Module org.hdfgroup.object

Package hdf.object

Interface Attribute

All Known Subinterfaces:

H5Attribute

All Known Implementing Classes:

FitsAttribute, H4CompoundAttribute, H4ScalarAttribute, H5CompoundAttr, H5ScalarAttr, NC2Attribute

public interface Attribute

An interface that provides general attribute operations for object data. For example, reference to a parent object.

See Also:

• HObject

Method Summary

Modifier and Type	Method	Description
Object	getAttributeData()	Retrieves the attribute data from the file.
Datatype	getAttributeDatatype()	Returns the datatype of the attribute.
long[]	getAttributeDims()	Returns the array that contains the dimension sizes of the data value of the attribute.
String	getAttributeName()	Returns the name of the attribute.
int	getAttributePlane()	Returns the selected size of the rows and columns of the attribute.
int	getAttributeRank()	Returns the rank (number of dimensions) of the attribute.
int	getAttributeSpaceType()	Returns the space type for the attribute.
HObject	getParentObject()	Returns the HObject to which this Attribute is currently "attached".
Object	getProperty(String key)	get a property for a given key.
Collection<String>	getPropertyKeys()	get all property keys.
boolean	isAttributeNULL()	Check if attribute's dataspace is a NULL
boolean	isAttributeScalar()	Check if attribute is a single scalar point
void	setAttributeData(Object d)	Not for public use in the future.
void	setParentObject(HObject pObj)	Sets the HObject to which this Attribute is "attached".
void	setProperty(String key, Object value)	set a property for the attribute.
String	toAttributeString(String delimiter)	Returns a string representation of the data value.
String	toAttributeString(String delimiter, int maxItems)	Returns a string representation of the data value.
void	writeAttribute()	Writes the memory buffer of this dataset to file.
void	writeAttribute(Object buf)	Writes the given data buffer into this attribute in a file.

Method Details

getParentObject

HObject getParentObject()

Returns the HObject to which this Attribute is currently "attached".

Returns:

the HObject to which this Attribute is currently "attached".

setParentObject

void setParentObject(HObject pObj)

Sets the HObject to which this Attribute is "attached".

Parameters:

pObj - the new HObject to which this Attributet is "attached".

setProperty

void setProperty(String key,
 Object value)

set a property for the attribute.

Parameters:

key - the attribute Map key

value - the attribute Map value

getProperty

Object getProperty(String key)

get a property for a given key.

Parameters:

key - the attribute Map key

Returns:

the property

getPropertyKeys

Collection<String> getPropertyKeys()

get all property keys.

Returns:

the Collection of property keys

getAttributeName

String getAttributeName()

Returns the name of the attribute.

Returns:

The name of the attribute.

getAttributeData

Object getAttributeData()
                 throws Exception,
OutOfMemoryError

Retrieves the attribute data from the file.

Returns:

the attribute data.

Throws:

Exception - if the data can not be retrieved

OutOfMemoryError

getAttributeDatatype

Datatype getAttributeDatatype()

Returns the datatype of the attribute.

Returns:

the datatype of the attribute.

getAttributeSpaceType

int getAttributeSpaceType()

Returns the space type for the attribute. It returns a negative number if it failed to retrieve the type information from the file.

Returns:

the space type for the attribute.

getAttributeRank

int getAttributeRank()

Returns the rank (number of dimensions) of the attribute. It returns a negative number if it failed to retrieve the dimension information from the file.

Returns:

the number of dimensions of the attribute.

getAttributeDims

long[] getAttributeDims()

Returns the array that contains the dimension sizes of the data value of the attribute. It returns null if it failed to retrieve the dimension information from the file.

Returns:

the dimension sizes of the attribute.

getAttributePlane

int getAttributePlane()

Returns the selected size of the rows and columns of the attribute. It returns a negative number if it failed to retrieve the size information from the file.

Returns:

the selected size of the rows and colums of the attribute.

isAttributeNULL

boolean isAttributeNULL()

Check if attribute's dataspace is a NULL

Returns:

true if the dataspace is a NULL; otherwise, returns false.

isAttributeScalar

boolean isAttributeScalar()

Check if attribute is a single scalar point

Returns:

true if the data is a single scalar point; otherwise, returns false.

setAttributeData

void setAttributeData(Object d)

Not for public use in the future. setAttributeData() is not safe to use because it changes memory buffer of the dataset object. Dataset operations such as write/read will fail if the buffer type or size is changed.

Parameters:

d - the object data -must be an array of Objects

writeAttribute

void writeAttribute()
             throws Exception

Writes the memory buffer of this dataset to file.

Throws:

Exception - if buffer can not be written

writeAttribute

void writeAttribute(Object buf)
             throws Exception

Writes the given data buffer into this attribute in a file. The data buffer is a vector that contains the data values of compound fields. The data is written into file as one data blob.

Parameters:

buf - The vector that contains the data values of compound fields.

Throws:

Exception - If there is an error at the library level.

toAttributeString

String toAttributeString(String delimiter)

Returns a string representation of the data value. For example, "0, 255". For a compound datatype, it will be a 1D array of strings with field members separated by the delimiter. For example, "{0, 10.5}, {255, 20.0}, {512, 30.0}" is a compound attribute of {int, float} of three data points.

Parameters:

delimiter - The delimiter used to separate individual data points. It can be a comma, semicolon, tab or space. For example, toString(",") will separate data by commas.

Returns:

the string representation of the data values.

toAttributeString

String toAttributeString(String delimiter,
 int maxItems)

Returns a string representation of the data value. For example, "0, 255". For a compound datatype, it will be a 1D array of strings with field members separated by the delimiter. For example, "{0, 10.5}, {255, 20.0}, {512, 30.0}" is a compound attribute of {int, float} of three data points.

Parameters:

delimiter - The delimiter used to separate individual data points. It can be a comma, semicolon, tab or space. For example, toString(",") will separate data by commas.

maxItems - The maximum number of Array values to return

Returns:

the string representation of the data values.