Package gov.nasa.pds.label.object

Class DataObject

java.lang.Object

gov.nasa.pds.label.object.DataObject

Direct Known Subclasses:

ArrayObject, GenericObject, TableObject

public abstract class DataObject
extends Object

Defines a base type for objects within a label.

Field Summary

Fields

Modifier and Type	Field	Description
protected SeekableByteChannel	channel
protected DataObjectLocation	dataObjectLocation
protected File	fileObject
protected String	localIdentifier
protected String	name
protected long	offset
protected URL	parentDir

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DataObject(File parentDir, long offset, long size)
protected	DataObject(File parentDir, File fileObject, long offset, long size)
protected	DataObject(URL parentDir, File fileObject, long offset, long size, DataObjectLocation location)
protected	DataObject(URL parentDir, File fileObject, long offset, long size, DataObjectLocation location, String name)

Method Summary

Modifier and Type	Method	Description
void	closeChannel()	Closes the underlying channel to the data.
SeekableByteChannel	getChannel()	Gets a SeekableByteChannel for accessing the data object.
URL	getDataFile()	Gets a url that refers to the data file for this object.
DataObjectLocation	getDataObjectLocation()
InputStream	getInputStream()	Gets an input stream to the data object.
String	getLocalIdentifier()
String	getName()
long	getOffset()	Gets the offset within the data file where the object data begins.
long	getSize()	Gets the size of the data object within the data file.
void	setDataObjectLocation(DataObjectLocation dataObjectLocation)
void	setLocalIdentifier(String localIdentifier)
void	setName(String name)
protected void	setSize(long newSize)

Methods inherited from class java.lang.Object

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

Field Details

parentDir

protected URL parentDir

fileObject

protected File fileObject

offset

protected long offset

name

protected String name

localIdentifier

protected String localIdentifier

channel

protected SeekableByteChannel channel

dataObjectLocation

protected DataObjectLocation dataObjectLocation

Constructor Details

DataObject

protected DataObject(File parentDir,
 long offset,
 long size)
              throws IOException

Throws:

IOException

DataObject

protected DataObject(File parentDir,
 File fileObject,
 long offset,
 long size)
              throws IOException

Throws:

IOException

DataObject

protected DataObject(URL parentDir,
 File fileObject,
 long offset,
 long size,
 DataObjectLocation location)
              throws IOException,
URISyntaxException

Throws:

IOException

URISyntaxException

DataObject

protected DataObject(URL parentDir,
 File fileObject,
 long offset,
 long size,
 DataObjectLocation location,
 String name)
              throws IOException

Throws:

IOException

Method Details

getDataFile

public URL getDataFile()
                throws MalformedURLException

Gets a url that refers to the data file for this object.

Returns:

a URL for the file containing the data object

Throws:

MalformedURLException

getOffset

public long getOffset()

Gets the offset within the data file where the object data begins.

Returns:

the offset to the data

getSize

public long getSize()

Gets the size of the data object within the data file.

Returns:

the size of the data object, in bytes

setSize

protected void setSize(long newSize)

getInputStream

public InputStream getInputStream()
                           throws IOException

Gets an input stream to the data object. This input stream will read from the first byte in the data object to the last byte within that object. Other bytes outside of the range for the data object will not be accessed.

Returns:

an input stream to the data object

Throws:

FileNotFoundException - if the data file cannot be found

IOException - if there is an error reading the data file

getChannel

public SeekableByteChannel getChannel()
                               throws IOException

Gets a SeekableByteChannel for accessing the data object. The channel is read-only, and represents only the portion of the data file containing the data object. You must remember to call the closeChannel() method once reading of the data is finished.

Returns:

a SeekableByteChannel for reading bytes from the data object

Throws:

IOException - if there is an error reading the data file

closeChannel

public void closeChannel()

Closes the underlying channel to the data.

getName

public String getName()

setName

public void setName(String name)

getDataObjectLocation

public DataObjectLocation getDataObjectLocation()

setDataObjectLocation

public void setDataObjectLocation(DataObjectLocation dataObjectLocation)

getLocalIdentifier

public String getLocalIdentifier()

setLocalIdentifier

public void setLocalIdentifier(String localIdentifier)