Changes between Initial Version and Version 1 of ApertureDataObject

Timestamp:

10/12/05 14:27:28 (20 years ago)

Author:

dburkhar

Comment:

--

ApertureDataObject

@@ +1 @@
+= 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();
+}