Module org.hdfgroup.object

Package hdf.object

Class Datatype

Object

hdf.object.HObject

hdf.object.Datatype

All Implemented Interfaces:

MetaDataContainer, Serializable

Direct Known Subclasses:

FitsDatatype, H4Datatype, H5Datatype, NC2Datatype

public abstract class Datatype
extends HObject
implements MetaDataContainer

Datatype is an abstract class that defines datatype characteristics and APIs for a data type. A datatype has four basic characteristics: class, size, byte order and sign. These characteristics are defined in the See HDF5 Datatypes in HDF5 User Guide These characteristics apply to all the sub-classes. The sub-classes may have different ways to describe a datatype. We here define the native datatype to the datatype used by the sub-class. For example, H5Datatype uses a datatype identifier (hid_t) to specify a datatype. NC2Datatype uses ucar.nc2.DataType object to describe its datatype. "Native" here is different from the "native" definition in the HDF5 library. Two functions, createNative() and fromNative(), are defined to convert the general characteristics to/from the native datatype. Sub-classes must implement these functions so that the conversion will be done correctly. The values of the CLASS member are not identical to HDF5 values for a datatype class.

Version:

1.1 9/4/2007

Author:

Peter X. Cao

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected long[]	arrayDims	The dimensions of the ARRAY element of an ARRAY datatype.
protected Datatype	baseType	The base datatype of this datatype (null if this datatype is atomic).
static final int	CLASS_ARRAY	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_BITFIELD	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_CHAR	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_COMPOUND	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_ENUM	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_FLOAT	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_INTEGER	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_NO_CLASS	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_OPAQUE	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_REFERENCE	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_STRING	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_TIME	See HDF5 Datatypes in HDF5 User Guide
static final int	CLASS_VLEN	See HDF5 Datatypes in HDF5 User Guide
protected List<String>	compoundMemberNames	The list of names of members of a compound Datatype.
protected List<Long>	compoundMemberOffsets	The list of offsets of members of a compound Datatype.
protected List<Datatype>	compoundMemberTypes	The list of types of members of a compound Datatype.
protected int	datatypeClass	The class of the datatype.
protected String	datatypeDescription	The description of the datatype.
protected boolean	datatypeNATIVE	The description of the datatype.
protected int	datatypeOrder	The byte order of the datatype.
protected int	datatypeSign	The sign of the datatype.
protected long	datatypeSize	The size (in bytes) of the datatype.
protected Map<String,String>	enumMembers	The (name, value) pairs of enum members.
protected boolean	isNamed	Determines whether this datatype is a named datatype
protected boolean	isVariableStr	Determines whether this datatype is a variable-length string type.
protected boolean	isVLEN	Determines whether this datatype is a variable-length type.
static final int	NATIVE	The default definition for datatype size, order, and sign.
static final int	NSGN	See HDF5 Datatypes in HDF5 User Guide
static final int	ORDER_BE	See HDF5 Datatypes in HDF5 User Guide
static final int	ORDER_LE	See HDF5 Datatypes in HDF5 User Guide
static final int	ORDER_NONE	See HDF5 Datatypes in HDF5 User Guide
static final int	ORDER_VAX	See HDF5 Datatypes in HDF5 User Guide
static final int	SIGN_2	See HDF5 Datatypes in HDF5 User Guide
static final int	SIGN_NONE	See HDF5 Datatypes in HDF5 User Guide

Fields inherited from class hdf.object.HObject

fileFormat, linkTargetObjName, oid, SEPARATOR

Constructor Summary

Constructors

Constructor	Description
Datatype(int tclass, int tsize, int torder, int tsign)	Constructs a Datatype with specified class, size, byte order and sign.
Datatype(int tclass, int tsize, int torder, int tsign, Datatype tbase)	Constructs a Datatype with specified class, size, byte order and sign.
Datatype(int tclass, int tsize, int torder, int tsign, Datatype tbase, Datatype pbase)	Constructs a Datatype with specified class, size, byte order and sign.
Datatype(FileFormat theFile, int tclass, int tsize, int torder, int tsign, Datatype tbase, Datatype pbase)	Constructs a Datatype with specified class, size, byte order and sign.
Datatype(FileFormat theFile, long tid)	Constructs a Datatype with a given native datatype identifier.
Datatype(FileFormat theFile, long tid, Datatype pbase)	Constructs a Datatype with a given native datatype identifier.
Datatype(FileFormat theFile, String typeName, String typePath)	Constructs a named datatype with a given file, name and path.
Datatype(FileFormat theFile, String typeName, String typePath, long[] oid)	Deprecated. Not for public use in the future. Using Datatype(FileFormat, String, String)

