Package noaa.coastwatch.io

Class HDFReader

java.lang.Object

noaa.coastwatch.io.EarthDataReader

noaa.coastwatch.io.HDFReader

All Implemented Interfaces:

HDFSD

Direct Known Subclasses:

ACSPOHDFReader, CWHDFReader, TSHDFReader

public abstract class HDFReader
extends EarthDataReader
implements HDFSD

An HDF reader is an earth data reader that reads HDF format files using the HDF library class. The HDF reader class is abstract -- subclasses handle specific metadata variants.

Since:

3.1.0

Author:

Peter Hollemans

Field Summary

Fields

Modifier and Type	Field	Description
protected int	sdid	HDF file id.

Fields inherited from class noaa.coastwatch.io.EarthDataReader

dataProjection, info, rawMetadataMap, variables

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	HDFReader(String file)	Constructs an HDF reader from the specified file.
protected	HDFReader(HDFWriter writer)	Constructs an HDF reader from the specified HDF writer.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the reader and frees any resources.
static Object	getAttribute(int sdid, int index)	Gets an HDF attribute value.
static Object	getAttribute(int sdid, String name)	Gets an HDF attribute value.
static Object	getAttributeAsArray(int sdid, int index)	Gets an HDF attribute value.
static Object	getAttributeAsArray(int sdid, String name)	Gets an HDF attribute value.
static void	getAttributes(int sdid, List attList, Map attMap)	Gets a number of attributes specified by a list of name and stores them in a map.
static void	getAttributes(int sdid, Map map, boolean global)	Gets all attributes and stores them in a map.
static int[]	getChunkLengths(int sdsid)	Gets the chunk lengths for a chunked SDS HDF variable.
ChunkProducer	getChunkProducer(String name)	Creates a chunk producer for the specified variable.
static Class	getClass(int type)	Gets the Java primitive class associated with an HDF type.
String	getFilename()	Gets the HDF scientific dataset file name.
protected abstract EarthDataInfo	getGlobalInfo()	Reads the earth data info metadata.
protected DataVariable	getPreviewImpl(int index)	Implementation for the subclass.
int	getSDID()	Gets the HDF scientific dataset ID.
static boolean	getUnsigned(int type)	Determines if the HDF datatype is unsigned.
DataVariable	getVariable(int index)	Creates a data variable object.
static int[]	getVariableDimensions(int sdid, String varName)
static String[]	getVariableNames(int sdid)	Gets an array of HDF dataset variable names.
protected boolean	readAllMetadata()	Determines if the full set of attributes should be read into the global EarthDataInfo object and DataVariable objects.

Methods inherited from class noaa.coastwatch.io.EarthDataReader

canUpdateNavigation, containsVariable, finalize, findVariable, getAllGrids, getAllVariables, getCoordinateSystems, getDataFormat, getIndex, getInfo, getName, getPreview, getPreview, getRawMetadata, getRawMetadata, getSceneTime, getSource, getStatistics, getStatisticsVariables, getVariable, getVariables, getVariablesForSystem, putStatistics, setDataProjection, setUnitsMap, updateNavigation

Methods inherited from class java.lang.Object

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

Field Details

sdid

protected int sdid

HDF file id.

Constructor Details

HDFReader

protected HDFReader(HDFWriter writer)
             throws hdf.hdflib.HDFException,
IOException,
NoninvertibleTransformException,
ClassNotFoundException

Constructs an HDF reader from the specified HDF writer.

Parameters:

writer - the writer to use for reading.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

IOException - if an error occurred reading the file metadata.

NoninvertibleTransformException - if the earth transform object could not be initialized.

ClassNotFoundException - if the HDF attribute type is unknown.

HDFReader

protected HDFReader(String file)
             throws IOException

Constructs an HDF reader from the specified file.

Parameters:

file - the file name to read.

Throws:

IOException - if an error opening or reading the file metadata.

Method Details

getSDID

public int getSDID()

Description copied from interface: HDFSD

Gets the HDF scientific dataset ID.

Specified by:

getSDID in interface HDFSD

getFilename

public String getFilename()

Description copied from interface: HDFSD

Gets the HDF scientific dataset file name.

Specified by:

getFilename in interface HDFSD

getVariableNames

public static String[] getVariableNames(int sdid)
                                 throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets an array of HDF dataset variable names.

Parameters:

sdid - the HDF dataset to read.

Returns:

the array of variable names.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getGlobalInfo

protected abstract EarthDataInfo getGlobalInfo()
                                        throws hdf.hdflib.HDFException,
IOException,
NoninvertibleTransformException,
ClassNotFoundException

Reads the earth data info metadata.

Returns:

the earth data info object.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

IOException - if an error occurred reading the file metadata.

NoninvertibleTransformException - if the earth transform object could not be initialized.

