Package ncsa.hdf.object
Interface DataFormat
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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
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description 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
updateMetadata(java.lang.Object info)
Updates an existing metadata from this data object.void
writeMetadata(java.lang.Object info)
Writes a specific metadata (such as attribute) into file.
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Method Detail
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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.
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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
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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
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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
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updateMetadata
void updateMetadata(java.lang.Object info) throws java.lang.Exception
Updates an existing metadata from this data object.- Parameters:
info
- the metadata to update.- Throws:
java.lang.Exception
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hasAttribute
boolean hasAttribute()
Check if the object has any attributes attached.- Returns:
- true if it has any attribute(s), false otherwise.
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