edu.umn.cs.spatialHadoop.nasa

Class HDFRecordReader

java.lang.Object

edu.umn.cs.spatialHadoop.nasa.HDFRecordReader

public class HDFRecordReader
extends java.lang.Object

Reads a specific dataset from an HDF file. Upon instantiation, the portion of the HDF file being read is copied to a local directory. After that, the HDF Java library is used to access the file. This class is designed in specific to read an HDF file provided by NASA in their MODIS datasets. It assumes a certain structure and HDF file format and parses the file accordingly.

Author:

Ahmed Eldawy

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	HDFRecordReader.NASAIterator

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DatasetName Configuration for name of the dataset to read from HDF file
static java.lang.String	ProjectorClass The class used to project NASA points upon read
static java.lang.String	SkipFillValue The configuration entry for skipping the fill value

Constructor Summary

Constructors

Constructor and Description
HDFRecordReader(Configuration job, FileSplit split, java.lang.String datasetName, boolean skipFillValue) Initializes the HDF reader to read a specific dataset from the given HDF file.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
NASADataset	createKey()
java.lang.Iterable<NASAShape>	createValue()
static Dataset	findDataset(Group root, java.lang.String datasetName, boolean matchAny)
long	getPos()
float	getProgress()
boolean	next(NASADataset dataset, java.lang.Iterable<NASAShape> value)
protected boolean	nextObject(NASADataset key, NASAShape shape)

Methods inherited from class java.lang.Object

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

Field Detail

DatasetName

public static final java.lang.String DatasetName

Configuration for name of the dataset to read from HDF file

See Also:

Constant Field Values

SkipFillValue

public static final java.lang.String SkipFillValue

The configuration entry for skipping the fill value

See Also:

Constant Field Values

ProjectorClass

public static final java.lang.String ProjectorClass

The class used to project NASA points upon read

See Also:

Constant Field Values

Constructor Detail

HDFRecordReader

public HDFRecordReader(Configuration job,
               FileSplit split,
               java.lang.String datasetName,
               boolean skipFillValue)
                throws java.io.IOException

Initializes the HDF reader to read a specific dataset from the given HDF file.

Parameters:

job - - Job configuration

split - - A file split pointing to the HDF file

datasetName - - Name of the dataset to read (case insensitive)

Throws:

java.lang.Exception

java.io.IOException

Method Detail

findDataset

public static Dataset findDataset(Group root,
                  java.lang.String datasetName,
                  boolean matchAny)

Parameters:

split -

datasetName -

root -

matchAny -

Returns:

nextObject

protected boolean nextObject(NASADataset key,
                 NASAShape shape)
                      throws java.io.IOException

Throws:

java.io.IOException

next

public boolean next(NASADataset dataset,
           java.lang.Iterable<NASAShape> value)
             throws java.io.IOException

Throws:

java.io.IOException

createKey

public NASADataset createKey()

createValue

public java.lang.Iterable<NASAShape> createValue()

getPos

public long getPos()
            throws java.io.IOException

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Throws:

java.io.IOException

getProgress

public float getProgress()
                  throws java.io.IOException

Throws:

java.io.IOException