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all of the elements from metadata list.
abstract void	close(long id)	Closes a datatype identifier.
abstract long	createNative()	Converts the datatype object to a native datatype.
abstract void	fromNative(long nativeID)	Set datatype characteristics (class, size, byte order and sign) from a given datatype identifier.
final long[]	getArrayDims()	Returns the dimensions of an Array Datatype.
final List<String>	getCompoundMemberNames()	Returns the member names of a Compound Datatype.
final List<Long>	getCompoundMemberOffsets()	Returns the member offsets of a Compound Datatype.
final List<Datatype>	getCompoundMemberTypes()	Returns member types of a Compound Datatype.
Datatype	getDatatypeBase()	Returns the base datatype for this datatype.
int	getDatatypeClass()	Returns the class of the datatype.
int	getDatatypeOrder()	Returns the byte order of the datatype.
int	getDatatypeSign()	Returns the sign (SIGN_NONE, SIGN_2) of an integer datatype.
long	getDatatypeSize()	Returns the size of the datatype in bytes.
String	getDescription()	Returns a short text description of this datatype.
final Map<String,String>	getEnumMembers()	Returns the Map<String,String> pairs of enum members for enum datatype.
final String	getEnumMembersAsString()	Returns the HashMap pairs of enum members for enum datatype.
List	getMetadata()	Retrieves the object's metadata, such as attributes, from the file.
long	getReferenceType()	If the datatype is a reference, then return the type.
boolean	isArray()	Checks if this datatype is an array type.
boolean	isBitField()	Checks if this datatype is a bitfield type.
boolean	isChar()	Checks if this datatype is a character type.
boolean	isCompound()	Checks if this datatype is an compound type.
boolean	isEnum()	Checks if this datatype is a enum type.
boolean	isFloat()	Checks if this datatype is a floating-point type.
boolean	isInteger()	Checks if this datatype is an integer type.
boolean	isNamed()	Checks if this datatype is a named type.
boolean	isOpaque()	Checks if this datatype is a opaque type.
boolean	isRef()	Checks if this datatype is a reference type.
boolean	isString()	Checks if this datatype is a string type.
abstract boolean	isText()	Checks if this datatype is a boolean type.
boolean	isUnsigned()	Checks if this datatype is unsigned.
boolean	isVarStr()	Checks if this datatype is a variable-length string type.
boolean	isVLEN()	Checks if this datatype is a variable-length type.
long	open()	Opens access to this named datatype.
void	removeMetadata(Object info)	Deletes an existing piece of metadata from this object.
final void	setEnumMembers(String enumStr)	Sets the (key, value) pairs of enum members for enum datatype.
String	toString()	Returns the name of the object.
void	updateMetadata(Object info)	Updates an existing piece of metadata attached to this object.
void	writeMetadata(Object info)	Writes a specific piece of metadata (such as an attribute) into the file.

Methods inherited from class hdf.object.HObject

createFullname, debug, equals, equals, equalsOID, getFID, getFile, getFileFormat, getFullName, getLinkTargetObjName, getName, getOID, getPath, hashCode, setFullname, setLinkTargetObjName, setName, setPath

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface hdf.object.MetaDataContainer

hasAttribute

Field Details

NATIVE

public static final int NATIVE

The default definition for datatype size, order, and sign.

