Module org.hdfgroup.object

Package hdf.object

Interface MetaDataContainer

All Known Implementing Classes:

Datatype, FitsDataset, FitsDatatype, FitsGroup, Group, H4Datatype, H4GRImage, H4Group, H4SDS, H4Vdata, H5CompoundDS, H5Datatype, H5Group, H5Link, H5MetaDataContainer, H5ReferenceType, H5ScalarDS, NC2Dataset, NC2Datatype, NC2Group

public interface MetaDataContainer

An interface that provides general I/O operations for object metadata attached to an object. For example, reading metadata content from the file into memory or writing metadata content from memory into the file.

Version:

2.0 4/2/2018

Author:

Peter X. Cao, Jordan T. Henderson

See Also:

• HObject

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all of the elements from metadata list.
List	getMetadata()	Retrieves the object's metadata, such as attributes, from the file.
boolean	hasAttribute()	Check if the object has any attributes attached.
void	removeMetadata(Object metadata)	Deletes an existing piece of metadata from this object.
void	updateMetadata(Object metadata)	Updates an existing piece of metadata attached to this object.
void	writeMetadata(Object metadata)	Writes a specific piece of metadata (such as an attribute) into the file.

Method Details

getMetadata

List getMetadata()
          throws Exception

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

Returns:

the list of metadata objects.

Throws:

Exception - if the metadata can not be retrieved

writeMetadata

void writeMetadata(Object metadata)
            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.

Parameters:

metadata - the metadata to write.

Throws:

Exception - if the metadata can not be written

removeMetadata

void removeMetadata(Object metadata)
             throws Exception

Deletes an existing piece of metadata from this object.

Parameters:

metadata - the metadata to delete.

Throws:

Exception - if the metadata can not be removed

updateMetadata

void updateMetadata(Object metadata)
             throws Exception

Updates an existing piece of metadata attached to this object.

Parameters:

metadata - the metadata to update.

Throws:

Exception - if the metadata can not be updated

hasAttribute

boolean hasAttribute()

Check if the object has any attributes attached.

Returns:

true if it has any attributes, false otherwise.

clear

void clear()

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