org.esa.beam.framework.dataio
Interface ProductReader

All Known Implementing Classes:

AbstractProductBuilder, AbstractProductReader, OperatorProductReader, ProductFlipper, ProductSubsetBuilder

public interface ProductReader

Classes implementing the ProductReader interface know how to create an in-memory representation of a given data product as input source.

Version:

$Revision$ $Date$

Author:

Norman Fomferra

See Also:

ProductWriter

Method Summary

void	close() Closes the access to all currently opened resources such as file input streams and all resources of this children directly owned by this reader.
Object	getInput() Retrives the current input destination object.
ProductReaderPlugIn	getReaderPlugIn() Returns the plug-in which created this product reader.
ProductSubsetDef	getSubsetDef() Returns the subset information with which this a data product is read from its physical source.
void	readBandRasterData(Band destBand, int destOffsetX, int destOffsetY, int destWidth, int destHeight, ProductData destBuffer, com.bc.ceres.core.ProgressMonitor pm) Reads raster data from the data source specified by the given destination band into the given in-memory buffer and region.
Product	readProductNodes(Object input, ProductSubsetDef subsetDef) Reads a data product and returns a in-memory representation of it.

Method Detail

getReaderPlugIn

ProductReaderPlugIn getReaderPlugIn()

Returns the plug-in which created this product reader.

Returns:

the product reader plug-in, should never be null

getInput

Object getInput()

Retrives the current input destination object. Thie return value might be null if the setInput has not been called so far.

getSubsetDef

ProductSubsetDef getSubsetDef()

Returns the subset information with which this a data product is read from its physical source.

Returns:

the subset information, can be null

readProductNodes

Product readProductNodes(Object input,
                         ProductSubsetDef subsetDef)
                         throws IOException,
                                IllegalFileFormatException

Reads a data product and returns a in-memory representation of it.

The given subset info can be used to specify spatial and spectral portions of the original proudct. If the subset is omitted, the complete product is read in.

Whether the band data - the actual pixel values - is read in immediately or later when pixels are requested, is up to the implementation.

Parameters:

input - an object representing a valid output for this product reader, might be a ImageInputStream or other Object to use for future decoding.

subsetDef - a spectral or spatial subset (or both) of the product. If null, the entire product is read in

Throws:

IllegalArgumentException - if input is null or it's type is not one of the supported input sources.

IOException - if an I/O error occurs

IllegalFileFormatException - if the file format is illegal

readBandRasterData

void readBandRasterData(Band destBand,
                        int destOffsetX,
                        int destOffsetY,
                        int destWidth,
                        int destHeight,
                        ProductData destBuffer,
                        com.bc.ceres.core.ProgressMonitor pm)
                        throws IOException

Reads raster data from the data source specified by the given destination band into the given in-memory buffer and region.

Destination band

The destination band is used to identify the data source from which this method transfers the sample values into the given destination buffer. The method does not modify the given destination band at all. If this product reader has a ProductSubsetDef instance attached to it, the method should also consider the specified spatial subset and sub-sampling (if any) applied to the destination band.

Destination region

The given destination region specified by the destOffsetX, destOffsetY, destWidth and destHeight parameters are given in the band's raster co-ordinates of the raster which results after applying the optional spatial subset and sub-sampling given by the ProductSubsetDef instance to the data source. If no spatial subset and sub-sampling is specified, the destination co-ordinates are identical with the source co-ordinates. The destination region should always specify a sub-region of the band's scene raster.

Destination buffer

The first element of the destination buffer corresponds to the given destOffsetX and destOffsetY of the destination region. The offset parameters are not an offset within the buffer.
The number of elements in the buffer exactly be destWidth * destHeight. The pixel values read are stored in line-by-line order, so the raster X co-ordinate varies faster than the Y co-ordinate.

Parameters:

destBand - the destination band which identifies the data source from which to read the sample values

destOffsetX - the X-offset in the band's raster co-ordinates

destOffsetY - the Y-offset in the band's raster co-ordinates

destWidth - the width of region to be read given in the band's raster co-ordinates

destHeight - the height of region to be read given in the band's raster co-ordinates

destBuffer - the destination buffer which receives the sample values to be read

Throws:

IOException - if an I/O error occurs

IllegalArgumentException - if the number of elements destination buffer not equals destWidth * destHeight or the destination region is out of the band's scene raster

See Also:

RasterDataNode.getSceneRasterWidth(), RasterDataNode.getSceneRasterHeight()

close

void close()
           throws IOException

Closes the access to all currently opened resources such as file input streams and all resources of this children directly owned by this reader. Its primary use is to allow the garbage collector to perform a vanilla job.

This method should be called only if it is for sure that this object instance will never be used again. The results of referencing an instance of this class after a call to close() are undefined.

Overrides of this method should always call super.close(); after disposing this instance.

Throws:

IOException - if an I/O error occurs