Delegate repository access to refs, objects

Instead of using the internal field directly to access references
or objects, use the getter method to obtain the proper type of
database, and follow down from there.  This permits us to later
do a refactoring that makes those methods abstract and strips the
field out of the Repository class, moving it into a concrete base
class that is more storage implementation specific.

Change-Id: Ic21dd48800e68a04ce372965ad233485b2a84bef
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

 	 * @return true if the specified object is stored in this repo or any of the
 	 *         known shared repositories.
 	 */
-	public boolean hasObject(final AnyObjectId objectId) {
-		return objectDatabase.hasObject(objectId);
+	public boolean hasObject(AnyObjectId objectId) {
+		return getObjectDatabase().hasObject(objectId);
 	}
 
 	/**
 	 *         object, or null if the object does not exist.
 	 * @throws IOException
 	 */
-	public ObjectLoader openObject(final WindowCursor curs, final AnyObjectId id)
+	public ObjectLoader openObject(WindowCursor curs, AnyObjectId id)
 			throws IOException {
-		return objectDatabase.openObject(curs, id);
+		return getObjectDatabase().openObject(curs, id);
 	}
 
 	/**
 	 *             to the base ref, as the symbolic ref could not be read.
 	 */
 	public RefUpdate updateRef(final String ref, final boolean detach) throws IOException {
-		return refs.newUpdate(ref, detach);
+		return getRefDatabase().newUpdate(ref, detach);
 	}
 
 	/**
 	 *
 	 */
 	public RefRename renameRef(final String fromRef, final String toRef) throws IOException {
-		return refs.newRename(fromRef, toRef);
+		return getRefDatabase().newRename(fromRef, toRef);
 	}
 
 	/**
 		useCnt.incrementAndGet();
 	}
 
-	/**
-	 * Close all resources used by this repository
-	 */
+	/** Decrement the use count, and maybe close resources. */
 	public void close() {
 		if (useCnt.decrementAndGet() == 0) {
-			objectDatabase.close();
-			refs.close();
+			doClose();
 		}
 	}
 
+	/**
+	 * Invoked when the use count drops to zero during {@link #close()}.
+	 * <p>
+	 * The default implementation closes the object and ref databases.
+	 */
+	protected void doClose() {
+		getObjectDatabase().close();
+		getRefDatabase().close();
+	}
+
 	/**
 	 * Add a single existing pack to the list of available pack files.
 	 *
 	 * @throws IOException
 	 */
 	public Ref getRef(final String name) throws IOException {
-		return refs.getRef(name);
+		return getRefDatabase().getRef(name);
 	}
 
 	/**
 	 */
 	public Map<String, Ref> getAllRefs() {
 		try {
-			return refs.getRefs(RefDatabase.ALL);
+			return getRefDatabase().getRefs(RefDatabase.ALL);
 		} catch (IOException e) {
 			return new HashMap<String, Ref>();
 		}
 	 */
 	public Map<String, Ref> getTags() {
 		try {
-			return refs.getRefs(Constants.R_TAGS);
+			return getRefDatabase().getRefs(Constants.R_TAGS);
 		} catch (IOException e) {
 			return new HashMap<String, Ref>();
 		}
 	 */
 	public Ref peel(final Ref ref) {
 		try {
-			return refs.peel(ref);
+			return getRefDatabase().peel(ref);
 		} catch (IOException e) {
 			// Historical accident; if the reference cannot be peeled due
 			// to some sort of repository access problem we claim that the