X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-common-api%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fmd%2Fsal%2Fcommon%2Fapi%2Fdata%2FAsyncDataChangeListener.java;h=0bdaf7bf3766736aa76337a1e6e772e036ed0cb5;hp=49f07bc52b4f8aecefab507121d8d91984f1f8d3;hb=dfa2da6098a0c423c0a7bf45b7229931cea67f85;hpb=3ca2b85262ea5d9a8f638b03477c968549133232

diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncDataChangeListener.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncDataChangeListener.java
index 49f07bc52b..0bdaf7bf37 100644
--- a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncDataChangeListener.java
+++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncDataChangeListener.java
@@ -11,13 +11,45 @@ import java.util.EventListener;
 
 import org.opendaylight.yangtools.concepts.Path;
 
+/**
+ * Listener of data change events on particular subtree.
+ *
+ * <p>
+ * User-supplied implementations of this listener interface MUST register via
+ * {@link AsyncDataBroker#registerDataChangeListener(LogicalDatastoreType, Path, AsyncDataChangeListener, AsyncDataBroker.DataChangeScope)}
+ * in order to start receiving data change events, which capture state changes
+ * in a subtree.
+ *
+ * <p>
+ * <b>Implementation Note:</b> This interface is intended to be implemented
+ * by users of MD-SAL.
+ *
+ * @param <P>
+ *            Type of path (subtree identifier), which represents location in
+ *            tree
+ * @param <D>
+ *            Type of data (payload), which represents data payload
+ */
 public interface AsyncDataChangeListener<P extends Path<P>, D> extends EventListener {
     /**
-     * Note that this method may be invoked from a shared thread pool, so
-     * implementations SHOULD NOT perform CPU-intensive operations and they
-     * definitely MUST NOT invoke any potentially blocking operations.
      *
-     * @param change Data Change Event being delivered.
+     * Invoked when there is data change for the particular path, which was used to
+     * register this listener.
+     * <p>
+     * This method may be also invoked during registration of the listener if
+     * there is any preexisting data in the conceptual data tree for supplied path.
+     * This initial event will contain all preexisting data as created.
+     *
+     * <p>
+     * <b>Note</b>: This method may be invoked from a shared thread pool.
+     * <li>Implementations <b>SHOULD NOT</b> perform CPU-intensive operations on the calling thread.
+     * <li>Implementations <b>MUST NOT block the calling thread</b> - to do so could lead to deadlock
+     * scenarios.
+     *
+     *<br>
+     *
+     * @param change
+     *            Data Change Event being delivered.
      */
     void onDataChanged(AsyncDataChangeEvent<P, D> change);
 }