See Also:

• Constant Field Values

CLASS_NO_CLASS

public static final int CLASS_NO_CLASS

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_INTEGER

public static final int CLASS_INTEGER

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_FLOAT

public static final int CLASS_FLOAT

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_CHAR

public static final int CLASS_CHAR

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_STRING

public static final int CLASS_STRING

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_BITFIELD

public static final int CLASS_BITFIELD

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_OPAQUE

public static final int CLASS_OPAQUE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_COMPOUND

public static final int CLASS_COMPOUND

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_REFERENCE

public static final int CLASS_REFERENCE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_ENUM

public static final int CLASS_ENUM

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_VLEN

public static final int CLASS_VLEN

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_ARRAY

public static final int CLASS_ARRAY

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

CLASS_TIME

public static final int CLASS_TIME

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

ORDER_LE

public static final int ORDER_LE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

ORDER_BE

public static final int ORDER_BE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

ORDER_VAX

public static final int ORDER_VAX

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

ORDER_NONE

public static final int ORDER_NONE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

SIGN_NONE

public static final int SIGN_NONE

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

SIGN_2

public static final int SIGN_2

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

NSGN

public static final int NSGN

See HDF5 Datatypes in HDF5 User Guide

See Also:

• Constant Field Values

datatypeDescription

protected String datatypeDescription

The description of the datatype.

datatypeNATIVE

protected boolean datatypeNATIVE

The description of the datatype.

datatypeClass

protected int datatypeClass

The class of the datatype.

datatypeSize

protected long datatypeSize

The size (in bytes) of the datatype.

datatypeOrder

protected int datatypeOrder

The byte order of the datatype. Valid values are ORDER_LE, ORDER_BE, and ORDER_VAX.

datatypeSign

protected int datatypeSign

The sign of the datatype.

baseType

protected Datatype baseType

The base datatype of this datatype (null if this datatype is atomic).

isNamed

protected boolean isNamed

Determines whether this datatype is a named datatype

arrayDims

protected long[] arrayDims

The dimensions of the ARRAY element of an ARRAY datatype.

isVLEN

protected boolean isVLEN

Determines whether this datatype is a variable-length type.

isVariableStr

protected boolean isVariableStr

Determines whether this datatype is a variable-length string type.

enumMembers

protected Map<String,String> enumMembers

The (name, value) pairs of enum members.

compoundMemberNames

protected List<String> compoundMemberNames

The list of names of members of a compound Datatype.

compoundMemberTypes

protected List<Datatype> compoundMemberTypes

The list of types of members of a compound Datatype.

compoundMemberOffsets

protected List<Long> compoundMemberOffsets

The list of offsets of members of a compound Datatype.

Constructor Details

Datatype

public Datatype(FileFormat theFile,
 String typeName,
 String typePath)

Constructs a named datatype with a given file, name and path.

Parameters:

theFile - the HDF file.

typeName - the name of the datatype, e.g "12-bit Integer".

typePath - the full group path of the datatype, e.g. "/datatypes/".

Datatype

@Deprecated
public Datatype(FileFormat theFile,
 String typeName,
 String typePath,
 long[] oid)

Deprecated.

Not for public use in the future.
Using Datatype(FileFormat, String, String)

Parameters:

theFile - the HDF file.

typeName - the name of the datatype, e.g "12-bit Integer".

typePath - the full group path of the datatype, e.g. "/datatypes/".

oid - the oidof the datatype.

Datatype

public Datatype(int tclass,
 int tsize,
 int torder,
 int tsign)
         throws Exception

Constructs a Datatype with specified class, size, byte order and sign. The following is a list of a few examples of Datatype.

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

Parameters:

tclass - the class of the datatype, e.g. CLASS_INTEGER, CLASS_FLOAT and etc.

tsize - the size of the datatype in bytes, e.g. for a 32-bit integer, the size is 4. Valid values are NATIVE or a positive value.

torder - the byte order of the datatype. Valid values are ORDER_LE, ORDER_BE, ORDER_VAX, ORDER_NONE and NATIVE.

tsign - the sign of the datatype. Valid values are SIGN_NONE, SIGN_2 and NATIVE.

Throws:

Exception - if there is an error

Datatype

public Datatype(int tclass,
 int tsize,
 int torder,
 int tsign,
 Datatype tbase)
         throws Exception

Constructs a Datatype with specified class, size, byte order and sign. The following is a list of a few examples of Datatype.

