ncsa.hdf.object.fits
Class FitsDatatype

java.lang.Object
  ncsa.hdf.object.HObject
      ncsa.hdf.object.Datatype
          ncsa.hdf.object.fits.FitsDatatype

All Implemented Interfaces:

java.io.Serializable, DataFormat

public class FitsDatatype
extends Datatype

Datatype encapsulates information of a datatype. Information includes the class, size, endian of a datatype.

Version:

1.1 9/4/2007

Author:

Peter X. Cao

See Also:

Serialized Form

Field Summary

static long

serialVersionUID

Fields inherited from class ncsa.hdf.object.Datatype

CLASS_ARRAY, CLASS_BITFIELD, CLASS_CHAR, CLASS_COMPOUND, CLASS_ENUM, CLASS_FLOAT, CLASS_INTEGER, CLASS_NO_CLASS, CLASS_OPAQUE, CLASS_REFERENCE, CLASS_STRING, CLASS_VLEN, NATIVE, NSGN, ORDER_BE, ORDER_LE, ORDER_NONE, ORDER_VAX, SIGN_2, SIGN_NONE

Fields inherited from class ncsa.hdf.object.HObject

separator

Constructor Summary

FitsDatatype(int theType)
Create a Datatype with a given fits native datatype.

FitsDatatype(int tclass, int tsize, int torder, int tsign)
Create an Datatype with specified class, size, byte order and sign.

Method Summary

static java.lang.Object	allocateArray(int dtype, int size) Allocate an one-dimensional array of byte, short, int, long, float, double, or String to store data retrieved from an fits file based on the given fits datatype and dimension sizes.
void	close(int id) Closes a datatype identifier.
void	fromNative() Translate fits datatype identifier into FitsDatatype.
void	fromNative(int dtype) Translate fits datatype identifier into FitsDatatype.
java.lang.String	getDatatypeDescription() Returns a short text description of this datatype.
java.util.List	getMetadata(int... attrPropList)
boolean	hasAttribute() Check if the object has any attributes attached.
boolean	isUnsigned() Checks if this datatype is an unsigned integer.
int	toNative() Converts the datatype object to a native datatype.

Methods inherited from class ncsa.hdf.object.Datatype

getBasetype, getDatatypeClass, getDatatypeOrder, getDatatypeSign, getDatatypeSize, getEnumMembers, getMetadata, open, removeMetadata, setEnumMembers, writeMetadata

Methods inherited from class ncsa.hdf.object.HObject

equalsOID, getFID, getFile, getFileFormat, getFullName, getLinkTargetObjName, getName, getOID, getPath, setLinkTargetObjName, setName, setPath, toString

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

FitsDatatype

public FitsDatatype(int tclass,
                    int tsize,
                    int torder,
                    int tsign)

Create an Datatype with specified class, size, byte order and sign. The following list a few example of how to create a Datatype.

1. to create unsigned native integer
   FitsDatatype type = new H5Dataype(CLASS_INTEGER, NATIVE, NATIVE, SIGN_NONE);
2. to create 16-bit signed integer with big endian
   FitsDatatype type = new H5Dataype(CLASS_INTEGER, 2, ORDER_BE, NATIVE);
3. to create native float
   FitsDatatype type = new H5Dataype(CLASS_FLOAT, NATIVE, NATIVE, -1);
4. to create 64-bit double
   FitsDatatype type = new H5Dataype(CLASS_FLOAT, 8, NATIVE, -1);

Parameters:

tclass - the class of the datatype.

tsize - the size of the datatype in bytes.

torder - the order of the datatype.

tsign - the sign of the datatype.

FitsDatatype

public FitsDatatype(int theType)

Create a Datatype with a given fits native datatype.

Parameters:

theType - the fits native datatype.

Method Detail

hasAttribute

public boolean hasAttribute()

Description copied from interface: DataFormat

Check if the object has any attributes attached.

Returns:

true if it has any attribute(s), false otherwise.

allocateArray

public static java.lang.Object allocateArray(int dtype,
                                             int size)
                                      throws java.lang.OutOfMemoryError

Allocate an one-dimensional array of byte, short, int, long, float, double, or String to store data retrieved from an fits file based on the given fits datatype and dimension sizes.

Parameters:

dtype - the fits datatype.

size - the total size of the array.

Returns:

the array object if successful and null otherwise.

Throws:

java.lang.OutOfMemoryError

fromNative

public void fromNative()

Translate fits datatype identifier into FitsDatatype.

fromNative

public void fromNative(int dtype)

Translate fits datatype identifier into FitsDatatype.

Specified by:

fromNative in class Datatype

Parameters:

nativeID - the fits native datatype.

getDatatypeDescription

public java.lang.String getDatatypeDescription()

Description copied from class: Datatype

Returns a short text description of this datatype.

Overrides:

getDatatypeDescription in class Datatype

Returns:

a short text description of this datatype

isUnsigned

public boolean isUnsigned()

Description copied from class: Datatype

Checks if this datatype is an unsigned integer.

Specified by:

isUnsigned in class Datatype

Returns:

true if the datatype is an unsigned integer; otherwise, returns false.

toNative

public int toNative()

Description copied from class: Datatype

Converts the datatype object to a native datatype. Subclasses must implement it so that this datatype will be converted accordingly. Use close() to close the native identifier; otherwise, the datatype will be left open.

For example, a HDF5 datatype created from

 H5Dataype dtype = new H5Datatype(CLASS_INTEGER, 4, NATIVE, SIGN_NONE);
 int tid = dtype.toNative();
 

There "tid" will be the HDF5 datatype id of a 32-bit unsigned integer, which is equivalent to

 int tid = H5.H5Tcopy(HDF5Constants.H5T_NATIVE_UNINT32);
 

Specified by:

toNative in class Datatype

Returns:

the identifier of the native datatype.

close

public void close(int id)

Description copied from class: Datatype

Closes a datatype identifier.

Sub-clases must replace this default implementation.

Specified by:

close in class Datatype

Parameters:

id - the datatype identifier to close.

getMetadata

public java.util.List getMetadata(int... attrPropList)
                           throws java.lang.Exception

Throws:

java.lang.Exception