        public Object getCachedObject()
        Returns:
        the Object that represents the actual cache.

      • memoryControl

        public void memoryControl()
        Removes tiles from the cache based on their last-access time (old to new) until the memory usage is memoryThreshold % of that of the memory capacity.
        Specified by:
        memoryControl in interface javax.media.jai.TileCache

      • setTileComparator

        public void setTileComparator​(Comparator c)
        The Comparator is used to produce an ordered list of tiles based on a user defined compute cost or priority metric. This determines which tiles are subject to "ordered" removal during a memory control operation.
        Specified by:
        setTileComparator in interface javax.media.jai.TileCache
        Since:
        1.1

      • getTileComparator

        public Comparator getTileComparator()
        Return the current comparator
        Specified by:
        getTileComparator in interface javax.media.jai.TileCache
        Since:
        1.1

      • dump

        public void dump()