ncsa.hdf.object
Interface DataFormat

All Known Implementing Classes:

CompoundDS, Dataset, Datatype, FitsDataset, FitsDatatype, FitsGroup, Group, H4Datatype, H4GRImage, H4Group, H4SDS, H4Vdata, H5CompoundDS, H5Datatype, H5Group, H5Link, H5ScalarDS, HObject, NC2Dataset, NC2Datatype, NC2Group, ScalarDS

public interface DataFormat

An interface that provides general I/O operations for read/write object data. For example, reading data content or data attribute from file into memory or writing data content or data attribute from memory into file.

Version:

1.1 9/4/2007

Author:

Peter X. Cao

See Also:

HObject

Method Summary

java.lang.String	getFile() Returns the full path of the file that contains this data object.
java.util.List	getMetadata() Retrieves the metadata such as attributes from file.
boolean	hasAttribute() Check if the object has any attributes attached.
void	removeMetadata(java.lang.Object info) Deletes an existing metadata from this data object.
void	writeMetadata(java.lang.Object info) Writes a specific metadata (such as attribute) into file.

Method Detail

getFile

java.lang.String getFile()

Returns the full path of the file that contains this data object.

The file name is necessary because data objects are uniquely identified by object reference and file name when mutilple files are opened at the same time.

getMetadata

java.util.List getMetadata()
                           throws java.lang.Exception

Retrieves the metadata such as attributes from file.

Metadata such as attributes are stored in a List.

Returns:

the list of metadata objects.

Throws:

java.lang.Exception

writeMetadata

void writeMetadata(java.lang.Object info)
                   throws java.lang.Exception

Writes a specific metadata (such as attribute) into file.

If an HDF(4&5) attribute exists in file, the method updates its value. If the attribute does not exists in file, it creates the attribute in 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 file, one needs to get the instance of the attribute by getMetadata(), change its values, and use writeMetadata() to write the value.

Parameters:

info - the metadata to write.

Throws:

java.lang.Exception

removeMetadata

void removeMetadata(java.lang.Object info)
                    throws java.lang.Exception

Deletes an existing metadata from this data object.

Parameters:

info - the metadata to delete.

Throws:

java.lang.Exception

hasAttribute

boolean hasAttribute()

Check if the object has any attributes attached.

Returns:

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