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

Parameters:

tclass - the class of the datatype, e.g. CLASS_INTEGER, CLASS_FLOAT and etc.

tsize - the size of the datatype in bytes, e.g. for a 32-bit integer, the size is 4. Valid values are NATIVE or a positive value.

torder - the byte order of the datatype. Valid values are ORDER_LE, ORDER_BE, ORDER_VAX, ORDER_NONE and NATIVE.

tsign - the sign of the datatype. Valid values are SIGN_NONE, SIGN_2 and NATIVE.

tbase - the base datatype of the new datatype

Throws:

Exception - if there is an error

Datatype

public Datatype(FileFormat theFile,
 int tclass,
 int tsize,
 int torder,
 int tsign,
 Datatype tbase,
 Datatype pbase)
         throws Exception

Constructs a Datatype with specified class, size, byte order and sign. The following is a list of a few examples of Datatype.

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

Parameters:

theFile - the HDF file.

tclass - the class of the datatype, e.g. CLASS_INTEGER, CLASS_FLOAT and etc.

tsize - the size of the datatype in bytes, e.g. for a 32-bit integer, the size is 4. Valid values are NATIVE or a positive value.

torder - the byte order of the datatype. Valid values are ORDER_LE, ORDER_BE, ORDER_VAX, ORDER_NONE and NATIVE.

tsign - the sign of the datatype. Valid values are SIGN_NONE, SIGN_2 and NATIVE.

tbase - the base datatype of the new datatype

pbase - the parent datatype of the new datatype

Throws:

Exception - if there is an error

Datatype

public Datatype(int tclass,
 int tsize,
 int torder,
 int tsign,
 Datatype tbase,
 Datatype pbase)
         throws Exception

Constructs a Datatype with specified class, size, byte order and sign. The following is a list of a few examples of Datatype.

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

Parameters:

tclass - the class of the datatype, e.g. CLASS_INTEGER, CLASS_FLOAT and etc.

tsize - the size of the datatype in bytes, e.g. for a 32-bit integer, the size is 4. Valid values are NATIVE or a positive value.

torder - the byte order of the datatype. Valid values are ORDER_LE, ORDER_BE, ORDER_VAX, ORDER_NONE and NATIVE.

tsign - the sign of the datatype. Valid values are SIGN_NONE, SIGN_2 and NATIVE.

tbase - the base datatype of the new datatype

pbase - the parent datatype of the new datatype

Throws:

Exception - if there is an error

Datatype

public Datatype(FileFormat theFile,
 long tid)
         throws Exception

Constructs a Datatype with a given native datatype identifier. For example, if the datatype identifier is a 32-bit unsigned integer created from HDF5,

 long tid = H5.H5Tcopy(HDF5Constants.H5T_NATIVE_UNINT32);
 Datatype dtype = new Datatype(tid);
 

will construct a datatype equivalent to new Datatype(CLASS_INTEGER, 4, NATIVE, SIGN_NONE);

Parameters:

theFile - the HDF file.

tid - the native datatype identifier.

Throws:

Exception - if there is an error

See Also:

• fromNative(long tid)

Datatype

public Datatype(FileFormat theFile,
 long tid,
 Datatype pbase)
         throws Exception

Constructs a Datatype with a given native datatype identifier. For example, if the datatype identifier is a 32-bit unsigned integer created from HDF5,

 long tid = H5.H5Tcopy(HDF5Constants.H5T_NATIVE_UNINT32);
 Datatype dtype = new Datatype(tid);
 

will construct a datatype equivalent to new Datatype(CLASS_INTEGER, 4, NATIVE, SIGN_NONE);

Parameters:

theFile - the HDF file.

tid - the native datatype identifier.

pbase - the parent datatype of the new datatype

Throws:

Exception - if there is an error

See Also:

• fromNative(long tid)

Method Details

open

public long open()

Opens access to this named datatype. Sub-classes must replace this default implementation. For example, in H5Datatype, open() function H5.H5Topen(loc_id, name) to get the datatype identifier.

Specified by:

open in class HObject

Returns:

the datatype identifier if successful; otherwise returns negative value.

