BUG-2673: Introduced new more low-level DOM Data Change APIs

[controller.git] / opendaylight / md-sal / sal-dom-api / src / main / java / org / opendaylight / controller / md / sal / dom / api / DOMDataTreeChangeService.java

diff --git a/opendaylight/md-sal/sal-dom-api/src/main/java/org/opendaylight/controller/md/sal/dom/api/DOMDataTreeChangeService.java b/opendaylight/md-sal/sal-dom-api/src/main/java/org/opendaylight/controller/md/sal/dom/api/DOMDataTreeChangeService.java
new file mode 100644 (file)
index 0000000..e001dbb
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+++ b/opendaylight/md-sal/sal-dom-api/src/main/java/org/opendaylight/controller/md/sal/dom/api/DOMDataTreeChangeService.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2015 Cisco 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.md.sal.dom.api;
+
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.concepts.ListenerRegistration;
+
+/**
+ * A {@link DOMService} which allows users to register for changes to a
+ * subtree.
+ */
+public interface DOMDataTreeChangeService extends DOMService {
+    /**
+     * Registers a {@link DOMDataTreeChangeListener} to receive
+     * notifications when data changes under a given path in the conceptual data
+     * tree.
+     * <p>
+     * You are able to register for notifications  for any node or subtree
+     * which can be represented using {@link DOMDataTreeIdentifier}.
+     * <p>
+     *
+     * You are able to register for data change notifications for a subtree or leaf
+     * even if it does not exist. You will receive notification once that node is
+     * created.
+     * <p>
+     * If there is any pre-existing data in the data tree for the path for which you are
+     * registering, you will receive an initial data change event, which will
+     * contain all pre-existing data, marked as created.
+     *
+     * <p>
+     * This method returns a {@link ListenerRegistration} object. To
+     * "unregister" your listener for changes call the {@link ListenerRegistration#close()}
+     * method on the returned object.
+     * <p>
+     * You MUST explicitly unregister your listener when you no longer want to receive
+     * notifications. This is especially true in OSGi environments, where failure to
+     * do so during bundle shutdown can lead to stale listeners being still registered.
+     *
+     * @param treeId
+     *            Data tree identifier of the subtree which should be watched for
+     *            changes.
+     * @param listener
+     *            Listener instance which is being registered
+     * @return Listener registration object, which may be used to unregister
+     *         your listener using {@link ListenerRegistration#close()} to stop
+     *         delivery of change events.
+     */
+    @Nonnull <L extends DOMDataTreeChangeListener> ListenerRegistration<L> registerDataTreeChangeListener(@Nonnull DOMDataTreeIdentifier treeId, @Nonnull L listener);
+}