ClassNotFoundException - if the HDF attribute type is unknown.

readAllMetadata

protected boolean readAllMetadata()

Determines if the full set of attributes should be read into the global EarthDataInfo object and DataVariable objects. Generally this is only desirable if the HDF metadata in the data source is compatible with the intended HDF data sink. By default, this method returns false unless overridden in the child class.

Returns:

true if full metadata should be read, or false if not.

getClass

public static Class getClass(int type)
                      throws ClassNotFoundException

Gets the Java primitive class associated with an HDF type.

Parameters:

type - the HDF data type.

Returns:

the Java primitive class.

Throws:

ClassNotFoundException - if a class cannot be found that matches the HDF type.

getUnsigned

public static boolean getUnsigned(int type)

Determines if the HDF datatype is unsigned.

Parameters:

type - the HDF type.

Returns:

true if the type is unsigned, false otherwise.

getAttribute

public static Object getAttribute(int sdid,
 String name)
                           throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets an HDF attribute value.

Parameters:

sdid - the HDF scientific dataset ID.

name - the attribute name.

Returns:

the attribute value. If the attribute is a character string, a Java String is returned. If the attribute has one value only, a Java object will be returned wrapping the primitive type. If the attribute has more than one value, a Java primitive array is returned.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getAttributeAsArray

public static Object getAttributeAsArray(int sdid,
 String name)
                                  throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets an HDF attribute value.

Parameters:

sdid - the HDF scientific dataset ID.

name - the attribute name.

Returns:

the attribute data as an array of Java primitives.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getAttributeAsArray

public static Object getAttributeAsArray(int sdid,
 int index)
                                  throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets an HDF attribute value.

Parameters:

sdid - the HDF scientific dataset ID.

index - the attribute index.

Returns:

the attribute data as an array of Java primitives.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getAttribute

public static Object getAttribute(int sdid,
 int index)
                           throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets an HDF attribute value.

Parameters:

sdid - the HDF scientific dataset ID.

index - the attribute index.

Returns:

the attribute value. If the attribute is a character string, a Java String is returned. If the attribute has one value only, a Java object will be returned wrapping the primitive type. If the attribute has more than one value, a Java primitive array is returned.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getAttributes

public static void getAttributes(int sdid,
 List attList,
 Map attMap)
                          throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets a number of attributes specified by a list of name and stores them in a map.

Parameters:

sdid - the HDF scientific dataset or variable ID for reading.

attList - the list of attribute names to store.

attMap - the attribute map for storing attribute values (modified). If an attribute value cannot be found for the attribute name, no attribute value is stored.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getAttributes

public static void getAttributes(int sdid,
 Map map,
 boolean global)
                          throws hdf.hdflib.HDFException,
ClassNotFoundException

Gets all attributes and stores them in a map.

Parameters:

sdid - the HDF scientific dataset or variable ID for reading.

map - the attribute map.

global - set to true if the HDF attributes are global. If false, it is assumed that the attributes belong to an HDF variable.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

ClassNotFoundException - if the HDF attribute type is unknown.

getPreviewImpl

protected DataVariable getPreviewImpl(int index)
                               throws IOException

Description copied from class: EarthDataReader

Implementation for the subclass.

Specified by:

getPreviewImpl in class EarthDataReader

Throws:

IOException

See Also:

• EarthDataReader.getPreview(int)

getChunkProducer

public ChunkProducer getChunkProducer(String name)
                               throws IOException

Description copied from class: EarthDataReader

Creates a chunk producer for the specified variable.

Overrides:

getChunkProducer in class EarthDataReader

Parameters:

name - the variable name.

Returns:

a chunk producer for the specified variable.

Throws:

IOException

getVariable

public DataVariable getVariable(int index)
                         throws IOException

Description copied from class: EarthDataReader

Creates a data variable object. The full data is read into the object.

Specified by:

getVariable in class EarthDataReader

Parameters:

index - the index of the variable to get. Indexing starts at 0.

Returns:

a data variable object with full data value array.

Throws:

IOException - if the data source had I/O errors.

See Also:

• EarthDataReader.getPreview(int)

getChunkLengths

public static int[] getChunkLengths(int sdsid)
                             throws hdf.hdflib.HDFException

Gets the chunk lengths for a chunked SDS HDF variable.

Parameters:

sdsid - the HDF SDS variable ID.

Returns:

the chunk lengths, one for each dimension or null if the variable is not chunked.

Throws:

hdf.hdflib.HDFException - if an HDF error occurred.

close

public void close()
           throws IOException

Description copied from class: EarthDataReader

Closes the reader and frees any resources.

Specified by:

close in class EarthDataReader

Throws:

IOException - if the data source had I/O errors.

getVariableDimensions

public static int[] getVariableDimensions(int sdid,
 String varName)
                                   throws hdf.hdflib.HDFException

Throws:

hdf.hdflib.HDFException