See Also:

• HObject.close(long)

close

public abstract void close(long id)

Closes a datatype identifier. Sub-classes must replace this default implementation.

Specified by:

close in class HObject

Parameters:

id - the datatype identifier to close.

getDatatypeClass

public int getDatatypeClass()

Returns the class of the datatype. Valid values are:

• CLASS_NO_CLASS
• CLASS_INTEGER
• CLASS_FLOAT
• CLASS_CHAR
• CLASS_STRING
• CLASS_BITFIELD
• CLASS_OPAQUE
• CLASS_COMPOUND
• CLASS_REFERENCE
• CLASS_ENUM
• CLASS_VLEN
• CLASS_ARRAY

Returns:

the class of the datatype.

getDatatypeSize

public long getDatatypeSize()

Returns the size of the datatype in bytes. For example, for a 32-bit integer, the size is 4 (bytes).

Returns:

the size of the datatype.

getDatatypeOrder

public int getDatatypeOrder()

Returns the byte order of the datatype. Valid values are

• ORDER_LE
• ORDER_BE
• ORDER_VAX
• ORDER_NONE

Returns:

the byte order of the datatype.

getDatatypeSign

public int getDatatypeSign()

Returns the sign (SIGN_NONE, SIGN_2) of an integer datatype.

Returns:

the sign of the datatype.

getDatatypeBase

public Datatype getDatatypeBase()

Returns the base datatype for this datatype. For example, in a dataset of type ARRAY of integer, the datatype of the dataset is ARRAY. The datatype of the base type is integer.

Returns:

the datatype of the contained basetype.

setEnumMembers

public final void setEnumMembers(String enumStr)

Sets the (key, value) pairs of enum members for enum datatype. For Example,

setEnumMembers("-40=lowTemp, 90=highTemp")

sets the key of enum member lowTemp to -40 and highTemp to 90.

setEnumMembers("lowTemp, highTemp")

sets enum members to defaults, i.e. 0=lowTemp and 1=highTemp

setEnumMembers("10=lowTemp, highTemp")

sets enum member lowTemp to 10 and highTemp to 11.

Parameters:

enumStr - the (key, value) pairs of enum members

getEnumMembers

public final Map<String,String> getEnumMembers()

Returns the Map<String,String> pairs of enum members for enum datatype.

Returns:

enumStr Map<String,String%gt; pairs of enum members

getEnumMembersAsString

public final String getEnumMembersAsString()

Returns the HashMap pairs of enum members for enum datatype. For Example,

getEnumMembersAsString()

returns "10=lowTemp, 40=highTemp"

Returns:

enumStr the (key, value) pairs of enum members

getArrayDims

public final long[] getArrayDims()

Returns the dimensions of an Array Datatype.

Returns:

dims the dimensions of the Array Datatype

getCompoundMemberNames

public final List<String> getCompoundMemberNames()

Returns the member names of a Compound Datatype.

Returns:

member names of a Compound Datatype

getCompoundMemberTypes

public final List<Datatype> getCompoundMemberTypes()

Returns member types of a Compound Datatype.

Returns:

member types of a Compound Datatype

getCompoundMemberOffsets

public final List<Long> getCompoundMemberOffsets()

Returns the member offsets of a Compound Datatype.

Returns:

member offsets of a Compound Datatype

createNative

public abstract long createNative()

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.createNative();
 

The "tid" will be the HDF5 datatype id of a 64-bit unsigned integer, which is equivalent to

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

Returns:

the identifier of the native datatype.

fromNative

public abstract void fromNative(long nativeID)

Set datatype characteristics (class, size, byte order and sign) from a given datatype identifier. Sub-classes must implement it so that this datatype will be converted accordingly. For example, if the type identifier is a 64-bit unsigned integer created from HDF5,

 H5Datatype dtype = new H5Datatype();
 dtype.fromNative(HDF5Constants.H5T_NATIVE_UNINT32);
 

Where dtype is equivalent to
new H5Datatype(CLASS_INTEGER, 4, NATIVE, SIGN_NONE);

Parameters:

nativeID - the datatype identifier.

getReferenceType

public long getReferenceType()

If the datatype is a reference, then return the type.

