BitmapWalkListener: Use plain interface with noop instance

In this new interface default methods are useful only to instantiate
noop instances. We rather reuse the same noop instance and save the
"default" to add backward compatible methods to existing interfaces.

Make the methods regular interface methods and provide a noop
instance.

Change-Id: Ie84ff17c8e9f16837245751739ee8c99463e76ee

1 files changed, 28 insertions, 14 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
index 2218462426..c0e41d644a 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
@@ -54,14 +54,13 @@ public final class BitmapWalker {
 	 */
 	public interface BitmapWalkListener {
 		/**
-		 * The commit is already in the walk bitmap
+		 * The commit was already visited or is reachable from a visited commit
 		 *
 		 * @param oid
-		 *            objectId of the commit already in bitmap
+		 *            objectId of the commit already visited directly or
+		 *            indirectly
 		 */
-		default void onCommitInBitmap(ObjectId oid) {
-			// Nothing to do
-		}
+		void onCommitSeen(ObjectId oid);
 
 		/**
 		 * The commit has a bitmap in the bitmap index
@@ -69,9 +68,7 @@ public final class BitmapWalker {
 		 * @param oid
 		 *            objectId of the commit with a bitmap in the bitmap index
 		 */
-		default void onCommitWithBitmap(ObjectId oid) {
-			// Nothing to do
-		}
+		void onCommitWithBitmap(ObjectId oid);
 
 		/**
 		 * The commit doesn't have bitmap
@@ -80,13 +77,30 @@ public final class BitmapWalker {
 		 *            objectId of the commit without a bitmap in the bitmap
 		 *            index
 		 */
-		default void onCommitWithoutBitmap(ObjectId oid) {
+		void onCommitWithoutBitmap(ObjectId oid);
+
+	}
+
+	/**
+	 * Empty listener
+	 *
+	 * @since 6.8
+	 */
+	public static final BitmapWalkListener NOOP_LISTENER = new BitmapWalkListener() {
+		@Override
+		public void onCommitSeen(ObjectId oid) {
+			// Nothing to do
+		}
+
+		@Override
+		public void onCommitWithBitmap(ObjectId oid) {
 			// Nothing to do
 		}
-	}
 
-	private static final BitmapWalkListener NO_LISTENER = new BitmapWalkListener() {
-		// Default methods
+		@Override
+		public void onCommitWithoutBitmap(ObjectId oid) {
+			// Nothing to do
+		}
 	};
 
 	private final BitmapWalkListener listener;
@@ -100,7 +114,7 @@ public final class BitmapWalker {
 	 */
 	public BitmapWalker(
 			ObjectWalk walker, BitmapIndex bitmapIndex, ProgressMonitor pm) {
-		this(walker, bitmapIndex, pm, NO_LISTENER);
+		this(walker, bitmapIndex, pm, NOOP_LISTENER);
 	}
 
 	/**
@@ -114,7 +128,7 @@ public final class BitmapWalker {
 	 *            progress monitor to report progress on.
 	 * @param listener
 	 *            listener of event happening during the walk. Use
-	 *            {@link #NO_LISTENER} for a no-op listener.
+	 *            {@link BitmapWalker#NOOP_LISTENER} for a no-op listener.
 	 *
 	 * @since 6.8
 	 */