DataObject

Java Interface

/

• A general interface for data objects. A data object consists of an identifier,
• binary content and metadata. */

public interface DataObject {

/

• Gets the data object's primary identifier.
• @return An identifier for this data object. */

public URI getID();

/

• Returns the byte size of the represented resource. This has been defined at
• this global level due to the importance of this attribute for performance reasons.
• @return the size of the binary resource in bytes, or a negative value when the
• size is unknown or does not make sense for this particular DataObject implementation. */

public long getSize();

/

• Gets the DataSource from which this DataObject conceptually originated.
• @return The DataSource from which this DataObject conceptually originated. */

public DataSource getDataSource();

/

• Gets the data object's parent, if any.
• @return the parent DataObject, or null when this DataObject has no parent. */

public DataObject getParent();

/

• Gets the data object's children, if any. This may be null to indicate that there
• are no children. */

public Iterator<DataObject> getChildren();

/

• Gets an InputStream containing the content represented by the DataObject.
• The returned InputStream is required to support marking (markSupported()
• returns true). Calling this method multiple times may references to
• one-and-the-same InputStream instance. Care should therefore be taken to mark
• and reset the stream when the stream's content is to be read again later.
• @return An InputStream from which the content of the data object can be read.
• @throws IOException If an I/O error occurred. */

public InputStream getContent() throws IOException;

/

• Instructs the DataObject that its content stream will most likely be used multiple
• times in its entirety, making the mark-and-reset procedure difficult to work,
• and that it better should cache the entire contents.
• @throws IOException when an IOException occured during caching of the content. */

´ public void cacheContent() throws IOException;

/

• Get the source-specific metadata.
• The used keys and values and implementation-dependent.
• @return The scheme-specific metadata. */

public Map<Object, Object> getMetaData();

}