Returns:

the datatype reference type if successful; otherwise returns negative value.

getDescription

public String getDescription()

Returns a short text description of this datatype.

Returns:

a short text description of this datatype

isUnsigned

public boolean isUnsigned()

Checks if this datatype is unsigned.

Returns:

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

isText

public abstract boolean isText()

Checks if this datatype is a boolean type.

Returns:

true if the datatype is boolean; false otherwise

isInteger

public boolean isInteger()

Checks if this datatype is an integer type.

Returns:

true if the datatype is integer; false otherwise

isFloat

public boolean isFloat()

Checks if this datatype is a floating-point type.

Returns:

true if the datatype is floating-point; false otherwise

isNamed

public boolean isNamed()

Checks if this datatype is a named type.

Returns:

true if the datatype is named; false otherwise

isVarStr

public boolean isVarStr()

Checks if this datatype is a variable-length string type.

Returns:

true if the datatype is variable-length string; false otherwise

isVLEN

public boolean isVLEN()

Checks if this datatype is a variable-length type.

Returns:

true if the datatype is variable-length; false otherwise

isCompound

public boolean isCompound()

Checks if this datatype is an compound type.

Returns:

true if the datatype is compound; false otherwise

isArray

public boolean isArray()

Checks if this datatype is an array type.

Returns:

true if the datatype is array; false otherwise

isString

public boolean isString()

Checks if this datatype is a string type.

Returns:

true if the datatype is string; false otherwise

isChar

public boolean isChar()

Checks if this datatype is a character type.

Returns:

true if the datatype is character; false otherwise

isRef

public boolean isRef()

Checks if this datatype is a reference type.

Returns:

true if the datatype is reference; false otherwise

isEnum

public boolean isEnum()

Checks if this datatype is a enum type.

Returns:

true if the datatype is enum; false otherwise

isOpaque

public boolean isOpaque()

Checks if this datatype is a opaque type.

Returns:

true if the datatype is opaque; false otherwise

isBitField

public boolean isBitField()

Checks if this datatype is a bitfield type.

Returns:

true if the datatype is bitfield; false otherwise

clear

public void clear()

Removes all of the elements from metadata list. The list should be empty after this call returns.

Specified by:

clear in interface MetaDataContainer

getMetadata

public List getMetadata()
                 throws Exception

Retrieves the object's metadata, such as attributes, from the file. Metadata, such as attributes, is stored in a List.

Specified by:

getMetadata in interface MetaDataContainer

Returns:

the list of metadata objects.

Throws:

Exception - if the metadata can not be retrieved

writeMetadata

public void writeMetadata(Object info)
                   throws Exception

Writes a specific piece of metadata (such as an attribute) into the file. If an HDF(4&5) attribute exists in the file, this method updates its value. If the attribute does not exist in the file, it creates the attribute in the file and attaches it to the object. It will fail to write a new attribute to the object where an attribute with the same name already exists. To update the value of an existing attribute in the file, one needs to get the instance of the attribute by getMetadata(), change its values, then use writeMetadata() to write the value.

Specified by:

writeMetadata in interface MetaDataContainer

Parameters:

info - the metadata to write.

Throws:

Exception - if the metadata can not be written

removeMetadata

public void removeMetadata(Object info)
                    throws Exception

Deletes an existing piece of metadata from this object.

Specified by:

removeMetadata in interface MetaDataContainer

Parameters:

info - the metadata to delete.

Throws:

Exception - if the metadata can not be removed

updateMetadata

public void updateMetadata(Object info)
                    throws Exception

Updates an existing piece of metadata attached to this object.

Specified by:

updateMetadata in interface MetaDataContainer

Parameters:

info - the metadata to update.

Throws:

Exception - if the metadata can not be updated

toString

public String toString()

Description copied from class: HObject

Returns the name of the object. This method overwrites the toString() method in the Java Object class (the root class of all Java objects) so that it returns the name of the HObject instead of the name of the class. For example, toString() returns "Raster Image #2" instead of "hdf.object.h4.H4SDS".

Overrides:

toString in class HObject

Returns:

The name of the object.