Package ncsa.hdf.object

Interface DataFormat

  • All Known Implementing Classes:
    CompoundDS, Dataset, Datatype, Group, HObject, 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

      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.

    • 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

      • 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

      • hasAttribute

        boolean hasAttribute()
        Check if the object has any attributes attached.
        Returns:
        true if it has any attribute(s), false otherwise.