Package noaa.coastwatch.io

Class NCCachedGrid

java.lang.Object

noaa.coastwatch.util.MetadataContainer

noaa.coastwatch.util.DataVariable

noaa.coastwatch.util.Grid

noaa.coastwatch.io.CachedGrid

noaa.coastwatch.io.NCCachedGrid

All Implemented Interfaces:

Cloneable, ValueSource

public class NCCachedGrid
extends CachedGrid

The NCCachedGrid class is a cached grid that understands how to read variable data from NetCDF files.

Since:

3.3.0

Author:

Peter Hollemans

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_CACHE_SIZE	Default cache size in bytes.
static final int	DEFAULT_TILE_SIZE	Default tile size in bytes.

Fields inherited from class noaa.coastwatch.io.CachedGrid

accessMode, DEFAULT_MAX_TILES, DEFAULT_TILE_DIMS, READ_ONLY, READ_WRITE, tiling

Fields inherited from class noaa.coastwatch.util.Grid

COL, COLS, ROW, ROWS

Fields inherited from class noaa.coastwatch.util.DataVariable

data, dims, isUnsigned, lookup, unsignedType

Constructor Summary

Constructors

Constructor	Description
NCCachedGrid(Grid grid, NCReader reader)	Constructs a new read-only NetCDF cached grid with the specified properties.
NCCachedGrid(Grid grid, NCReader reader, int[] start)	Constructs a new read-only NetCDF cached grid with the specified properties.
NCCachedGrid(Grid grid, NCReader reader, String ncVarName, int[] start)	Constructs a new read-only NetCDF cached grid with the specified properties.

Method Summary

Modifier and Type	Method	Description
Class	getDataClass()	Gets the data class.
Object	getDataStream()	Gets the cache data stream as an object.
static void	main(String[] argv)	TESTING: Traverses an HDF file's structure and prints out dataset information.
protected TilingScheme.Tile	readTile(TilingScheme.TilePosition pos)	Reads the specified tile.
void	setTileDims(int[] dims)	Creates a new cache where each tile has the specified dimensions.
protected void	writeTile(TilingScheme.Tile tile)	Writes the specified tile.

Methods inherited from class noaa.coastwatch.io.CachedGrid

clearCache, flush, getCoveringPositions, getData, getData, getMaxTiles, getTileDims, getTileSize, getTilingScheme, getValue, getValue, resetCache, setCacheSize, setData, setData, setMaxTiles, setOptimizedCacheSize, setTileSize, setValue, setValue

Methods inherited from class noaa.coastwatch.util.Grid

arraycopy, checkSubset, getNavigation, getSubset, getValue, interpolate, navigate, setNavigation, setValue

Methods inherited from class noaa.coastwatch.util.DataVariable

convertUnits, dispose, format, format, format, getClassBits, getDecimals, getDimensions, getFormat, getLongName, getMissing, getName, getOptimalStride, getRank, getScaling, getStatistics, getStatistics, getStatistics, getStatistics, getUnits, getUnsigned, getValue, getValues, setAccessHint, setFormat, setLongName, setLookup, setMissing, setName, setUnits, setUnsigned, setValue, toString

Methods inherited from class noaa.coastwatch.util.MetadataContainer

clone, getMetadataMap

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_TILE_SIZE

public static final int DEFAULT_TILE_SIZE

Default tile size in bytes.

See Also:

• Constant Field Values

DEFAULT_CACHE_SIZE

public static final int DEFAULT_CACHE_SIZE

Default cache size in bytes.

See Also:

• Constant Field Values

Constructor Details

NCCachedGrid

public NCCachedGrid(Grid grid,
 NCReader reader,
 String ncVarName,
 int[] start)
             throws IOException

Constructs a new read-only NetCDF cached grid with the specified properties. Unchunked NetCDF variables will be given the default tile size, otherwise the tile size is determined from the file.

Parameters:

grid - the grid to use for attributes. In this constructor, the grid name is not used as the NetCDF variable name.

reader - the NetCDF reader data source.

ncVarName - the NetCDF variable name to read data from.

start - the starting coordinates to read data from. This array should have the same rank as the NetCDF variable, and have values filled in for all dimensions _except_ row and column, which should have -1 as the value. The row and column dimensions are assumed to be adjacent to each other and row to be the first dimension, and then column to be the second dimension. For example if the dimensions are [time, level, row, column], then the start array could be [0, 0, -1, -1] to select the first time and level index.

Throws:

IOException - if a problem occurred accessing the NetCDF file.

See Also:

• NCCachedGrid(Grid,NCReader,int[])

NCCachedGrid

public NCCachedGrid(Grid grid,
 NCReader reader,
 int[] start)
             throws IOException

Constructs a new read-only NetCDF cached grid with the specified properties. Unchunked NetCDF variables will be given the default tile size, otherwise the tile size is determined from the file.

Parameters:

grid - the grid to use for attributes.

reader - the NetCDF reader data source.

start - the starting coordinates to read data from. This array should have the same rank as the NetCDF variable, and have values filled in for all dimensions _except_ row and column, which should have -1 as the value. The row and column dimensions are assumed to be adjacent to each other and row to be the first dimension, and then column to be the second dimension. For example if the dimensions are [time, level, row, column], then the start array could be [0, 0, -1, -1] to select the first time and level index.

Throws:

IOException - if a problem occurred accessing the NetCDF file.

NCCachedGrid

public NCCachedGrid(Grid grid,
 NCReader reader)
             throws IOException

Constructs a new read-only NetCDF cached grid with the specified properties. Unchunked NetCDF variables will be given the default tile size, otherwise the tile size is determined from the file. The NetCDF variable named by the grid must have rank 2.

Parameters:

grid - the grid to use for attributes.

reader - the NetCDF reader data source.

Throws:

IOException - if a problem occurred accessing the NetCDF file.

Method Details

getDataClass

public Class getDataClass()

Gets the data class. This method overrides the parent because the data class for an NC cached grid is not available from the data array when needed in some cases.

Overrides:

getDataClass in class DataVariable

Returns:

the Java class of the data array.

getDataStream

public Object getDataStream()

Description copied from class: CachedGrid

Gets the cache data stream as an object. This is useful for classes that read and write cached grids.

Specified by:

getDataStream in class CachedGrid

Returns:

the data stream used for reading and writing data.

setTileDims

public void setTileDims(int[] dims)

Creates a new cache where each tile has the specified dimensions. Only unchunked NetCDF variables may have the tile dimensions set. For chunked variables, the method has no effect.

Overrides:

setTileDims in class CachedGrid

Parameters:

dims - the tile dimensions as [rows, columns].

readTile

protected TilingScheme.Tile readTile(TilingScheme.TilePosition pos)
                              throws IOException

Description copied from class: CachedGrid

Reads the specified tile.

Specified by:

readTile in class CachedGrid

Parameters:

pos - the tile position to read.

Returns:

the tile at the specified position.

Throws:

IOException - if an error occurred reading the tile data.

writeTile

protected void writeTile(TilingScheme.Tile tile)
                  throws IOException

Description copied from class: CachedGrid

Writes the specified tile. The implementation of this method must set the tile to be not dirty upon successfully writing it, or throw an error.

Specified by:

writeTile in class CachedGrid

Parameters:

tile - the tile to write.

Throws:

IOException - if an error occurred writing the tile data.

main

public static void main(String[] argv)
                 throws Exception

TESTING: Traverses an HDF file's structure and prints out dataset information.

Throws:

Exception