Allow SnapshotBackedReadTransaction customization

[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 719a6f0499d4423040e5547b82a3bc957c30abbe..ede5bae35b0a1bf26d39759edb0f6379c089a13a 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
@@ -7,17 +7,16 @@
  */
 package org.opendaylight.controller.sal.core.spi.data;
 
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.CheckedFuture;
 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 
-import com.google.common.base.Optional;
-import com.google.common.util.concurrent.CheckedFuture;
-
 public interface DOMStoreReadTransaction extends DOMStoreTransaction {
 
     /**
-     * Reads data from provided logical data store located at provided path
+     * Reads data from provided logical data store located at provided path.
      *
      * @param path
      *            Path which uniquely identifies subtree which client want to
@@ -36,7 +35,13 @@ public interface DOMStoreReadTransaction extends DOMStoreTransaction {
     CheckedFuture<Optional<NormalizedNode<?,?>>, ReadFailedException> read(YangInstanceIdentifier path);
 
     /**
-     * Checks if data is available in the logical data store located at provided 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