BUG-5280: move AbstractDataTreeModificationCursor

AbstractDataTreeModificationCursor functionality is useful for wide
range of users, move it to sal-clustering-commons.

Also eliminate the explicit stack, because YangInstanceIdentifier
already has O(1) methods to maintain a logical stack.

Change-Id: Ia0f8d24f32afd67c059e72cc967949f4c609fd7c
Signed-off-by: Robert Varga <rovarga@cisco.com>

diff --git a/java/org/opendaylight/controller/cluster/datastore/util/AbstractDataTreeModificationCursor.java b/java/org/opendaylight/controller/cluster/datastore/util/AbstractDataTreeModificationCursor.java
new file mode 100644 (file)
index 0000000..f83f6af
--- /dev/null
+++ b/java/org/opendaylight/controller/cluster/datastore/util/AbstractDataTreeModificationCursor.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2016 Brocade Communications Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.datastore.util;
+
+import com.google.common.annotations.Beta;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
+import javax.annotation.Nonnull;
+import javax.annotation.concurrent.NotThreadSafe;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModificationCursor;
+
+/**
+ * Abstract {@link DataTreeModificationCursor} which tracks the current path. Subclasses can get the current path
+ * via {@link #current()}.
+ *
+ * @author Thomas Pantelis
+ */
+@Beta
+@NotThreadSafe
+public abstract class AbstractDataTreeModificationCursor implements DataTreeModificationCursor {
+    private YangInstanceIdentifier current = YangInstanceIdentifier.EMPTY;
+
+    protected final YangInstanceIdentifier current() {
+        return current;
+    }
+
+    @Override
+    public final void enter(@Nonnull final PathArgument child) {
+        current = current.node(child);
+    }
+
+    @Override
+    public final void enter(@Nonnull final PathArgument... path) {
+        for (PathArgument arg : path) {
+            enter(arg);
+        }
+    }
+
+    @Override
+    public final void enter(@Nonnull final Iterable<PathArgument> path) {
+        for (PathArgument arg : path) {
+            enter(arg);
+        }
+    }
+
+    @Override
+    public final void exit() {
+        Preconditions.checkState(!current.isEmpty());
+        current = Verify.verifyNotNull(current.getParent());
+    }
+
+    @Override
+    public final void exit(final int depth) {
+        Preconditions.checkArgument(depth >= 0);
+
+        YangInstanceIdentifier next = current;
+        for (int i = 0; i < depth; ++i) {
+            next = next.getParent();
+            Preconditions.checkState(next != null);
+        }
+
+        current = next;
+    }
+
+    @Override
+    public final Optional<NormalizedNode<?, ?>> readNode(@Nonnull final PathArgument child) {
+        throw new UnsupportedOperationException("Not implemented");
+    }
+
+    @Override
+    public void close() {
+        // No-op
+    }
+}