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

[controller.git] / opendaylight / md-sal / sal-dom-spi / src / main / java / org / opendaylight / controller / sal / core / spi / data / DOMStoreReadTransaction.java

diff --git a/opendaylight/md-sal/sal-dom-spi/src/main/java/org/opendaylight/controller/sal/core/spi/data/DOMStoreReadTransaction.java b/opendaylight/md-sal/sal-dom-spi/src/main/java/org/opendaylight/controller/sal/core/spi/data/DOMStoreReadTransaction.java
index 84d09c7cb024a275ebfdfa6edd8a75af00abc3af..306891189a6d7f0f5b0745c9de0e63362fff768c 100644 (file)
--- a/opendaylight/md-sal/sal-dom-spi/src/main/java/org/opendaylight/controller/sal/core/spi/data/DOMStoreReadTransaction.java
+++ b/opendaylight/md-sal/sal-dom-spi/src/main/java/org/opendaylight/controller/sal/core/spi/data/DOMStoreReadTransaction.java
@@ -34,4 +34,26 @@ public interface DOMStoreReadTransaction extends DOMStoreTransaction {
      *         </ul>
      */
     CheckedFuture<Optional<NormalizedNode<?,?>>, ReadFailedException> read(YangInstanceIdentifier path);
+
+    /**
+     * Checks if data is available in the logical data store located at provided path.
+     * <p>
+     *
+     * Note: a successful result from this method makes no guarantee that a subsequent call to {@link #read}
+     * will succeed. It is possible that the data resides in a data store on a remote node and, if that
+     * node goes down or a network failure occurs, a subsequent read would fail. Another scenario is if
+     * the data is deleted in between the calls to <code>exists</code> and <code>read</code>
+     *
+     * @param path
+     *            Path which uniquely identifies subtree which client want to
+     *            check existence of
+     * @return a CheckFuture containing the result of the check.
+     *         <ul>
+     *         <li>If the data at the supplied path exists, the Future returns a Boolean
+     *         whose value is true, false otherwise</li>
+     *         <li>If checking for the data fails, the Future will fail with a
+     *         {@link ReadFailedException} or an exception derived from ReadFailedException.</li>
+     *         </ul>
+     */
+    CheckedFuture<Boolean, ReadFailedException> exists(YangInstanceIdentifier path);
 }